假设我有一个垂直线性布局:
[v1]
[v2]
默认情况下，v1已经可见= GONE。我想用一个展开动画显示v1，同时下推v2。
我是这样做的:
Animation a = new Animation()
{
int initialHeight;
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
final int newHeight = (int)(initialHeight * interpolatedTime);
v.getLayoutParams().height = newHeight;
v.requestLayout();
}
@Override
public void initialize(int width, int height, int parentWidth, int parentHeight) {
super.initialize(width, height, parentWidth, parentHeight);
initialHeight = height;
}
@Override
public boolean willChangeBounds() {
return true;
}
};
但是用这个解决方案，当动画开始时我有一个眨眼。我认为这是由于v1在应用动画之前显示全尺寸。
用javascript，这是一行jQuery!android有什么简单的方法吗?
public static void expand(final View v, int duration, int targetHeight) {
v.measure(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
v.getLayoutParams().height = 0;
v.setVisibility(View.VISIBLE);
ValueAnimator valueAnimator = ValueAnimator.ofInt(0, targetHeight);
valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
v.getLayoutParams().height = (int) animation.getAnimatedValue();
v.requestLayout();
}
});
valueAnimator.setInterpolator(new DecelerateInterpolator());
valueAnimator.setDuration(duration);
valueAnimator.start();
}
public static void collapse(final View v, int duration, int targetHeight) {
ValueAnimator valueAnimator = ValueAnimator.ofInt(0, targetHeight);
valueAnimator.setInterpolator(new DecelerateInterpolator());
valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
v.getLayoutParams().height = (int) animation.getAnimatedValue();
v.requestLayout();
}
});
valueAnimator.setInterpolator(new DecelerateInterpolator());
valueAnimator.setDuration(duration);
valueAnimator.start();
}
我今天也遇到了同样的问题，我想这个问题的真正解决方案是这样的
<LinearLayout android:id="@+id/container"
android:animateLayoutChanges="true"
...
/>
您必须为所有涉及移位的最顶层布局设置此属性。如果你现在将一个布局的可见性设置为GONE，另一个将在消失的布局释放它时占据空间。会有一个默认的动画，这是某种“淡出”，但我认为你可以改变这个-但最后一个我没有测试，现在。
如果在RecyclerView项目中使用这个，在onBindViewHolder中设置视图的可见性来展开/折叠，并调用notifyItemChanged(position)来触发转换。
override fun onBindViewHolder(holder: ItemViewHolder, position: Int) {
...
holder.list.visibility = data[position].listVisibility
holder.expandCollapse.setOnClickListener {
data[position].listVisibility = if (data[position].listVisibility == View.GONE) View.VISIBLE else View.GONE
notifyItemChanged(position)
}
}
如果你在onBindViewHolder中执行昂贵的操作，你可以使用notifyItemChanged(位置，有效载荷)优化部分更改
private const val UPDATE_LIST_VISIBILITY = 1
override fun onBindViewHolder(holder: ItemViewHolder, position: Int, payloads: MutableList<Any>) {
if (payloads.contains(UPDATE_LIST_VISIBILITY)) {
holder.list.visibility = data[position].listVisibility
} else {
onBindViewHolder(holder, position)
}
}
override fun onBindViewHolder(holder: ItemViewHolder, position: Int) {
...
holder.list.visibility = data[position].listVisibility
holder.expandCollapse.setOnClickListener {
data[position].listVisibility = if (data[position].listVisibility == View.GONE) View.VISIBLE else View.GONE
notifyItemChanged(position, UPDATE_LIST_VISIBILITY)
}
}
