我喜欢通过Google+应用帖子滚动时出现的动画,但我不能工作了他们是如何实现它。
I like the animation that occurs when scrolling through posts in the Google+ app, but I can't work out how they achieve it.
都采用什么技术,他们似乎动画帖子?我不是在寻找的动画本身,只是我怎么会应用任何动画,以滚动的项目列表。
What techniques are employed to animate posts as they appear? I'm not looking for the animation itself, just how I'd apply any animation to a list of scrollable items.
感谢。
在某些测试中,我想我得到了类似的工作,事情;
After some testing I think I got something similar to work;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
final LinearLayout list = new LinearLayout(this);
list.setOrientation(LinearLayout.VERTICAL);
ScrollView scrollView = new ScrollView(this) {
Rect mRect = new Rect();
@Override
public void onLayout(boolean changed, int l, int t, int r, int b) {
super.onLayout(changed, l, t, r, b);
for (int i = 0; i < list.getChildCount(); ++i) {
View v = list.getChildAt(i);
// Tag initially visible Views as 'true'.
mRect.set(l, t, r, b);
v.setTag(getChildVisibleRect(v, mRect, null));
}
}
@Override
public void onScrollChanged(int l, int t, int oldl, int oldt) {
super.onScrollChanged(l, t, oldl, oldt);
for (int i = 0; i < list.getChildCount(); ++i) {
View v = list.getChildAt(i);
mRect.set(getLeft(), getTop(), getRight(), getBottom());
// If tag == 'false' and View is visible we know that
// View became visible during this scroll event.
if ((Boolean) v.getTag() == false
&& getChildVisibleRect(v, mRect, null)) {
AlphaAnimation anim = new AlphaAnimation(0, 1);
anim.setDuration(1000);
v.startAnimation(anim);
v.setTag(true);
}
}
}
};
scrollView.addView(list);
for (int i = 0; i < 20; ++i) {
TextView tv = new TextView(this);
tv.setText("Test");
tv.setTextSize(72);
tv.setTextColor(Color.WHITE);
tv.setBackgroundColor(Color.GRAY);
list.addView(tv);
}
setContentView(scrollView);
}
向下滚动列表应触发奥飞动漫,一旦新的的TextView
取值变得可见。
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