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如何在Android中利用imageview实现一个图片缩放功能？相信很多没有经验的人对此束手无策，为此本文总结了问题出现的原因和解决方法，通过这篇文章希望你能解决这个问题。
Android 自定义imageview实现图片缩放实例详解
觉得这个自定义的imageview很好用 性能不错 所以拿出来分享给大家 因为不会做gif图 所以项目效果 就不好贴出来了 把代码贴出来
1.项目结构图
2.Compat.class
package com.suo.image;
import android.os.Build.VERSION;
import android.os.Build.VERSION_CODES;
import android.view.View;
public class Compat {
private static final int SIXTY_FPS_INTERVAL = 1000 / 60;
public static void postOnAnimation(View view, Runnable runnable) {
if (VERSION.SDK_INT >= VERSION_CODES.JELLY_BEAN) {
SDK16.postOnAnimation(view, runnable);
} else {
view.postDelayed(runnable, SIXTY_FPS_INTERVAL);
}
}
}
3.HackyViewPager.class
package com.suo.image;
import android.content.Context;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.view.MotionEvent;
/**
* Hacky fix for Issue #4 and
* http://code.google.com/p/android/issues/detail?id=18990
*
* ScaleGestureDetector seems to mess up the touch events, which means that
* ViewGroups which make use of onInterceptTouchEvent throw a lot of
* IllegalArgumentException: pointerIndex out of range.
*
* There's not much I can do in my code for now, but we can mask the result by
* just catching the problem and ignoring it.
*
* @author Chris Banes
*/
public class HackyViewPager extends ViewPager {
public HackyViewPager(Context context) {
super(context);
}
public HackyViewPager(Context context, AttributeSet attrs) {
super(context, attrs);
// TODO Auto-generated constructor stub
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
try {
return super.onInterceptTouchEvent(ev);
} catch (IllegalArgumentException e) {
e.printStackTrace();
return false;
}
}
}
4.IScaleView.class
/*******************************************************************************
* Copyright 2011, 2012 Chris Banes.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*******************************************************************************/
package com.suo.image;
import android.graphics.RectF;
import android.view.View;
import android.widget.ImageView;
public interface IScaleView {
/**
* Returns true if the ScaleView is set to allow zooming of Scales.
*
* @return true if the ScaleView allows zooming.
*/
boolean canZoom();
/**
* Gets the Display Rectangle of the currently displayed Drawable. The
* Rectangle is relative to this View and includes all scaling and
* translations.
*
* @return - RectF of Displayed Drawable
*/
RectF getDisplayRect();
/**
* @return The current minimum scale level. What this value represents depends on the current {@link android.widget.ImageView.ScaleType}.
*/
float getMinScale();
/**
* @return The current middle scale level. What this value represents depends on the current {@link android.widget.ImageView.ScaleType}.
*/
float getMidScale();
/**
* @return The current maximum scale level. What this value represents depends on the current {@link android.widget.ImageView.ScaleType}.
*/
float getMaxScale();
/**
* Returns the current scale value
*
* @return float - current scale value
*/
float getScale();
/**
* Return the current scale type in use by the ImageView.
*/
ImageView.ScaleType getScaleType();
/**
* Whether to allow the ImageView's parent to intercept the touch event when the Scale is scroll to it's horizontal edge.
*/
void setAllowParentInterceptOnEdge(boolean allow);
/**
* Sets the minimum scale level. What this value represents depends on the current {@link android.widget.ImageView.ScaleType}.
*/
void setMinScale(float minScale);
/**
* Sets the middle scale level. What this value represents depends on the current {@link android.widget.ImageView.ScaleType}.
*/
void setMidScale(float midScale);
/**
* Sets the maximum scale level. What this value represents depends on the current {@link android.widget.ImageView.ScaleType}.
*/
void setMaxScale(float maxScale);
/**
* Register a callback to be invoked when the Scale displayed by this view is long-pressed.
*
* @param listener - Listener to be registered.
*/
void setOnLongClickListener(View.OnLongClickListener listener);
/**
* Register a callback to be invoked when the Matrix has changed for this
* View. An example would be the user panning or scaling the Scale.
*
* @param listener - Listener to be registered.
*/
void setOnMatrixChangeListener(ScaleViewAttacher.OnMatrixChangedListener listener);
/**
* Register a callback to be invoked when the Scale displayed by this View
* is tapped with a single tap.
*
* @param listener - Listener to be registered.
*/
void setOnScaleTapListener(ScaleViewAttacher.OnScaleTapListener listener);
/**
* Register a callback to be invoked when the View is tapped with a single
* tap.
*
* @param listener - Listener to be registered.
*/
void setOnViewTapListener(ScaleViewAttacher.OnViewTapListener listener);
/**
* Controls how the image should be resized or moved to match the size of
* the ImageView. Any scaling or panning will happen within the confines of
* this {@link android.widget.ImageView.ScaleType}.
*
* @param scaleType - The desired scaling mode.
*/
void setScaleType(ImageView.ScaleType scaleType);
/**
* Allows you to enable/disable the zoom functionality on the ImageView.
* When disable the ImageView reverts to using the FIT_CENTER matrix.
*
* @param zoomable - Whether the zoom functionality is enabled.
*/
void setZoomable(boolean zoomable);
/**
* Zooms to the specified scale, around the focal point given.
*
* @param scale - Scale to zoom to
* @param focalX - X Focus Point
* @param focalY - Y Focus Point
*/
void zoomTo(float scale, float focalX, float focalY);
}
5.ScaleView
/*******************************************************************************
* Copyright 2011, 2012 Chris Banes.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*******************************************************************************/
package com.suo.image;
import com.suo.image.ScaleViewAttacher.OnMatrixChangedListener;
import com.suo.image.ScaleViewAttacher.OnScaleTapListener;
import com.suo.image.ScaleViewAttacher.OnViewTapListener;
import android.content.Context;
import android.graphics.RectF;
import android.graphics.drawable.Drawable;
import android.net.Uri;
import android.util.AttributeSet;
import android.widget.ImageView;
public class ScaleView extends ImageView implements IScaleView {
@SuppressWarnings("unused")
private static final String TAG = "ScaleView";
private final ScaleViewAttacher mAttacher;
private ScaleType mPendingScaleType;
public ScaleView(Context context) {
this(context, null);
setZoomable(false);
}
public ScaleView(Context context, AttributeSet attr) {
this(context, attr, 0);
}
public ScaleView(Context context, AttributeSet attr, int defStyle) {
super(context, attr, defStyle);
super.setScaleType(ScaleType.MATRIX);
mAttacher = new ScaleViewAttacher(this);
if (null != mPendingScaleType) {
setScaleType(mPendingScaleType);
mPendingScaleType = null;
}
}
public void setOnClickListener(OnClickListener listener){
mAttacher.setOnClickLinstener(listener);
}
@Override
public boolean canZoom() {
return mAttacher.canZoom();
}
@Override
public RectF getDisplayRect() {
return mAttacher.getDisplayRect();
}
@Override
public float getMinScale() {
return mAttacher.getMinScale();
}
@Override
public float getMidScale() {
return mAttacher.getMidScale();
}
@Override
public float getMaxScale() {
return mAttacher.getMaxScale();
}
@Override
public float getScale() {
return mAttacher.getScale();
}
@Override
public ScaleType getScaleType() {
return mAttacher.getScaleType();
}
@Override
public void setAllowParentInterceptOnEdge(boolean allow) {
mAttacher.setAllowParentInterceptOnEdge(allow);
}
@Override
public void setMinScale(float minScale) {
mAttacher.setMinScale(minScale);
}
@Override
public void setMidScale(float midScale) {
mAttacher.setMidScale(midScale);
}
@Override
public void setMaxScale(float maxScale) {
mAttacher.setMaxScale(maxScale);
}
@Override
// setImageBitmap calls through to this method
public void setImageDrawable(Drawable drawable) {
super.setImageDrawable(drawable);
if (null != mAttacher) {
mAttacher.update();
}
}
@Override
public void setImageResource(int resId) {
super.setImageResource(resId);
if (null != mAttacher) {
mAttacher.update();
}
}
@Override
public void setImageURI(Uri uri) {
super.setImageURI(uri);
if (null != mAttacher) {
mAttacher.update();
}
}
@Override
public void setOnMatrixChangeListener(OnMatrixChangedListener listener) {
mAttacher.setOnMatrixChangeListener(listener);
}
@Override
public void setOnLongClickListener(OnLongClickListener l) {
mAttacher.setOnLongClickListener(l);
}
@Override
public void setOnScaleTapListener(OnScaleTapListener listener) {
mAttacher.setOnScaleTapListener(listener);
}
@Override
public void setOnViewTapListener(OnViewTapListener listener) {
mAttacher.setOnViewTapListener(listener);
}
@Override
public void setScaleType(ScaleType scaleType) {
if (null != mAttacher) {
mAttacher.setScaleType(scaleType);
} else {
mPendingScaleType = scaleType;
}
}
@Override
public void setZoomable(boolean zoomable) {
mAttacher.setZoomable(zoomable);
}
@Override
public void zoomTo(float scale, float focalX, float focalY) {
mAttacher.zoomTo(scale, focalX, focalY);
}
@Override
protected void onDetachedFromWindow() {
mAttacher.cleanup();
super.onDetachedFromWindow();
}
}
6.ScaleViewAttacher 这个是最关键的
/*******************************************************************************
* Copyright 2011, 2012 Chris Banes.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*******************************************************************************/
package com.suo.image;
import android.content.Context;
import android.graphics.Matrix;
import android.graphics.Matrix.ScaleToFit;
import android.graphics.RectF;
import android.graphics.drawable.Drawable;
import android.util.Log;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnLongClickListener;
import android.view.ViewTreeObserver;
import android.widget.ImageView;
import android.widget.ImageView.ScaleType;
import java.lang.ref.WeakReference;
public class ScaleViewAttacher implements IScaleView, View.OnTouchListener, VersionedGestureDetector.OnGestureListener,
GestureDetector.OnDoubleTapListener, ViewTreeObserver.OnGlobalLayoutListener {
static final String LOG_TAG = "ScaleViewAttacher";
// let debug flag be dynamic, but still Proguard can be used to remove from release builds
static final boolean DEBUG = Log.isLoggable(LOG_TAG, Log.DEBUG);
static final int EDGE_NONE = -1;
static final int EDGE_LEFT = 0;
static final int EDGE_RIGHT = 1;
static final int EDGE_BOTH = 2;
public static final float DEFAULT_MAX_SCALE = 3.0f;
public static final float DEFAULT_MID_SCALE = 1.75f;
public static final float DEFAULT_MIN_SCALE = 1.0f;
private float mMinScale = DEFAULT_MIN_SCALE;
private float mMidScale = DEFAULT_MID_SCALE;
private float mMaxScale = DEFAULT_MAX_SCALE;
private boolean mAllowParentInterceptOnEdge = true;
private static void checkZoomLevels(float minZoom, float midZoom, float maxZoom) {
if (minZoom >= midZoom) {
throw new IllegalArgumentException("MinZoom should be less than MidZoom");
} else if (midZoom >= maxZoom) {
throw new IllegalArgumentException("MidZoom should be less than MaxZoom");
}
}
/**
* @return true if the ImageView exists, and it's Drawable existss
*/
private static boolean hasDrawable(ImageView imageView) {
return null != imageView && null != imageView.getDrawable();
}
/**
* @return true if the ScaleType is supported.
*/
private static boolean isSupportedScaleType(final ScaleType scaleType) {
if (null == scaleType) {
return false;
}
switch (scaleType) {
case MATRIX:
throw new IllegalArgumentException(scaleType.name() + " is not supported in ScaleView");
default:
return true;
}
}
/**
* Set's the ImageView's ScaleType to Matrix.
*/
private static void setImageViewScaleTypeMatrix(ImageView imageView) {
if (null != imageView) {
if (imageView instanceof ScaleView) {
/**
* ScaleView sets it's own ScaleType to Matrix, then diverts all
* calls setScaleType to this.setScaleType. Basically we don't
* need to do anything here
*/
} else {
imageView.setScaleType(ScaleType.MATRIX);
}
}
}
private WeakReference<ImageView> mImageView;
private ViewTreeObserver mViewTreeObserver;
// Gesture Detectors
private GestureDetector mGestureDetector;
private VersionedGestureDetector mScaleDragDetector;
// These are set so we don't keep allocating them on the heap
private final Matrix mBaseMatrix = new Matrix();
private final Matrix mDrawMatrix = new Matrix();
private final Matrix mSuppMatrix = new Matrix();
private final RectF mDisplayRect = new RectF();
private final float[] mMatrixValues = new float[9];
// Listeners
private OnMatrixChangedListener mMatrixChangeListener;
private OnScaleTapListener mScaleTapListener;
private OnViewTapListener mViewTapListener;
private OnLongClickListener mLongClickListener;
private int mIvTop, mIvRight, mIvBottom, mIvLeft;
private FlingRunnable mCurrentFlingRunnable;
private int mScrollEdge = EDGE_BOTH;
private boolean mZoomEnabled;
private ScaleType mScaleType = ScaleType.FIT_CENTER;
private OnClickListener onClickListener;
public ScaleViewAttacher(ImageView imageView) {
mImageView = new WeakReference<ImageView>(imageView);
imageView.setOnTouchListener(this);
mViewTreeObserver = imageView.getViewTreeObserver();
if (mViewTreeObserver != null) {
mViewTreeObserver.addOnGlobalLayoutListener(this);
}
onClickListener = null;
// Make sure we using MATRIX Scale Type
setImageViewScaleTypeMatrix(imageView);
if (!imageView.isInEditMode()) {
// Create Gesture Detectors...
mScaleDragDetector = VersionedGestureDetector.newInstance(imageView.getContext(), this);
mGestureDetector = new GestureDetector(imageView.getContext(),
new GestureDetector.SimpleOnGestureListener() {
// forward long click listener
@Override
public void onLongPress(MotionEvent e) {
if(null != mLongClickListener) {
mLongClickListener.onLongClick(mImageView.get());
}
}});
mGestureDetector.setOnDoubleTapListener(this);
// Finally, update the UI so that we're zoomable
setZoomable(true);
}
}
@Override
public final boolean canZoom() {
return mZoomEnabled;
}
/**
* Clean-up the resources attached to this object. This needs to be called
* when the ImageView is no longer used. A good example is from
* {@link android.view.View#onDetachedFromWindow()} or from {@link android.app.Activity#onDestroy()}.
* This is automatically called if you are using {@link ScaleView.co.senab.Scaleview.ScaleView}.
*/
@SuppressWarnings("deprecation")
public final void cleanup() {
if (null != mImageView) {
android.view.ViewTreeObserver obs = mImageView.get().getViewTreeObserver();
if (obs != null) {
obs.removeGlobalOnLayoutListener(this);
}
}
mViewTreeObserver = null;
// Clear listeners too
mMatrixChangeListener = null;
mScaleTapListener = null;
mViewTapListener = null;
// Finally, clear ImageView
mImageView = null;
}
@Override
public final RectF getDisplayRect() {
checkMatrixBounds();
return getDisplayRect(getDisplayMatrix());
}
public final ImageView getImageView() {
ImageView imageView = null;
if (null != mImageView) {
imageView = mImageView.get();
}
// If we don't have an ImageView, call cleanup()
if (null == imageView) {
cleanup();
// throw new IllegalStateException(
// "ImageView no longer exists. You should not use this ScaleViewAttacher any more.");
}
return imageView;
}
@Override
public float getMinScale() {
return mMinScale;
}
@Override
public float getMidScale() {
return mMidScale;
}
@Override
public float getMaxScale() {
return mMaxScale;
}
@Override
public final float getScale() {
return getValue(mSuppMatrix, Matrix.MSCALE_X);
}
@Override
public final ScaleType getScaleType() {
return mScaleType;
}
public final boolean onDoubleTap(MotionEvent ev) {
try {
float scale = getScale();
float x = ev.getX();
float y = ev.getY();
if (scale < mMidScale) {
zoomTo(mMidScale, x, y);
} else if (scale >= mMidScale && scale < mMaxScale) {
zoomTo(mMaxScale, x, y);
} else {
zoomTo(mMinScale, x, y);
}
} catch (ArrayIndexOutOfBoundsException e) {
// Can sometimes happen when getX() and getY() is called
}
return true;
}
public final boolean onDoubleTapEvent(MotionEvent e) {
// Wait for the confirmed onDoubleTap() instead
return false;
}
public final void onDrag(float dx, float dy) {
if (DEBUG) {
Log.d(LOG_TAG, String.format("onDrag: dx: %.2f. dy: %.2f", dx, dy));
}
ImageView imageView = getImageView();
if (null != imageView && hasDrawable(imageView)) {
mSuppMatrix.postTranslate(dx, dy);
checkAndDisplayMatrix();
/**
* Here we decide whether to let the ImageView's parent to start
* taking over the touch event.
*
* First we check whether this function is enabled. We never want the
* parent to take over if we're scaling. We then check the edge we're
* on, and the direction of the scroll (i.e. if we're pulling against
* the edge, aka 'overscrolling', let the parent take over).
*/
if (mAllowParentInterceptOnEdge && !mScaleDragDetector.isScaling()) {
if (mScrollEdge == EDGE_BOTH || (mScrollEdge == EDGE_LEFT && dx >= 1f)
|| (mScrollEdge == EDGE_RIGHT && dx <= -1f)) {
android.view.ViewParent vParent = imageView.getParent();
if (vParent != null) {
vParent.requestDisallowInterceptTouchEvent(false);
}
}
}
}
}
@Override
public final void onFling(float startX, float startY, float velocityX, float velocityY) {
if (DEBUG) {
Log.d(LOG_TAG, "onFling. sX: " + startX + " sY: " + startY + " Vx: " + velocityX + " Vy: " + velocityY);
}
ImageView imageView = getImageView();
if (hasDrawable(imageView)) {
mCurrentFlingRunnable = new FlingRunnable(imageView.getContext());
mCurrentFlingRunnable.fling(imageView.getWidth(), imageView.getHeight(), (int) velocityX, (int) velocityY);
imageView.post(mCurrentFlingRunnable);
}
}
@Override
public final void onGlobalLayout() {
ImageView imageView = getImageView();
if (null != imageView && mZoomEnabled) {
final int top = imageView.getTop();
final int right = imageView.getRight();
final int bottom = imageView.getBottom();
final int left = imageView.getLeft();
/**
* We need to check whether the ImageView's bounds have changed.
* This would be easier if we targeted API 11+ as we could just use
* View.OnLayoutChangeListener. Instead we have to replicate the
* work, keeping track of the ImageView's bounds and then checking
* if the values change.
*/
if (top != mIvTop || bottom != mIvBottom || left != mIvLeft || right != mIvRight) {
// Update our base matrix, as the bounds have changed
updateBaseMatrix(imageView.getDrawable());
// Update values as something has changed
mIvTop = top;
mIvRight = right;
mIvBottom = bottom;
mIvLeft = left;
}
}
}
public final void setOnClickLinstener(OnClickListener listener){
onClickListener = listener;
}
public final void onScale(float scaleFactor, float focusX, float focusY) {
if (DEBUG) {
Log.d(LOG_TAG, String.format("onScale: scale: %.2f. fX: %.2f. fY: %.2f", scaleFactor, focusX, focusY));
}
if (hasDrawable(getImageView()) && (getScale() < mMaxScale || scaleFactor < 1f)) {
mSuppMatrix.postScale(scaleFactor, scaleFactor, focusX, focusY);
checkAndDisplayMatrix();
}
}
public final boolean onSingleTapConfirmed(MotionEvent e) {
ImageView imageView = getImageView();
if (null != imageView) {
if (null != mScaleTapListener) {
final RectF displayRect = getDisplayRect();
if (null != displayRect) {
final float x = e.getX(), y = e.getY();
// Check to see if the user tapped on the Scale
if (displayRect.contains(x, y)) {
float xResult = (x - displayRect.left) / displayRect.width();
float yResult = (y - displayRect.top) / displayRect.height();
mScaleTapListener.onScaleTap(imageView, xResult, yResult);
return true;
}
}
}
if (null != mViewTapListener) {
mViewTapListener.onViewTap(imageView, e.getX(), e.getY());
}
}
return false;
}
private float lastPosX, lastPosY;
private long firClick = 0;
@Override
public final boolean onTouch(View v, MotionEvent ev) {
boolean handled = false;
if (mZoomEnabled) {
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
// First, disable the Parent from intercepting the touch
// event
android.view.ViewParent vParent = v.getParent();
if (vParent != null) {
vParent.requestDisallowInterceptTouchEvent(true);
}
lastPosX = ev.getX();
lastPosY = ev.getY();
// If we're flinging, and the user presses down, cancel
// fling
cancelFling();
break;
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP:
// If the user has zoomed less than min scale, zoom back
// to min scale
if (getScale() < mMinScale) {
RectF rect = getDisplayRect();
if (null != rect) {
v.post(new AnimatedZoomRunnable(getScale(), mMinScale, rect.centerX(), rect.centerY()));
handled = true;
}
}
if(ev.getX() == lastPosX && ev.getY() == lastPosY){
long time = System.currentTimeMillis();
if(time - firClick > 500){
firClick = System.currentTimeMillis();
if(onClickListener != null){
onClickListener.onClick(getImageView());
}
}
}
break;
}
// Check to see if the user double tapped
if (null != mGestureDetector && mGestureDetector.onTouchEvent(ev)) {
handled = true;
}
// Finally, try the Scale/Drag detector
if (null != mScaleDragDetector && mScaleDragDetector.onTouchEvent(ev)) {
handled = true;
}
}
return handled;
}
@Override
public void setAllowParentInterceptOnEdge(boolean allow) {
mAllowParentInterceptOnEdge = allow;
}
@Override
public void setMinScale(float minScale) {
checkZoomLevels(minScale, mMidScale, mMaxScale);
mMinScale = minScale;
}
@Override
public void setMidScale(float midScale) {
checkZoomLevels(mMinScale, midScale, mMaxScale);
mMidScale = midScale;
}
@Override
public void setMaxScale(float maxScale) {
checkZoomLevels(mMinScale, mMidScale, maxScale);
mMaxScale = maxScale;
}
@Override
public final void setOnLongClickListener(OnLongClickListener listener) {
mLongClickListener = listener;
}
@Override
public final void setOnMatrixChangeListener(OnMatrixChangedListener listener) {
mMatrixChangeListener = listener;
}
@Override
public final void setOnScaleTapListener(OnScaleTapListener listener) {
mScaleTapListener = listener;
}
@Override
public final void setOnViewTapListener(OnViewTapListener listener) {
mViewTapListener = listener;
}
@Override
public final void setScaleType(ScaleType scaleType) {
if (isSupportedScaleType(scaleType) && scaleType != mScaleType) {
// mScaleType = scaleType;
// Finally update
update();
}
}
@Override
public final void setZoomable(boolean zoomable) {
mZoomEnabled = zoomable;
update();
}
public final void update() {
ImageView imageView = getImageView();
if (null != imageView) {
if (mZoomEnabled) {
// Make sure we using MATRIX Scale Type
setImageViewScaleTypeMatrix(imageView);
// Update the base matrix using the current drawable
updateBaseMatrix(imageView.getDrawable());
} else {
// Reset the Matrix...
resetMatrix();
}
}
}
@Override
public final void zoomTo(float scale, float focalX, float focalY) {
ImageView imageView = getImageView();
if (null != imageView) {
imageView.post(new AnimatedZoomRunnable(getScale(), scale, focalX, focalY));
}
}
protected Matrix getDisplayMatrix() {
mDrawMatrix.set(mBaseMatrix);
mDrawMatrix.postConcat(mSuppMatrix);
return mDrawMatrix;
}
private void cancelFling() {
if (null != mCurrentFlingRunnable) {
mCurrentFlingRunnable.cancelFling();
mCurrentFlingRunnable = null;
}
}
/**
* Helper method that simply checks the Matrix, and then displays the result
*/
private void checkAndDisplayMatrix() {
checkMatrixBounds();
setImageViewMatrix(getDisplayMatrix());
}
private void checkImageViewScaleType() {
ImageView imageView = getImageView();
/**
* ScaleView's getScaleType() will just divert to this.getScaleType() so
* only call if we're not attached to a ScaleView.
*/
if (null != imageView && !(imageView instanceof ScaleView)) {
if (imageView.getScaleType() != ScaleType.MATRIX) {
throw new IllegalStateException(
"The ImageView's ScaleType has been changed since attaching a ScaleViewAttacher");
}
}
}
private void checkMatrixBounds() {
final ImageView imageView = getImageView();
if (null == imageView) {
return;
}
final RectF rect = getDisplayRect(getDisplayMatrix());
if (null == rect) {
return;
}
final float height = rect.height(), width = rect.width();
float deltaX = 0, deltaY = 0;
final int viewHeight = imageView.getHeight();
if (height <= viewHeight) {
switch (mScaleType) {
case FIT_START:
deltaY = -rect.top;
break;
case FIT_END:
deltaY = viewHeight - height - rect.top;
break;
default:
deltaY = (viewHeight - height) / 2 - rect.top;
break;
}
} else if (rect.top > 0) {
deltaY = -rect.top;
} else if (rect.bottom < viewHeight) {
deltaY = viewHeight - rect.bottom;
}
final int viewWidth = imageView.getWidth();
if (width <= viewWidth) {
switch (mScaleType) {
case FIT_START:
deltaX = -rect.left;
break;
case FIT_END:
deltaX = viewWidth - width - rect.left;
break;
default:
deltaX = (viewWidth - width) / 2 - rect.left;
break;
}
mScrollEdge = EDGE_BOTH;
} else if (rect.left > 0) {
mScrollEdge = EDGE_LEFT;
deltaX = -rect.left;
} else if (rect.right < viewWidth) {
deltaX = viewWidth - rect.right;
mScrollEdge = EDGE_RIGHT;
} else {
mScrollEdge = EDGE_NONE;
}
// Finally actually translate the matrix
mSuppMatrix.postTranslate(deltaX, deltaY);
}
/**
* Helper method that maps the supplied Matrix to the current Drawable
*
* @param matrix - Matrix to map Drawable against
* @return RectF - Displayed Rectangle
*/
private RectF getDisplayRect(Matrix matrix) {
ImageView imageView = getImageView();
if (null != imageView) {
Drawable d = imageView.getDrawable();
if (null != d) {
mDisplayRect.set(0, 0, d.getIntrinsicWidth(), d.getIntrinsicHeight());
matrix.mapRect(mDisplayRect);
return mDisplayRect;
}
}
return null;
}
/**
* Helper method that 'unpacks' a Matrix and returns the required value
*
* @param matrix - Matrix to unpack
* @param whichValue - Which value from Matrix.M* to return
* @return float - returned value
*/
private float getValue(Matrix matrix, int whichValue) {
matrix.getValues(mMatrixValues);
return mMatrixValues[whichValue];
}
/**
* Resets the Matrix back to FIT_CENTER, and then displays it.s
*/
private void resetMatrix() {
mSuppMatrix.reset();
setImageViewMatrix(getDisplayMatrix());
checkMatrixBounds();
}
private void setImageViewMatrix(Matrix matrix) {
ImageView imageView = getImageView();
if (null != imageView) {
checkImageViewScaleType();
imageView.setImageMatrix(matrix);
// Call MatrixChangedListener if needed
if (null != mMatrixChangeListener) {
RectF displayRect = getDisplayRect(matrix);
if (null != displayRect) {
mMatrixChangeListener.onMatrixChanged(displayRect);
}
}
}
}
/**
* Calculate Matrix for FIT_CENTER
*
* @param d - Drawable being displayed
*/
private void updateBaseMatrix(Drawable d) {
ImageView imageView = getImageView();
if (null == imageView || null == d) {
return;
}
final float viewWidth = imageView.getWidth();
final float viewHeight = imageView.getHeight();
final int drawableWidth = d.getIntrinsicWidth();
final int drawableHeight = d.getIntrinsicHeight();
mBaseMatrix.reset();
final float widthScale = viewWidth / drawableWidth;
final float heightScale = viewHeight / drawableHeight;
if (mScaleType == ScaleType.CENTER) {
mBaseMatrix.postTranslate((viewWidth - drawableWidth) / 2F, (viewHeight - drawableHeight) / 2F);
} else if (mScaleType == ScaleType.CENTER_CROP) {
float scale = Math.max(widthScale, heightScale);
mBaseMatrix.postScale(scale, scale);
mBaseMatrix.postTranslate((viewWidth - drawableWidth * scale) / 2F,
(viewHeight - drawableHeight * scale) / 2F);
} else if (mScaleType == ScaleType.CENTER_INSIDE) {
float scale = Math.min(1.0f, Math.min(widthScale, heightScale));
mBaseMatrix.postScale(scale, scale);
mBaseMatrix.postTranslate((viewWidth - drawableWidth * scale) / 2F,
(viewHeight - drawableHeight * scale) / 2F);
} else {
RectF mTempSrc = new RectF(0, 0, drawableWidth, drawableHeight);
RectF mTempDst = new RectF(0, 0, viewWidth, viewHeight);
switch (mScaleType) {
case FIT_CENTER:
mBaseMatrix.setRectToRect(mTempSrc, mTempDst, ScaleToFit.CENTER);
break;
case FIT_START:
mBaseMatrix.setRectToRect(mTempSrc, mTempDst, ScaleToFit.START);
break;
case FIT_END:
mBaseMatrix.setRectToRect(mTempSrc, mTempDst, ScaleToFit.END);
break;
case FIT_XY:
mBaseMatrix.setRectToRect(mTempSrc, mTempDst, ScaleToFit.FILL);
break;
default:
break;
}
}
resetMatrix();
}
/**
* Interface definition for a callback to be invoked when the internal
* Matrix has changed for this View.
*
* @author Chris Banes
*/
public static interface OnMatrixChangedListener {
/**
* Callback for when the Matrix displaying the Drawable has changed.
* This could be because the View's bounds have changed, or the user has
* zoomed.
*
* @param rect - Rectangle displaying the Drawable's new bounds.
*/
void onMatrixChanged(RectF rect);
}
/**
* Interface definition for a callback to be invoked when the Scale is
* tapped with a single tap.
*
* @author Chris Banes
*/
public static interface OnScaleTapListener {
/**
* A callback to receive where the user taps on a Scale. You will only
* receive a callback if the user taps on the actual Scale, tapping on
* 'whitespace' will be ignored.
*
* @param view - View the user tapped.
* @param x - where the user tapped from the of the Drawable, as
* percentage of the Drawable width.
* @param y - where the user tapped from the top of the Drawable, as
* percentage of the Drawable height.
*/
void onScaleTap(View view, float x, float y);
}
/**
* Interface definition for a callback to be invoked when the ImageView is
* tapped with a single tap.
*
* @author Chris Banes
*/
public static interface OnViewTapListener {
/**
* A callback to receive where the user taps on a ImageView. You will
* receive a callback if the user taps anywhere on the view, tapping on
* 'whitespace' will not be ignored.
*
* @param view - View the user tapped.
* @param x - where the user tapped from the left of the View.
* @param y - where the user tapped from the top of the View.
*/
void onViewTap(View view, float x, float y);
}
private class AnimatedZoomRunnable implements Runnable {
// These are 'postScale' values, means they're compounded each iteration
static final float ANIMATION_SCALE_PER_ITERATION_IN = 1.07f;
static final float ANIMATION_SCALE_PER_ITERATION_OUT = 0.93f;
private final float mFocalX, mFocalY;
private final float mTargetZoom;
private final float mDeltaScale;
public AnimatedZoomRunnable(final float currentZoom, final float targetZoom, final float focalX,
final float focalY) {
mTargetZoom = targetZoom;
mFocalX = focalX;
mFocalY = focalY;
if (currentZoom < targetZoom) {
mDeltaScale = ANIMATION_SCALE_PER_ITERATION_IN;
} else {
mDeltaScale = ANIMATION_SCALE_PER_ITERATION_OUT;
}
}
public void run() {
ImageView imageView = getImageView();
if (null != imageView) {
mSuppMatrix.postScale(mDeltaScale, mDeltaScale, mFocalX, mFocalY);
checkAndDisplayMatrix();
final float currentScale = getScale();
if ((mDeltaScale > 1f && currentScale < mTargetZoom)
|| (mDeltaScale < 1f && mTargetZoom < currentScale)) {
// We haven't hit our target scale yet, so post ourselves
// again
Compat.postOnAnimation(imageView, this);
} else {
// We've scaled past our target zoom, so calculate the
// necessary scale so we're back at target zoom
final float delta = mTargetZoom / currentScale;
mSuppMatrix.postScale(delta, delta, mFocalX, mFocalY);
checkAndDisplayMatrix();
}
}
}
}
private class FlingRunnable implements Runnable {
private final ScrollerProxy mScroller;
private int mCurrentX, mCurrentY;
public FlingRunnable(Context context) {
mScroller = ScrollerProxy.getScroller(context);
}
public void cancelFling() {
if (DEBUG) {
Log.d(LOG_TAG, "Cancel Fling");
}
mScroller.forceFinished(true);
}
public void fling(int viewWidth, int viewHeight, int velocityX, int velocityY) {
final RectF rect = getDisplayRect();
if (null == rect) {
return;
}
final int startX = Math.round(-rect.left);
final int minX, maxX, minY, maxY;
if (viewWidth < rect.width()) {
minX = 0;
maxX = Math.round(rect.width() - viewWidth);
} else {
minX = maxX = startX;
}
final int startY = Math.round(-rect.top);
if (viewHeight < rect.height()) {
minY = 0;
maxY = Math.round(rect.height() - viewHeight);
} else {
minY = maxY = startY;
}
mCurrentX = startX;
mCurrentY = startY;
if (DEBUG) {
Log.d(LOG_TAG, "fling. StartX:" + startX + " StartY:" + startY + " MaxX:" + maxX + " MaxY:" + maxY);
}
// If we actually can move, fling the scroller
if (startX != maxX || startY != maxY) {
mScroller.fling(startX, startY, velocityX, velocityY, minX, maxX, minY, maxY, 0, 0);
}
}
@Override
public void run() {
ImageView imageView = getImageView();
if (null != imageView && mScroller.computeScrollOffset()) {
final int newX = mScroller.getCurrX();
final int newY = mScroller.getCurrY();
if (DEBUG) {
Log.d(LOG_TAG, "fling run(). CurrentX:" + mCurrentX + " CurrentY:" + mCurrentY + " NewX:" + newX
+ " NewY:" + newY);
}
mSuppMatrix.postTranslate(mCurrentX - newX, mCurrentY - newY);
setImageViewMatrix(getDisplayMatrix());
mCurrentX = newX;
mCurrentY = newY;
// Post On animation
Compat.postOnAnimation(imageView, this);
}
}
}
}
7.ScrollerProxy
/*******************************************************************************
* Copyright 2011, 2012 Chris Banes.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*******************************************************************************/
package com.suo.image;
import android.annotation.TargetApi;
import android.content.Context;
import android.os.Build.VERSION;
import android.os.Build.VERSION_CODES;
import android.widget.OverScroller;
import android.widget.Scroller;
public abstract class ScrollerProxy {
public static ScrollerProxy getScroller(Context context) {
if (VERSION.SDK_INT < VERSION_CODES.GINGERBREAD) {
return new PreGingerScroller(context);
} else {
return new GingerScroller(context);
}
}
public abstract boolean computeScrollOffset();
public abstract void fling(int startX, int startY, int velocityX, int velocityY, int minX, int maxX, int minY,
int maxY, int overX, int overY);
public abstract void forceFinished(boolean finished);
public abstract int getCurrX();
public abstract int getCurrY();
@TargetApi(9)
private static class GingerScroller extends ScrollerProxy {
private OverScroller mScroller;
public GingerScroller(Context context) {
mScroller = new OverScroller(context);
}
@Override
public boolean computeScrollOffset() {
return mScroller.computeScrollOffset();
}
@Override
public void fling(int startX, int startY, int velocityX, int velocityY, int minX, int maxX, int minY, int maxY,
int overX, int overY) {
mScroller.fling(startX, startY, velocityX, velocityY, minX, maxX, minY, maxY, overX, overY);
}
@Override
public void forceFinished(boolean finished) {
mScroller.forceFinished(finished);
}
@Override
public int getCurrX() {
return mScroller.getCurrX();
}
@Override
public int getCurrY() {
return mScroller.getCurrY();
}
}
private static class PreGingerScroller extends ScrollerProxy {
private Scroller mScroller;
public PreGingerScroller(Context context) {
mScroller = new Scroller(context);
}
@Override
public boolean computeScrollOffset() {
return mScroller.computeScrollOffset();
}
@Override
public void fling(int startX, int startY, int velocityX, int velocityY, int minX, int maxX, int minY, int maxY,
int overX, int overY) {
mScroller.fling(startX, startY, velocityX, velocityY, minX, maxX, minY, maxY);
}
@Override
public void forceFinished(boolean finished) {
mScroller.forceFinished(finished);
}
@Override
public int getCurrX() {
return mScroller.getCurrX();
}
@Override
public int getCurrY() {
return mScroller.getCurrY();
}
}
}
8.SDK16
/*******************************************************************************
* Copyright 2011, 2012 Chris Banes.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*******************************************************************************/
package com.suo.image;
import android.annotation.TargetApi;
import android.view.View;
@TargetApi(16)
public class SDK16 {
public static void postOnAnimation(View view, Runnable r) {
view.postOnAnimation(r);
}
}
9.VersionedGestureDetector
package com.suo.image;
/*******************************************************************************
* Copyright 2011, 2012 Chris Banes.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*******************************************************************************/
import android.annotation.TargetApi;
import android.content.Context;
import android.os.Build;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.ScaleGestureDetector.OnScaleGestureListener;
import android.view.VelocityTracker;
import android.view.ViewConfiguration;
public abstract class VersionedGestureDetector {
static final String LOG_TAG = "VersionedGestureDetector";
OnGestureListener mListener;
public static VersionedGestureDetector newInstance(Context context, OnGestureListener listener) {
final int sdkVersion = Build.VERSION.SDK_INT;
VersionedGestureDetector detector = null;
if (sdkVersion < Build.VERSION_CODES.ECLAIR) {
detector = new CupcakeDetector(context);
} else if (sdkVersion < Build.VERSION_CODES.FROYO) {
detector = new EclairDetector(context);
} else {
detector = new FroyoDetector(context);
}
detector.mListener = listener;
return detector;
}
public abstract boolean onTouchEvent(MotionEvent ev);
public abstract boolean isScaling();
public static interface OnGestureListener {
public void onDrag(float dx, float dy);
public void onFling(float startX, float startY, float velocityX, float velocityY);
public void onScale(float scaleFactor, float focusX, float focusY);
}
private static class CupcakeDetector extends VersionedGestureDetector {
float mLastTouchX;
float mLastTouchY;
final float mTouchSlop;
final float mMinimumVelocity;
public CupcakeDetector(Context context) {
final ViewConfiguration configuration = ViewConfiguration.get(context);
mMinimumVelocity = configuration.getScaledMinimumFlingVelocity();
mTouchSlop = configuration.getScaledTouchSlop();
}
private VelocityTracker mVelocityTracker;
private boolean mIsDragging;
float getActiveX(MotionEvent ev) {
return ev.getX();
}
float getActiveY(MotionEvent ev) {
return ev.getY();
}
public boolean isScaling() {
return false;
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
boolean result = true;
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN: {
mVelocityTracker = VelocityTracker.obtain();
if (mVelocityTracker != null) {
mVelocityTracker.addMovement(ev);
}
mLastTouchX = getActiveX(ev);
mLastTouchY = getActiveY(ev);
mIsDragging = false;
break;
}
case MotionEvent.ACTION_MOVE: {
final float x = getActiveX(ev);
final float y = getActiveY(ev);
final float dx = x - mLastTouchX, dy = y - mLastTouchY;
if (!mIsDragging) {
// Use Pythagoras to see if drag length is larger than
// touch slop
mIsDragging = Math.sqrt((dx * dx) + (dy * dy)) >= mTouchSlop;
}
if (mIsDragging) {
mListener.onDrag(dx, dy);
mLastTouchX = x;
mLastTouchY = y;
if (null != mVelocityTracker) {
mVelocityTracker.addMovement(ev);
}
}
break;
}
case MotionEvent.ACTION_CANCEL: {
// Recycle Velocity Tracker
if (null != mVelocityTracker) {
mVelocityTracker.recycle();
mVelocityTracker = null;
}
break;
}
case MotionEvent.ACTION_UP: {
if (mIsDragging) {
if (null != mVelocityTracker) {
mLastTouchX = getActiveX(ev);
mLastTouchY = getActiveY(ev);
// Compute velocity within the last 1000ms
mVelocityTracker.addMovement(ev);
mVelocityTracker.computeCurrentVelocity(1000);
final float vX = mVelocityTracker.getXVelocity(), vY = mVelocityTracker.getYVelocity();
// If the velocity is greater than minVelocity, call
// listener
if (Math.max(Math.abs(vX), Math.abs(vY)) >= mMinimumVelocity) {
mListener.onFling(mLastTouchX, mLastTouchY, -vX, -vY);
}
}
}
// Recycle Velocity Tracker
if (null != mVelocityTracker) {
mVelocityTracker.recycle();
mVelocityTracker = null;
}
break;
}
}
return result;
}
}
@TargetApi(5)
private static class EclairDetector extends CupcakeDetector {
private static final int INVALID_POINTER_ID = -1;
private int mActivePointerId = INVALID_POINTER_ID;
private int mActivePointerIndex = 0;
public EclairDetector(Context context) {
super(context);
}
@Override
float getActiveX(MotionEvent ev) {
try {
return ev.getX(mActivePointerIndex);
} catch (Exception e) {
return ev.getX();
}
}
@Override
float getActiveY(MotionEvent ev) {
try {
return ev.getY(mActivePointerIndex);
} catch (Exception e) {
return ev.getY();
}
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
final int action = ev.getAction();
switch (action & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
mActivePointerId = ev.getPointerId(0);
break;
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP:
mActivePointerId = INVALID_POINTER_ID;
break;
case MotionEvent.ACTION_POINTER_UP:
final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
final int pointerId = ev.getPointerId(pointerIndex);
if (pointerId == mActivePointerId) {
// This was our active pointer going up. Choose a new
// active pointer and adjust accordingly.
final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
mActivePointerId = ev.getPointerId(newPointerIndex);
mLastTouchX = ev.getX(newPointerIndex);
mLastTouchY = ev.getY(newPointerIndex);
}
break;
}
mActivePointerIndex = ev.findPointerIndex(mActivePointerId != INVALID_POINTER_ID ? mActivePointerId : 0);
return super.onTouchEvent(ev);
}
}
@TargetApi(8)
private static class FroyoDetector extends EclairDetector {
private final ScaleGestureDetector mDetector;
// Needs to be an inner class so that we don't hit
// VerifyError's on API 4.
private final OnScaleGestureListener mScaleListener = new OnScaleGestureListener() {
@Override
public boolean onScale(ScaleGestureDetector detector) {
mListener.onScale(detector.getScaleFactor(), detector.getFocusX(), detector.getFocusY());
return true;
}
@Override
public boolean onScaleBegin(ScaleGestureDetector detector) {
return true;
}
@Override
public void onScaleEnd(ScaleGestureDetector detector) {
// NO-OP
}
};
public FroyoDetector(Context context) {
super(context);
mDetector = new ScaleGestureDetector(context, mScaleListener);
}
@Override
public boolean isScaling() {
return mDetector.isInProgress();
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
mDetector.onTouchEvent(ev);
return super.onTouchEvent(ev);
}
}
}
10.MainActivity
package com.suo.myimage;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerHorizontal="true" android:layout_centerVertical="true" android:text="@string/hello_world" /> <com.suo.image.ScaleView android:layout_width="match_parent" android:layout_height="match_parent" android:src="@drawable/a"/> </RelativeLayout>
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