Android中View跟随手指滑动效果的实例代码

public class MoveView extends View { 
 private int lastX, lastY; 
 public MoveView(Context context, @Nullable AttributeSet attrs) { 
 super(context, attrs); 
 } 
 public MoveView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) { 
 super(context, attrs, defStyleAttr); 
 } 
 public MoveView(Context context) { 
 super(context); 
 } 
 public boolean onTouchEvent(MotionEvent event) { 
 int x = (int) event.getX(); 
 int y = (int) event.getY(); 
 switch (event.getAction()) { 
 case MotionEvent.ACTION_DOWN: 
 lastX = x; 
 lastY = y; 
 break; 
 case MotionEvent.ACTION_MOVE: 
 int offsetX = x - lastX;//计算滑动的距离 
 int offsetY = y - lastY; 
 //重新放置新的位置 
 layout(getLeft() + offsetX, getTop() + offsetY, getRight() + offsetX, getBottom() + offsetY); 
 } 
 return true; 
 } 
} 

 public boolean onTouchEvent(MotionEvent event) { 
 int x = (int) event.getX(); 
 int y = (int) event.getY(); 
 switch (event.getAction()) { 
 case MotionEvent.ACTION_DOWN: 
 lastX = x; 
 lastY = y; 
 break; 
 case MotionEvent.ACTION_MOVE: 
 int offsetX = x - lastX;//计算滑动的距离 
 int offsetY = y - lastY; 
 //重新放置新的位置 
// layout(getLeft() + offsetX, getTop() + offsetY, getRight() + offsetX, getBottom() + offsetY); 
 offsetLeftAndRight(offsetX); 
 offsetTopAndBottom(offsetY); 
 } 
 return true; 
 } 

public boolean onTouchEvent(MotionEvent event) { 
 int x = (int) event.getX(); 
 int y = (int) event.getY(); 
 switch (event.getAction()) { 
 case MotionEvent.ACTION_DOWN: 
 lastX = x; 
 lastY = y; 
 break; 
 case MotionEvent.ACTION_MOVE: 
 int offsetX = x - lastX;//计算滑动的距离 
 int offsetY = y - lastY; 
 //重新放置新的位置 
// layout(getLeft() + offsetX, getTop() + offsetY, getRight() + offsetX, getBottom() + offsetY); 
// offsetLeftAndRight(offsetX); 
// offsetTopAndBottom(offsetY); 
 LinearLayout.LayoutParams layoutParams = (LinearLayout.LayoutParams) getLayoutParams(); 
 layoutParams.leftMargin = getLeft()+offsetX; 
 layoutParams.topMargin = getTop() +offsetY; 
 setLayoutParams(layoutParams); 
 } 
 return true; 
 } 

public class MoveView extends View { 
 private Scroller mScroller; 
 public MoveView(Context context, @Nullable AttributeSet attrs) { 
 super(context, attrs); 
 mScroller = new Scroller(context); 
 } 
 public MoveView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) { 
 super(context, attrs, defStyleAttr); 
 } 
 public MoveView(Context context) { 
 super(context); 
 } 
 //重写computeScroll方法 
 @Override 
 public void computeScroll() { //view在onDraw的时候会调用此方法 
 super.computeScroll(); 
 if (mScroller.computeScrollOffset()) { 
 ((View) getParent()).scrollTo(mScroller.getCurrX(), mScroller.getCurrY()); 
 invalidate(); 
 } 
 } 
 //在外部调用这个方法即可 
 public void smoothScrollTo(int destX, int destY) { 
 int scrollX = getScrollX(); 
 int delta = destX - scrollX; 
 mScroller.startScroll(scrollX, 0, delta,0 ,6000); 
 invalidate(); 
 } 
}