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);
}
}
这是非常简单的droidQuery。首先，考虑这样的布局:
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical" >
<LinearLayout
android:id="@+id/v1"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="View 1" />
</LinearLayout>
<LinearLayout
android:id="@+id/v2"
android:layout_width="wrap_content"
android:layout_height="0dp" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="View 2" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="View 3" />
</LinearLayout>
</LinearLayout>
我们可以使用下面的代码将高度动画到所需的值-比如100dp:
//convert 100dp to pixel value
int height = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 100, getResources().getDisplayMetrics());
然后使用droidQuery进行动画。最简单的方法是:
$.animate("{ height: " + height + "}", new AnimationOptions());
为了让动画更吸引人，可以考虑添加一个easing:
$.animate("{ height: " + height + "}", new AnimationOptions().easing($.Easing.BOUNCE));
你也可以使用duration()方法改变AnimationOptions上的持续时间，或者处理动画结束时发生的事情。对于一个复杂的例子，试试:
$.animate("{ height: " + height + "}", new AnimationOptions().easing($.Easing.BOUNCE)
.duration(1000)
.complete(new Function() {
@Override
public void invoke($ d, Object... args) {
$.toast(context, "finished", Toast.LENGTH_SHORT);
}
}));
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;
}
}
@Tom Esterez的回答，但更新为正确使用view.measure()每个Android getMeasuredHeight返回错误的值!
// http://easings.net/
Interpolator easeInOutQuart = PathInterpolatorCompat.create(0.77f, 0f, 0.175f, 1f);
public static Animation expand(final View view) {
int matchParentMeasureSpec = View.MeasureSpec.makeMeasureSpec(((View) view.getParent()).getWidth(), View.MeasureSpec.EXACTLY);
int wrapContentMeasureSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
view.measure(matchParentMeasureSpec, wrapContentMeasureSpec);
final int targetHeight = view.getMeasuredHeight();
// Older versions of android (pre API 21) cancel animations for views with a height of 0 so use 1 instead.
view.getLayoutParams().height = 1;
view.setVisibility(View.VISIBLE);
Animation animation = new Animation() {
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
view.getLayoutParams().height = interpolatedTime == 1
? ViewGroup.LayoutParams.WRAP_CONTENT
: (int) (targetHeight * interpolatedTime);
view.requestLayout();
}
@Override
public boolean willChangeBounds() {
return true;
}
};
animation.setInterpolator(easeInOutQuart);
animation.setDuration(computeDurationFromHeight(view));
view.startAnimation(animation);
return animation;
}
public static Animation collapse(final View view) {
final int initialHeight = view.getMeasuredHeight();
Animation a = new Animation() {
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
if (interpolatedTime == 1) {
view.setVisibility(View.GONE);
} else {
view.getLayoutParams().height = initialHeight - (int) (initialHeight * interpolatedTime);
view.requestLayout();
}
}
@Override
public boolean willChangeBounds() {
return true;
}
};
a.setInterpolator(easeInOutQuart);
int durationMillis = computeDurationFromHeight(view);
a.setDuration(durationMillis);
view.startAnimation(a);
return a;
}
private static int computeDurationFromHeight(View view) {
// 1dp/ms * multiplier
return (int) (view.getMeasuredHeight() / view.getContext().getResources().getDisplayMetrics().density);
}
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)
}
}
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();
}
