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);
}
我改编了汤姆·埃斯特兹(Tom Esterez)目前接受的答案，这个答案有效，但动画起伏不定，不太流畅。我的解决方案基本上是用ValueAnimator替换动画，它可以与你选择的Interpolator相匹配，以实现各种效果，如超调、反弹、加速等。
这个解决方案非常适用于具有动态高度的视图(即使用WRAP_CONTENT)，因为它首先测量实际所需的高度，然后动画到该高度。
public static void expand(final View v) {
v.measure(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
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);
ValueAnimator va = ValueAnimator.ofInt(1, targetHeight);
va.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
public void onAnimationUpdate(ValueAnimator animation) {
v.getLayoutParams().height = (Integer) animation.getAnimatedValue();
v.requestLayout();
}
});
va.addListener(new Animator.AnimatorListener() {
@Override
public void onAnimationEnd(Animator animation) {
v.getLayoutParams().height = ViewGroup.LayoutParams.WRAP_CONTENT;
}
@Override public void onAnimationStart(Animator animation) {}
@Override public void onAnimationCancel(Animator animation) {}
@Override public void onAnimationRepeat(Animator animation) {}
});
va.setDuration(300);
va.setInterpolator(new OvershootInterpolator());
va.start();
}
public static void collapse(final View v) {
final int initialHeight = v.getMeasuredHeight();
ValueAnimator va = ValueAnimator.ofInt(initialHeight, 0);
va.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
public void onAnimationUpdate(ValueAnimator animation) {
v.getLayoutParams().height = (Integer) animation.getAnimatedValue();
v.requestLayout();
}
});
va.addListener(new Animator.AnimatorListener() {
@Override
public void onAnimationEnd(Animator animation) {
v.setVisibility(View.GONE);
}
@Override public void onAnimationStart(Animator animation) {}
@Override public void onAnimationCancel(Animator animation) {}
@Override public void onAnimationRepeat(Animator animation) {}
});
va.setDuration(300);
va.setInterpolator(new DecelerateInterpolator());
va.start();
}
然后你只需调用expand(myView);或崩溃(myView);。
这是我的解决方案。我认为这样更简单。它只是扩展了视图，但很容易扩展。
public class WidthExpandAnimation extends Animation
{
int _targetWidth;
View _view;
public WidthExpandAnimation(View view)
{
_view = view;
}
@Override
protected void applyTransformation(float interpolatedTime, Transformation t)
{
if (interpolatedTime < 1.f)
{
int newWidth = (int) (_targetWidth * interpolatedTime);
_view.layout(_view.getLeft(), _view.getTop(),
_view.getLeft() + newWidth, _view.getBottom());
}
else
_view.requestLayout();
}
@Override
public void initialize(int width, int height, int parentWidth, int parentHeight)
{
super.initialize(width, height, parentWidth, parentHeight);
_targetWidth = width;
}
@Override
public boolean willChangeBounds() {
return true;
}
}
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);
}
}));
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!
加上Tom Esterez的精彩回答和Erik B的精彩更新，我想我应该发布我自己的观点，将扩展和收缩方法压缩为一个。通过这种方式，你可以有这样一个动作……
button.setOnClickListener(v -> expandCollapse(view));
．.． 它调用下面的方法，并让它在每次onClick()之后弄清楚要做什么…
public static void expandCollapse(View view) {
boolean expand = view.getVisibility() == View.GONE;
Interpolator easeInOutQuart = PathInterpolatorCompat.create(0.77f, 0f, 0.175f, 1f);
view.measure(
View.MeasureSpec.makeMeasureSpec(((View) view.getParent()).getWidth(), View.MeasureSpec.EXACTLY),
View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED)
);
int height = view.getMeasuredHeight();
int duration = (int) (height/view.getContext().getResources().getDisplayMetrics().density);
Animation animation = new Animation() {
@Override protected void applyTransformation(float interpolatedTime, Transformation t) {
if (expand) {
view.getLayoutParams().height = 1;
view.setVisibility(View.VISIBLE);
if (interpolatedTime == 1) {
view.getLayoutParams().height = ViewGroup.LayoutParams.WRAP_CONTENT;
} else {
view.getLayoutParams().height = (int) (height * interpolatedTime);
}
view.requestLayout();
} else {
if (interpolatedTime == 1) {
view.setVisibility(View.GONE);
} else {
view.getLayoutParams().height = height - (int) (height * interpolatedTime);
view.requestLayout();
}
}
}
@Override public boolean willChangeBounds() {
return true;
}
};
animation.setInterpolator(easeInOutQuart);
animation.setDuration(duration);
view.startAnimation(animation);
}
