使用OnGestureListener。为了提供平滑的滚动效果,创建一个Scroller(在您的自定义视图中)。当手势侦听器检测到fling事件时,设置Scroller。然后,重写您的自定义视图的computeScroll()方法。
查看此示例以了解如何实现它。
int lastX;
int lastY;
Scroller scroller;
@Override
public void computeScroll() {
if (scroller.computeScrollOffset()) {
if (!scrolledLastFrame) {
lastX = scroller.getStartX();
lastY = scroller.getStartY();
}
int dx = scroller.getCurrX() - lastX;
int dy = scroller.getCurrY() - lastY;
lastX = scroller.getCurrX();
lastY = scroller.getCurrY();
doScroll(dx, dy);
scrolledLastFrame = true;
} else {
scrolledLastFrame = false;
}
}
public void doFling(int startX, int startY, int velocityX, int velocityY,
int minX, int maxX, int minY, int maxY) {
scroller.fling(startX, startY, velocityX, velocityY, minX, maxX, minY, maxY);
invalidate();
}
public void doScroll(int dx, int dy) {
currentX+=dx;
currentY+=dy;
invalidate();
}
private class ProgramGestureListener extends SimpleOnGestureListener {
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2,
float distanceX, float distanceY) {
doScroll(distanceX, distanceY);
return true;
}
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
int max_left = getMaxHorizontalScroll();
int max_top = getMaxVerticalScroll();
int min_left = getMinHorizontalScroll();
int min_top = getMinVerticalScroll();
int startX = getCurrentHorizontalScroll();
int startY = getCurrentVerticalScroll();
doFling(startX, startY, (int) -velocityX, (int) -velocityY,
min_left, max_left, min_top, max_top);
return true;
}
}