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?
平滑动画请使用Handler运行方法.....享受展开/折叠动画
class AnimUtils{
public void expand(final View v) {
int ANIMATION_DURATION=500;//in milisecond
v.measure(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
final int targtetHeight = v.getMeasuredHeight();
v.getLayoutParams().height = 0;
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)(targtetHeight * interpolatedTime);
v.requestLayout();
}
@Override
public boolean willChangeBounds() {
return true;
}
};
// 1dp/ms
a.setDuration(ANIMATION_DURATION);
// a.setDuration((int)(targtetHeight / v.getContext().getResources().getDisplayMetrics().density));
v.startAnimation(a);
}
public 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;
}
};
// 1dp/ms
a.setDuration(ANIMATION_DURATION);
// a.setDuration((int)(initialHeight / v.getContext().getResources().getDisplayMetrics().density));
v.startAnimation(a);
}
}
使用下面的代码调用:
private void setAnimationOnView(final View inactive ) {
//I am applying expand and collapse on this TextView ...You can use your view
//for expand animation
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
new AnimationUtililty().expand(inactive);
}
}, 1000);
//For collapse
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
new AnimationUtililty().collapse(inactive);
//inactive.setVisibility(View.GONE);
}
}, 8000);
}
其他解决方案是:
public void expandOrCollapse(final View v,String exp_or_colpse) {
TranslateAnimation anim = null;
if(exp_or_colpse.equals("expand"))
{
anim = new TranslateAnimation(0.0f, 0.0f, -v.getHeight(), 0.0f);
v.setVisibility(View.VISIBLE);
}
else{
anim = new TranslateAnimation(0.0f, 0.0f, 0.0f, -v.getHeight());
AnimationListener collapselistener= new AnimationListener() {
@Override
public void onAnimationStart(Animation animation) {
}
@Override
public void onAnimationRepeat(Animation animation) {
}
@Override
public void onAnimationEnd(Animation animation) {
v.setVisibility(View.GONE);
}
};
anim.setAnimationListener(collapselistener);
}
// To Collapse
//
anim.setDuration(300);
anim.setInterpolator(new AccelerateInterpolator(0.5f));
v.startAnimation(anim);
}
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);
}
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 ())
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);。
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
