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?
根据@Tom Esterez和@Seth Nelson的解决方案，我对它们进行了简化。与原始解决方案一样，它不依赖于开发人员选项(动画设置)。
private void resizeWithAnimation(final View view, int duration, final int targetHeight) {
final int initialHeight = view.getMeasuredHeight();
final int distance = targetHeight - initialHeight;
view.setVisibility(View.VISIBLE);
Animation a = new Animation() {
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
if (interpolatedTime == 1 && targetHeight == 0) {
view.setVisibility(View.GONE);
}
view.getLayoutParams().height = (int) (initialHeight + distance * interpolatedTime);
view.requestLayout();
}
@Override
public boolean willChangeBounds() {
return true;
}
};
a.setDuration(duration);
view.startAnimation(a);
}
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);
}
}
这是一个片段，我用来调整一个视图(线性布局)的宽度与动画。
代码应该根据目标大小进行扩展或收缩。如果你想要一个fill_parent宽度，你必须在将标志设置为true时将父类. getmeasuredwidth作为目标宽度。
希望它能帮助到你们中的一些人。
public class WidthResizeAnimation extends Animation {
int targetWidth;
int originaltWidth;
View view;
boolean expand;
int newWidth = 0;
boolean fillParent;
public WidthResizeAnimation(View view, int targetWidth, boolean fillParent) {
this.view = view;
this.originaltWidth = this.view.getMeasuredWidth();
this.targetWidth = targetWidth;
newWidth = originaltWidth;
if (originaltWidth > targetWidth) {
expand = false;
} else {
expand = true;
}
this.fillParent = fillParent;
}
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
if (expand && newWidth < targetWidth) {
newWidth = (int) (newWidth + (targetWidth - newWidth) * interpolatedTime);
}
if (!expand && newWidth > targetWidth) {
newWidth = (int) (newWidth - (newWidth - targetWidth) * interpolatedTime);
}
if (fillParent && interpolatedTime == 1.0) {
view.getLayoutParams().width = -1;
} else {
view.getLayoutParams().width = newWidth;
}
view.requestLayout();
}
@Override
public void initialize(int width, int height, int parentWidth, int parentHeight) {
super.initialize(width, height, parentWidth, parentHeight);
}
@Override
public boolean willChangeBounds() {
return true;
}
}
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。
