Android 8.1 Launcher3实现动态指针时钟功能

import android.content.Context;
import android.graphics.Bitmap;
import android.os.Handler;
import android.os.Message;
import com.android.launcher3.ItemInfo;
import com.android.launcher3.LauncherSettings;
import com.android.launcher3.ShortcutInfo;
import com.android.launcher3.util.LogUtil;
public class DeskClockUtil {
  private OnDeskClockIconChangeListener mListener;
  private ItemInfo mItemInfo;
  private boolean mIsResume;
  private Handler mHandler = new Handler() {
    @Override
    public void handleMessage(Message msg) {
      super.handleMessage(msg);
      if (msg.what == 100) {
        Message msg1 = new Message();
        msg1.what = 100;
        msg1.obj = msg.obj;
        mHandler.sendMessageDelayed(msg1, 60000);
        if (mListener != null && mItemInfo != null) {
          mListener.onChange(IconUtil.getDeskClockIcon((Context) msg.obj), mItemInfo);
        }
      }
    }
  };
  private static DeskClockUtil sInstance;
  private DeskClockUtil() {
  }
  public static DeskClockUtil getInstance() {
    if (sInstance == null) {
      sInstance = new DeskClockUtil();
    }
    return sInstance;
  }
  private void refresh(Context context) {
    if (mListener != null && mItemInfo != null) {
      mListener.onChange(IconUtil.getDeskClockIcon(context), mItemInfo);
    }
    if (mHandler.hasMessages(100)) {
      mHandler.removeMessages(100);
    }
    Message msg = new Message();
    msg.what = 100;
    msg.obj = context;
    mHandler.sendMessageDelayed(msg,
        1000 * (60 - Integer.parseInt(DateUtils.getCurrentSecond())));
  }
  public void onResume(Context context) {
    mIsResume = true;
    refresh(context);
  }
  public void onPause() {
    mIsResume = false;
    mHandler.removeMessages(100);
  }
  public void setListener(OnDeskClockIconChangeListener listener, ItemInfo info, Context context) {
    if (!(info instanceof ShortcutInfo)) {
      return;
    }
    String pkg = null;
    if (info.getIntent() != null && info.getIntent().getComponent() != null) {
      pkg = info.getIntent().getComponent().getPackageName();
    }
    if (!"com.android.deskclock".equals(pkg) || info.itemType == LauncherSettings.Favorites.ITEM_TYPE_DEEP_SHORTCUT) {
      return;
    }
    mListener = listener;
    mItemInfo = info;
    if (mIsResume) {
      refresh(context);
    }
  }
  public interface OnDeskClockIconChangeListener {
    void onChange(Bitmap icon, ItemInfo info);
  }
}

import android.content.Context;
import android.graphics.*;
import com.android.launcher3.R;
public class IconUtil {
  private static final String TAG = "IconUtil";
  private static Bitmap getBitmap(Context context, int res) {
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inPreferredConfig = Bitmap.Config.ARGB_4444;
    return BitmapFactory.decodeResource(context.getResources(), res, options);
  }
  public static Bitmap getDeskClockIcon(Context context) {
    // 添加一个带表盘的背景图
    Bitmap empty = getBitmap(context, R.drawable.icon_time);
    int x = empty.getWidth();
    int y = empty.getHeight();
    Bitmap deskClock = Bitmap.createBitmap(x, y, Bitmap.Config.ARGB_4444);
    Canvas canvas = new Canvas(deskClock);
    Paint paint = new Paint();
    paint.setAntiAlias(true);
    canvas.drawBitmap(empty, 0, 0, paint);
    //设置圆角
    paint.setStrokeCap(Paint.Cap.ROUND);
    paint.setStrokeWidth(5);
    paint.setColor(context.getResources().getColor(R.color.deskclock_time));
    // 时针的长度
    int radius = 35;
    // 圆心的x y 坐标
    int cx = x / 2;
    int cy = y / 2;
    int hour = Integer.parseInt(DateUtils.getCurrentHour());
    int min = Integer.parseInt(DateUtils.getCurrentMin());
    //时针的角度，这里是整点的角度。因为0°是从3点开始，所以这里减90°，从9点开始计算角度
    int drgeeHour = hour * 30 - 90;
    if (drgeeHour < 0) {
      drgeeHour += 360;
    }
    // 加上时针在两个整点之间的角度，一分钟在分针上是6°，在时针上是min * 6 / 12
    drgeeHour += min * 6 / 12;
    //时针 针尖的x y坐标，相当于已知圆心坐标和半径，求圆上任意一点的坐标
    int xHour = (int) (cx + radius * Math.cos(drgeeHour * 3.14 / 180));
    int yHour = (int) (cy + radius * Math.sin(drgeeHour * 3.14 / 180));
    canvas.drawLine(xHour, yHour, cx, cy, paint);
    //分针的长度
    radius = 45;
    paint.setStrokeWidth(3);
    paint.setColor(Color.RED);
    //分针的角度
    int drgeeMin = min * 6 - 90;
    if (drgeeMin < 0) {
      drgeeMin += 360;
    }
    //分针 针尖的x y坐标
    int x1 = (int) (cx + radius * Math.cos(drgeeMin * Math.PI / 180));
    int y1 = (int) (cy + radius * Math.sin(drgeeMin * Math.PI / 180));
    canvas.drawLine(x1, y1, cx, cy, paint);
    return deskClock;
  }
}

import java.text.SimpleDateFormat;
public class DateUtils {
  public static String getCurrentDay() {
    SimpleDateFormat format = new SimpleDateFormat("dd");
    Long t = new Long(System.currentTimeMillis());
    String d = format.format(t);
    return d;
  }
  public static String getCurrentSecond() {
    SimpleDateFormat format = new SimpleDateFormat("ss");
    Long t = new Long(System.currentTimeMillis());
    String d = format.format(t);
    return d;
  }
  public static String getCurrentMin() {
    SimpleDateFormat format = new SimpleDateFormat("mm");
    Long t = new Long(System.currentTimeMillis());
    String d = format.format(t);
    return d;
  }
  public static String getCurrentHour() {
    SimpleDateFormat format = new SimpleDateFormat("HH");
    Long t = new Long(System.currentTimeMillis());
    String d = format.format(t);
    return d;
  }
}

private void applyIconAndLabel(Bitmap icon, ItemInfo info) {
    /* begin */
    setDeskClockIcon(info);
    /* end */
    applyIcon(icon, info);
    setText(info.title);
    if (info.contentDescription != null) {
      setContentDescription(info.isDisabled()
          ? getContext().getString(R.string.disabled_app_label, info.contentDescription)
          : info.contentDescription);
    }
  }
  private void setDeskClockIcon(ItemInfo info) {
    DeskClockUtil.getInstance().setListener(new DeskClockUtil.OnDeskClockIconChangeListener() {
      @Override
      public void onChange(Bitmap icon, ItemInfo info) {
        applyIcon(icon, info);
      }
    }, info, getContext());
  }
  private void applyIcon(Bitmap icon, ItemInfo info) {
    FastBitmapDrawable iconDrawable = DrawableFactory.get(getContext()).newIcon(icon, info);
    iconDrawable.setIsDisabled(info.isDisabled());
    setIcon(iconDrawable);
  }

@Override  protected void onResume() {
   ......
    /* begin */
    DeskClockUtil.getInstance().onResume(this);
    /* end */
    if (mLauncherCallbacks != null) {
      mLauncherCallbacks.onResume();
    }
  }

@Override
  protected void onPause() {
    // Ensure that items added to Launcher are queued until Launcher returns
    InstallShortcutReceiver.enableInstallQueue(InstallShortcutReceiver.FLAG_ACTIVITY_PAUSED);
    super.onPause();
    mPaused = true;
    mDragController.cancelDrag();
    mDragController.resetLastGestureUpTime();
    // We call onHide() aggressively. The custom content callbacks should be able to
    // debounce excess onHide calls.
    if (mWorkspace.getCustomContentCallbacks() != null) {
      mWorkspace.getCustomContentCallbacks().onHide();
    }
    if (mLauncherCallbacks != null) {
      mLauncherCallbacks.onPause();
    }
    /* begin */
    DeskClockUtil.getInstance().onPause();
    /* end */
  }