android 中viewpager+fragment仿微信底部TAG完美渐变

package com.Sing.weixin; import java.lang.reflect.Field; import java.util.ArrayList; import java.util.List; import android.annotation.SuppressLint; import android.os.Bundle; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentActivity; import android.support.v4.app.FragmentManager; import android.support.v4.app.FragmentPagerAdapter; import android.support.v4.view.ViewPager; import android.support.v4.view.ViewPager.OnPageChangeListener; import android.view.View; import android.view.View.OnClickListener; import android.view.ViewConfiguration; @SuppressLint("NewApi") public class MainActivity extends FragmentActivity implements OnPageChangeListener, OnClickListener { private ViewPager mViewPager; // 选项卡一Fragment private FrgReturnVisit returnVisit; // 选项卡一Fragment private FrgMicroVisit microVisit; private List<ChangeColorIconWithTextView> mTabIndicator = new ArrayList<ChangeColorIconWithTextView>(); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); setOverflowShowingAlways(); mViewPager = (ViewPager) findViewById(R.id.id_viewpager); mViewPager.setAdapter(new MyPagerAdapter(getSupportFragmentManager())); initTabIndicator(); mViewPager.setOnPageChangeListener(this); } private void initTabIndicator() { ChangeColorIconWithTextView one = (ChangeColorIconWithTextView) findViewById(R.id.id_indicator_one); ChangeColorIconWithTextView two = (ChangeColorIconWithTextView) findViewById(R.id.id_indicator_two); mTabIndicator.add(one); mTabIndicator.add(two); one.setOnClickListener(this); two.setOnClickListener(this); one.setIconAlpha(1.0f); } @Override public void onPageSelected(int arg0) { } @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { if (positionOffset > 0) { ChangeColorIconWithTextView left = mTabIndicator.get(position); ChangeColorIconWithTextView right = mTabIndicator.get(position + 1); left.setIconAlpha(1 - positionOffset); right.setIconAlpha(positionOffset); } } @Override public void onPageScrollStateChanged(int state) { } @Override public void onClick(View v) { resetOtherTabs(); switch (v.getId()) { case R.id.id_indicator_one: mTabIndicator.get(0).setIconAlpha(1.0f); mViewPager.setCurrentItem(0, false); break; case R.id.id_indicator_two: mTabIndicator.get(1).setIconAlpha(1.0f); mViewPager.setCurrentItem(1, false); break; } } /** * 重置其他的Tab */ private void resetOtherTabs() { for (int i = 0; i < mTabIndicator.size(); i++) { mTabIndicator.get(i).setIconAlpha(0); } } private void setOverflowShowingAlways() { try { // true if a permanent menu key is present, false otherwise. ViewConfiguration config = ViewConfiguration.get(this); Field menuKeyField = ViewConfiguration.class.getDeclaredField("sHasPermanentMenuKey"); menuKeyField.setAccessible(true); menuKeyField.setBoolean(config, false); } catch (Exception e) { e.printStackTrace(); } } public class MyPagerAdapter extends FragmentPagerAdapter { public MyPagerAdapter(FragmentManager fm) { super(fm); } private final String[] titles = { "选项一", "选项二"}; @Override public CharSequence getPageTitle(int position) { return titles[position]; } @Override public int getCount() { return titles.length; } @Override public Fragment getItem(int position) { switch (position) { case 0: if (returnVisit == null) { returnVisit = new FrgReturnVisit(); } return returnVisit; case 1: if (microVisit == null) { microVisit = new FrgMicroVisit(); } return microVisit; default: return null; } } } }

package com.Sing.weixin; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Bitmap; import android.graphics.Bitmap.Config; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.PorterDuff; import android.graphics.PorterDuffXfermode; import android.graphics.Rect; import android.graphics.drawable.BitmapDrawable; import android.os.Bundle; import android.os.Looper; import android.os.Parcelable; import android.util.AttributeSet; import android.util.TypedValue; import android.view.View; public class ChangeColorIconWithTextView extends View { private Bitmap mBitmap; private Canvas mCanvas; private Paint mPaint; /** * 颜色 */ private int mColor = 0xFF45C01A; /** * 透明度 0.0-1.0 */ private float mAlpha = 0f; /** * 图标 */ private Bitmap mIconBitmap; /** * 限制绘制icon的范围 */ private Rect mIconRect; /** * icon底部文本 */ private String mText = "demo"; private int mTextSize = (int) TypedValue.applyDimension( TypedValue.COMPLEX_UNIT_SP, 10, getResources().getDisplayMetrics()); private Paint mTextPaint; private Rect mTextBound = new Rect(); public ChangeColorIconWithTextView(Context context) { super(context); } /** * 初始化自定义属性值 * * @param context * @param attrs */ public ChangeColorIconWithTextView(Context context, AttributeSet attrs) { super(context, attrs); // 获取设置的图标 TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.ChangeColorIconView); int n = a.getIndexCount(); for (int i = 0; i < n; i++) { int attr = a.getIndex(i); switch (attr) { case R.styleable.ChangeColorIconView_icon: BitmapDrawable drawable = (BitmapDrawable) a.getDrawable(attr); mIconBitmap = drawable.getBitmap(); break; case R.styleable.ChangeColorIconView_color: mColor = a.getColor(attr, 0x45C01A); break; case R.styleable.ChangeColorIconView_text: mText = a.getString(attr); break; case R.styleable.ChangeColorIconView_text_size: mTextSize = (int) a.getDimension(attr, TypedValue .applyDimension(TypedValue.COMPLEX_UNIT_SP, 10, getResources().getDisplayMetrics())); break; } } a.recycle(); mTextPaint = new Paint(); mTextPaint.setTextSize(mTextSize); mTextPaint.setColor(0xff555555); // 得到text绘制范围 mTextPaint.getTextBounds(mText, 0, mText.length(), mTextBound); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); // 得到绘制icon的宽 int bitmapWidth = Math.min(getMeasuredWidth() - getPaddingLeft() - getPaddingRight(), getMeasuredHeight() - getPaddingTop() - getPaddingBottom() - mTextBound.height()); int left = getMeasuredWidth() / 2 - bitmapWidth / 2; int top = (getMeasuredHeight() - mTextBound.height()) / 2 - bitmapWidth / 2; // 设置icon的绘制范围 mIconRect = new Rect(left, top, left + bitmapWidth, top + bitmapWidth); } @Override protected void onDraw(Canvas canvas) { int alpha = (int) Math.ceil((255 * mAlpha)); canvas.drawBitmap(mIconBitmap, null, mIconRect, null); setupTargetBitmap(alpha); drawSourceText(canvas, alpha); drawTargetText(canvas, alpha); canvas.drawBitmap(mBitmap, 0, 0, null); } private void setupTargetBitmap(int alpha) { mBitmap = Bitmap.createBitmap(getMeasuredWidth(), getMeasuredHeight(), Config.ARGB_8888); mCanvas = new Canvas(mBitmap); mPaint = new Paint(); mPaint.setColor(mColor); mPaint.setAntiAlias(true); mPaint.setDither(true); mPaint.setAlpha(alpha); mCanvas.drawRect(mIconRect, mPaint); mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN)); mPaint.setAlpha(255); mCanvas.drawBitmap(mIconBitmap, null, mIconRect, mPaint); } private void drawSourceText(Canvas canvas, int alpha) { mTextPaint.setTextSize(mTextSize); mTextPaint.setColor(0xff333333); mTextPaint.setAlpha(255 - alpha); canvas.drawText(mText, mIconRect.left + mIconRect.width() / 2 - mTextBound.width() / 2, mIconRect.bottom + mTextBound.height(), mTextPaint); } private void drawTargetText(Canvas canvas, int alpha) { mTextPaint.setColor(mColor); mTextPaint.setAlpha(alpha); canvas.drawText(mText, mIconRect.left + mIconRect.width() / 2 - mTextBound.width() / 2, mIconRect.bottom + mTextBound.height(), mTextPaint); } public void setIconAlpha(float alpha) { this.mAlpha = alpha; invalidateView(); } private void invalidateView() { if (Looper.getMainLooper() == Looper.myLooper()) { invalidate(); } else { postInvalidate(); } } public void setIconColor(int color) { mColor = color; } public void setIcon(int resId) { this.mIconBitmap = BitmapFactory.decodeResource(getResources(), resId); if (mIconRect != null) invalidateView(); } public void setIcon(Bitmap iconBitmap) { this.mIconBitmap = iconBitmap; if (mIconRect != null) invalidateView(); } private static final String INSTANCE_STATE = "instance_state"; private static final String STATE_ALPHA = "state_alpha"; @Override protected Parcelable onSaveInstanceState() { Bundle bundle = new Bundle(); bundle.putParcelable(INSTANCE_STATE, super.onSaveInstanceState()); bundle.putFloat(STATE_ALPHA, mAlpha); return bundle; } @Override protected void onRestoreInstanceState(Parcelable state) { if (state instanceof Bundle) { Bundle bundle = (Bundle) state; mAlpha = bundle.getFloat(STATE_ALPHA); super.onRestoreInstanceState(bundle.getParcelable(INSTANCE_STATE)); } else { super.onRestoreInstanceState(state); } } }

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