我扩展了HorizontalScrollView
类以实现某些行为。在CustomHorizontalScrollView
内部的LinearLayout下,我只有2个子视图(让我们说ImageView
)。当用户向一个方向滚动超过50%时,我希望我的CustomHorizontalScrollView
自动滚动到同一方向的末端。这是我的实现方式:CustomHorizontalScrollView
类:
public class CustomHorizontalScrollView extends HorizontalScrollView {
private static float downCoordinates = -1;
private static float upCoordinates = -1;
private static int currentPosition = 0;
public CustomHorizontalScrollView(Context ctx) {
super(ctx);
}
public CustomHorizontalScrollView(Context ctx, AttributeSet attrs) {
super(ctx, attrs);
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
if (ev.getAction() == MotionEvent.ACTION_DOWN && downCoordinates == -1) {
downCoordinates = ev.getX();
}
else if (ev.getAction() == MotionEvent.ACTION_UP && upCoordinates == -1) {
upCoordinates = ev.getX();
int scrollViewWidth = this.getMeasuredWidth();
double dist = downCoordinates - upCoordinates;
if (Math.abs(dist) > scrollViewWidth / 2) {
//this.setSmoothScrollingEnabled(true);
// Going forwards
if (dist > 0) {
int max = ((LinearLayout)this.getChildAt(0)).getChildAt(1).getMeasuredWidth();
currentPosition = max;
this.scrollTo(max, 0);
}
// Going backwards
else {
currentPosition = 0;
this.scrollTo(0, 0);
}
}
// reseting the saved Coordinates
downCoordinates = -1;
upCoordinates = -1;
}
return super.onTouchEvent(ev);
}
}
直到这里-一切正常。问题是我希望自动滚动能够顺利完成,所以我尝试使用
smoothScrollTo
函数而不是scrollTo
函数,但是随后什么也没有发生(就像没有自动滚动一样)。我试图宣布这一点:this.setSmoothScrollingEnabled(true);
但也没有成功。
最佳答案
你有尝试过吗?
this.post(new Runnable() {
public void run() {
this.smoothScrollTo(0, this.getBottom());
}
});