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?
这是一个合适的工作解决方案，我已经测试过了:
例如：
private void expand(View v) {
v.setVisibility(View.VISIBLE);
v.measure(View.MeasureSpec.makeMeasureSpec(PARENT_VIEW.getWidth(), View.MeasureSpec.EXACTLY),
View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED));
final int targetHeight = v.getMeasuredHeight();
mAnimator = slideAnimator(0, targetHeight);
mAnimator.setDuration(800);
mAnimator.start();
}
崩溃:
private void collapse(View v) {
int finalHeight = v.getHeight();
mAnimator = slideAnimator(finalHeight, 0);
mAnimator.addListener(new Animator.AnimatorListener() {
@Override
public void onAnimationStart(Animator animator) {
}
@Override
public void onAnimationEnd(Animator animator) {
//Height=0, but it set visibility to GONE
llDescp.setVisibility(View.GONE);
}
@Override
public void onAnimationCancel(Animator animator) {
}
@Override
public void onAnimationRepeat(Animator animator) {
}
});
mAnimator.start();
}
动画师的值:
private ValueAnimator slideAnimator(int start, int end) {
ValueAnimator mAnimator = ValueAnimator.ofInt(start, end);
mAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator valueAnimator) {
//Update Height
int value = (Integer) valueAnimator.getAnimatedValue();
ViewGroup.LayoutParams layoutParams = llDescp.getLayoutParams();
layoutParams.height = value;
v.setLayoutParams(layoutParams);
}
});
return mAnimator;
}
视图v是要被动画的视图，PARENT_VIEW是包含该视图的容器视图。
我看到这个问题很受欢迎，所以我发布了我的实际解决方案。主要的优点是你不需要知道扩展的高度来应用动画，一旦视图被扩展，它会在内容改变时适应高度。这对我来说很有效。
public static void expand(final View v) {
int matchParentMeasureSpec = View.MeasureSpec.makeMeasureSpec(((View) v.getParent()).getWidth(), View.MeasureSpec.EXACTLY);
int wrapContentMeasureSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
v.measure(matchParentMeasureSpec, wrapContentMeasureSpec);
final int targetHeight = v.getMeasuredHeight();
// Older versions of android (pre API 21) cancel animations for views with a height of 0.
v.getLayoutParams().height = 1;
v.setVisibility(View.VISIBLE);
Animation a = new Animation()
{
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
v.getLayoutParams().height = interpolatedTime == 1
? LayoutParams.WRAP_CONTENT
: (int)(targetHeight * interpolatedTime);
v.requestLayout();
}
@Override
public boolean willChangeBounds() {
return true;
}
};
// Expansion speed of 1dp/ms
a.setDuration((int)(targetHeight / v.getContext().getResources().getDisplayMetrics().density));
v.startAnimation(a);
}
public static void collapse(final View v) {
final int initialHeight = v.getMeasuredHeight();
Animation a = new Animation()
{
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
if(interpolatedTime == 1){
v.setVisibility(View.GONE);
}else{
v.getLayoutParams().height = initialHeight - (int)(initialHeight * interpolatedTime);
v.requestLayout();
}
}
@Override
public boolean willChangeBounds() {
return true;
}
};
// Collapse speed of 1dp/ms
a.setDuration((int)(initialHeight / v.getContext().getResources().getDisplayMetrics().density));
v.startAnimation(a);
}
正如@Jefferson在评论中提到的，你可以通过改变动画的持续时间(以及速度)来获得更流畅的动画。目前，它已设置为1dp/ms的速度
你可以稍微改变一下使用ViewPropertyAnimator。若要折叠，请将视图缩放到1像素的高度，然后隐藏它。展开，显示它，然后展开到它的高度。
private void collapse(final View view) {
view.setPivotY(0);
view.animate().scaleY(1/view.getHeight()).setDuration(1000).withEndAction(new Runnable() {
@Override public void run() {
view.setVisibility(GONE);
}
});
}
private void expand(View view, int height) {
float scaleFactor = height / view.getHeight();
view.setVisibility(VISIBLE);
view.setPivotY(0);
view.animate().scaleY(scaleFactor).setDuration(1000);
}
枢轴告诉视图从哪里开始缩放，默认是在中间。持续时间是可选的(默认= 1000)。你也可以设置插值器来使用，比如.setInterpolator(new accelerateeraderateinterpolator ())
展开/折叠视图的最佳解决方案:
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
View view = buttonView.getId() == R.id.tb_search ? fSearch : layoutSettings;
transform(view, 200, isChecked
? ViewGroup.LayoutParams.WRAP_CONTENT
: 0);
}
public static void transform(final View v, int duration, int targetHeight) {
int prevHeight = v.getHeight();
v.setVisibility(View.VISIBLE);
ValueAnimator animator;
if (targetHeight == ViewGroup.LayoutParams.WRAP_CONTENT) {
v.measure(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
animator = ValueAnimator.ofInt(prevHeight, v.getMeasuredHeight());
} else {
animator = ValueAnimator.ofInt(prevHeight, targetHeight);
}
animator.addUpdateListener(animation -> {
v.getLayoutParams().height = (animation.getAnimatedFraction() == 1.0f)
? targetHeight
: (int) animation.getAnimatedValue();
v.requestLayout();
});
animator.setInterpolator(new LinearInterpolator());
animator.setDuration(duration);
animator.start();
}
