默认滚动视图的衰落边缘是可见的,只有当它是可能在该方向上滚动。我怎样才能使它在任何时候都可见?
by default scrollview's fading edge is visible only if it is possible to scroll in that direction. How can I make it visible at all times?
我不想把任何可绘制在顶部或类似的东西。我想用它内建的衰落边缘,可能是压倒一切的一些滚动型的功能来完成。
I don't want to put any drawables on top or something like that. I want to accomplish it using the builtin fading edge, probably by overriding some scrollview functions.
在此先感谢
是的,滚动型延伸并覆盖这些方法(基于甜甜圈-release2):
Yes, extend ScrollView and override these methods (based on Donut-release2):
@Override
protected float getTopFadingEdgeStrength() {
if (getChildCount() == 0) {
return 0.0f;
}
return 1.0f;
}
@Override
protected float getBottomFadingEdgeStrength() {
if (getChildCount() == 0) {
return 0.0f;
}
return 1.0f;
}
有关比较的缘故,这是原来的code,从而缩短了衰退的边缘,你去接近列表的末尾:
For comparison's sake, this is the original code, which shortens the fading edge as you get close to the end of the list:
@Override
protected float getTopFadingEdgeStrength() {
if (getChildCount() == 0) {
return 0.0f;
}
final int length = getVerticalFadingEdgeLength();
if (mScrollY < length) {
return mScrollY / (float) length;
}
return 1.0f;
}
@Override
protected float getBottomFadingEdgeStrength() {
if (getChildCount() == 0) {
return 0.0f;
}
final int length = getVerticalFadingEdgeLength();
final int bottomEdge = getHeight() - mPaddingBottom;
final int span = getChildAt(0).getBottom() - mScrollY - bottomEdge;
if (span < length) {
return span / (float) length;
}
return 1.0f;
}