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?
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
我创建的版本中，你不需要指定布局高度，因此它更容易和更干净的使用。解决方案是在动画的第一帧中获取高度(至少在我的测试中是可用的)。通过这种方式，您可以为视图提供任意高度和底边距。
在构造函数中还有一个小hack -底部边距被设置为-10000，以便视图在转换之前保持隐藏(防止闪烁)。
public class ExpandAnimation extends Animation {
private View mAnimatedView;
private ViewGroup.MarginLayoutParams mViewLayoutParams;
private int mMarginStart, mMarginEnd;
public ExpandAnimation(View view) {
mAnimatedView = view;
mViewLayoutParams = (ViewGroup.MarginLayoutParams) view.getLayoutParams();
mMarginEnd = mViewLayoutParams.bottomMargin;
mMarginStart = -10000; //hide before viewing by settings very high negative bottom margin (hack, but works nicely)
mViewLayoutParams.bottomMargin = mMarginStart;
mAnimatedView.setLayoutParams(mViewLayoutParams);
}
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
super.applyTransformation(interpolatedTime, t);
//view height is already known when the animation starts
if(interpolatedTime==0){
mMarginStart = -mAnimatedView.getHeight();
}
mViewLayoutParams.bottomMargin = (int)((mMarginEnd-mMarginStart) * interpolatedTime)+mMarginStart;
mAnimatedView.setLayoutParams(mViewLayoutParams);
}
}
我采用了@LenaYan的解决方案，但它并没有正常工作
对我来说(因为它在折叠和/或扩展之前将视图转换为0高度视图)并做了一些更改。
现在它工作得很好，通过获取视图之前的高度并开始扩展这个大小。坍缩也是一样的。
你可以简单地复制和粘贴下面的代码:
public static void expand(final View v, int duration, int targetHeight) {
int prevHeight = v.getHeight();
v.setVisibility(View.VISIBLE);
ValueAnimator valueAnimator = ValueAnimator.ofInt(prevHeight, 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) {
int prevHeight = v.getHeight();
ValueAnimator valueAnimator = ValueAnimator.ofInt(prevHeight, 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();
}
用法:
//Expanding the View
expand(yourView, 2000, 200);
// Collapsing the View
collapse(yourView, 2000, 100);
很容易!
感谢LenaYan提供的初始代码!
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();
}
你可以使用Transition或Animator来改变要展开/折叠的部分的可见性，或者使用不同布局的ConstraintSet。
最简单的一个是使用motionLayout与2个不同的布局和constraintSets改变从一个布局到另一个按钮点击。可以在布局之间进行更改
val constraintSet = ConstraintSet()
constraintSet.clone(this, R.layout.layout_collapsed)
val transition = ChangeBounds()
transition.interpolator = AccelerateInterpolator(1.0f)
transition.setDuration(300)
TransitionManager.beginDelayedTransition(YOUR_VIEW, transition)
constraintSet.applyTo(YOUR_VIEW)
使用过渡api
RotateX.kt
我在gif中使用改变rotationX的过渡api创建了一个。
class RotateX : Transition {
@Keep
constructor() : super()
@Keep
constructor(context: Context, attrs: AttributeSet) : super(context, attrs)
override fun getTransitionProperties(): Array<String> {
return TRANSITION_PROPERTIES
}
override fun captureStartValues(transitionValues: TransitionValues) {
captureValues(transitionValues)
}
override fun captureEndValues(transitionValues: TransitionValues) {
captureValues(transitionValues)
}
override fun createAnimator(
sceneRoot: ViewGroup,
startValues: TransitionValues?,
endValues: TransitionValues?
): Animator? {
if (startValues == null || endValues == null) return null
val startRotation = startValues.values[PROP_ROTATION] as Float
val endRotation = endValues.values[PROP_ROTATION] as Float
if (startRotation == endRotation) return null
val view = endValues.view
// ensure the pivot is set
view.pivotX = view.width / 2f
view.pivotY = view.height / 2f
return ObjectAnimator.ofFloat(view, View.ROTATION_X, startRotation, endRotation)
}
private fun captureValues(transitionValues: TransitionValues) {
val view = transitionValues.view
if (view == null || view.width <= 0 || view.height <= 0) return
transitionValues.values[PROP_ROTATION] = view.rotationX
}
companion object {
private const val PROP_ROTATION = "iosched:rotate:rotation"
private val TRANSITION_PROPERTIES = arrayOf(PROP_ROTATION)
}
}
创建目标扩展按钮的XML文件
<?xml version="1.0" encoding="utf-8"?>
<transitionSet
xmlns:android="http://schemas.android.com/apk/res/android"
android:interpolator="@android:interpolator/fast_out_slow_in">
<transition class="com.smarttoolfactory.tutorial3_1transitions.transition.RotateX">
<targets>
<target android:targetId="@id/ivExpand" />
</targets>
</transition>
<autoTransition android:duration="200" />
</transitionSet>
My layout to be expanded or collapsed
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools">
<com.google.android.material.card.MaterialCardView
android:id="@+id/cardView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginHorizontal="4dp"
android:layout_marginVertical="2dp"
android:clickable="true"
android:focusable="true"
android:transitionName="@string/transition_card_view"
app:cardCornerRadius="0dp"
app:cardElevation="0dp"
app:cardPreventCornerOverlap="false">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="16dp"
android:paddingBottom="16dp">
<androidx.appcompat.widget.AppCompatImageView
android:id="@+id/ivAvatar"
android:layout_width="40dp"
android:layout_height="40dp"
android:layout_marginStart="16dp"
android:layout_marginTop="8dp"
android:scaleType="centerCrop"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:src="@drawable/avatar_1_raster" />
<androidx.appcompat.widget.AppCompatImageView
android:id="@+id/ivExpand"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:padding="8dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="@drawable/ic_baseline_expand_more_24" />
<TextView
android:id="@+id/tvTitle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="12dp"
android:layout_marginTop="6dp"
android:text="Some Title"
android:textSize="20sp"
android:textStyle="bold"
app:layout_constraintStart_toEndOf="@+id/ivAvatar"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/tvDate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="4dp"
android:textColor="?android:textColorSecondary"
android:textSize="12sp"
app:layout_constraintStart_toStartOf="@+id/tvTitle"
app:layout_constraintTop_toBottomOf="@id/tvTitle"
tools:text="Tuesday 7pm" />
<TextView
android:id="@+id/tvBody"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:layout_marginEnd="16dp"
android:ellipsize="end"
android:lines="1"
android:text="@string/bacon_ipsum_short"
android:textSize="16sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="@+id/ivAvatar"
app:layout_constraintTop_toBottomOf="@id/tvDate" />
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="16dp"
android:layout_marginEnd="16dp"
android:orientation="horizontal"
android:overScrollMode="never"
android:visibility="gone"
app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@id/tvBody"
tools:listitem="@layout/item_image_destination" />
</androidx.constraintlayout.widget.ConstraintLayout>
</com.google.android.material.card.MaterialCardView>
</layout>
并设置项目的可见性，以折叠或展开
private fun setUpExpandedStatus() {
if (isExpanded) {
binding.recyclerView.visibility = View.VISIBLE
binding.ivExpand.rotationX = 180f
} else {
binding.recyclerView.visibility = View.GONE
binding.ivExpand.rotationX = 0f
}
}
然后开始过渡
val transition = TransitionInflater.from(itemView.context)
.inflateTransition(R.transition.icon_expand_toggle)
TransitionManager.beginDelayedTransition(parent, transition)
isExpanded = !isExpanded
setUpExpandedStatus()
我创建了动画和过渡样本，包括gif上的那个，你可以在那里检查它们。
