Android 指针钟表实现

public class HandClockView extends View implements Runnable { private static final String NAMESPACE = "http://www.pro.dev.com/common"; private static final String CLOCK_FACE="colckFace"; private static final String HAND_CENTER_WIDTH_SCALE = "handCenterWidthScale"; private static final String HAND_CENTER_HEIGHT_SCALE = "handCenterHeightScale"; private static final String SCALE = "scale"; private static final String HOUR_HAND_SIZE = "hourHandSize"; private static final String MINUTE_HAND_SIZE = "minuteHandSize";  private Bitmap clockFace; private int clockFaceId; private float centerX; private float centerY; private float handCenterWidthScale; private float handCenterHeightScale; private float scale; private int hourHandSize; private int minuteHandSize; private Handler handler = new Handler();   public HandClockView(Context context) {  super(context); }  public HandClockView(Context context, AttributeSet attrs) {  super(context, attrs);  init(attrs); } public HandClockView(Context context, AttributeSet attrs, int defStyle) {  super(context, attrs, defStyle);  init(attrs); }  private void init(AttributeSet attrs) {  clockFaceId = attrs.getAttributeResourceValue(NAMESPACE, CLOCK_FACE, 0);  Log.e("zhang.xiao", "clockFaceId=" + clockFaceId);  if (clockFaceId > 0) {   clockFace = BitmapFactory.decodeResource(getResources(), clockFaceId);  }  Log.e("zhang.xiao", "clockFace is null " + String.valueOf(clockFace == null));  handCenterWidthScale = attrs.getAttributeFloatValue(NAMESPACE, HAND_CENTER_WIDTH_SCALE, clockFace.getWidth() / 2);  handCenterHeightScale = attrs.getAttributeFloatValue(NAMESPACE, HAND_CENTER_HEIGHT_SCALE, clockFace.getHeight() / 2);  scale = attrs.getAttributeFloatValue(NAMESPACE, SCALE, 0);  hourHandSize = (int) (scale * attrs.getAttributeIntValue(NAMESPACE, HOUR_HAND_SIZE, 0));  minuteHandSize = (int) (scale * attrs.getAttributeIntValue(NAMESPACE, MINUTE_HAND_SIZE, 0)); }  @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {  super.onMeasure(widthMeasureSpec, heightMeasureSpec);  setMeasuredDimension((int)(clockFace.getWidth() * scale), (int)(clockFace.getHeight() * scale)); }  @Override public void run() {  invalidate();  handler.postDelayed(this, 60 * 1000); }  @Override protected void onDraw(Canvas canvas) {  super.onDraw(canvas);    Paint paint = new Paint();  Rect src = new Rect();  src.left = 0;  src.top = 0;  src.right = clockFace.getWidth();  src.bottom = clockFace.getHeight();    Rect target = new Rect();  target.left = 0;  target.top = 0;  target.right = (int) (src.right * scale);  target.bottom = (int) (src.bottom * scale);    canvas.drawBitmap(clockFace, src, target, paint);    centerX = clockFace.getWidth() * handCenterWidthScale * scale;  centerY = clockFace.getHeight() * handCenterHeightScale * scale;    canvas.drawCircle(centerX, centerY, 5, paint);  paint.setStrokeWidth(3);    Calendar cal = Calendar.getInstance();  int minute = cal.get(Calendar.MINUTE);  int hour = cal.get(Calendar.HOUR);  int second = cal.get(Calendar.SECOND);  Log.e("zhang.xiao", "hour=" + hour);  Log.e("zhang.xiao", "minute=" + minute);  double minuteRadian = Math.toRadians((360 - ((minute * 6) - 90)) % 360);  double hourRadian = Math.toRadians(((360 - ((hour * 30) - 90)) % 360) - (30 * minute / 60));    canvas.drawLine(centerX, centerY, (int) (centerX + minuteHandSize * Math.cos(minuteRadian)),     (int) (centerY - Math.sin(minuteRadian) * minuteHandSize), paint);    paint.setStrokeWidth(4);  canvas.drawLine(centerX, centerY, (int) (centerX + hourHandSize * Math.cos(hourRadian)),     (int) (centerY - Math.sin(hourRadian) * hourHandSize), paint);  handler.postDelayed(this, (60 - second) * 1000); }  @Override protected void onDetachedFromWindow() {  super.onDetachedFromWindow();  Log.e("zhang.xiao", "onDetachedFromWindow"); }}