package com.imooc.dragviewtest;
import android.content.Context;
import android.graphics.Color;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Scroller;
public class DragView5 extends View {
private int lastX;
private int lastY;
private Scroller mScroller;
public DragView5(Context context) {
super(context);
ininView(context);
}
public DragView5(Context context, AttributeSet attrs) {
super(context, attrs);
ininView(context);
}
public DragView5(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
ininView(context);
}
private void ininView(Context context) {
setBackgroundColor(Color.BLUE);
// 初始化Scroller
mScroller = new Scroller(context);
}
@Override
public void computeScroll() {
super.computeScroll();
// 判断Scroller是否执行完毕
if (mScroller.computeScrollOffset()) {
((View) getParent()).scrollTo(
mScroller.getCurrX(),
mScroller.getCurrY());
// 通过重绘来不断调用computeScroll
invalidate();
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
int x = (int) event.getX();
int y = (int) event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
lastX = (int) event.getX();
lastY = (int) event.getY();
break;
case MotionEvent.ACTION_MOVE:
int offsetX = x - lastX;
int offsetY = y - lastY;
((View) getParent()).scrollBy(-offsetX, -offsetY);
break;
case MotionEvent.ACTION_UP:
// 手指离开时,执行滑动过程
View viewGroup = ((View) getParent());
mScroller.startScroll(
viewGroup.getScrollX(),
viewGroup.getScrollY(),
-viewGroup.getScrollX(),
-viewGroup.getScrollY());
invalidate();
break;
}
return true;
}
}