一般而言，要以很少的限制扩展触摸区域，请使用以下代码。
它使您可以将给view定ancestor视图内给定的触摸区域扩展给定expansion的像素数。您可以选择任何祖先，只要给定视图在祖先布局树中即可。
public static void expandTouchArea(final View view, final ViewGroup ancestor, final int expansion) {
ancestor.post(new Runnable() {
public void run() {
Rect bounds = getRelativeBounds(view, ancestor);
Rect expandedBounds = expand(bounds, expansion);
ancestor.setTouchDelegate(new TouchDelegate(expandedBounds, view));
}
private Rect getRelativeBounds(View view, ViewGroup ancestor) {
Point relativeLocation = getRelativeLocation(view, ancestor);
return new Rect(relativeLocation.x, relativeLocation.y,
relativeLocation.x + view.getWidth(),
relativeLocation.y + view.getHeight());
}
private Point getRelativeLocation(View view, ViewGroup ancestor) {
Point absoluteAncestorLocation = getAbsoluteLocation(ancestor);
Point absoluteViewLocation = getAbsoluteLocation(view);
return new Point(absoluteViewLocation.x - absoluteAncestorLocation.x,
absoluteViewLocation.y - absoluteAncestorLocation.y);
}
private Point getAbsoluteLocation(View view) {
int[] absoluteLocation = new int[2];
view.getLocationOnScreen(absoluteLocation);
return new Point(absoluteLocation[0], absoluteLocation[1]);
}
private Rect expand(Rect rect, int by) {
Rect expandedRect = new Rect(rect);
expandedRect.left -= by;
expandedRect.top -= by;
expandedRect.right += by;
expandedRect.bottom += by;
return expandedRect;
}
});
}
适用的限制：
- 触摸区域不能超出视图祖先的范围，因为祖先必须能够捕获触摸事件才能将其转发到视图。
- 只能将一个
TouchDelegate设置为ViewGroup。如果要使用多个触摸代表，请选择不同的祖先或使用如如何使用多个TouchDelegate中所述的组成的触摸代表。
