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);
}
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;
}
}
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);
}
我试图做一个我认为非常相似的动画，并找到了一个优雅的解决方案。这段代码假设你总是从0->h或h->0 (h是最大高度)。三个构造函数参数是view =要动画的视图(在我的例子中是webview)， targetHeight =视图的最大高度，以及down =一个布尔值，用于指定方向(true =展开，false =折叠)。
public class DropDownAnim extends Animation {
private final int targetHeight;
private final View view;
private final boolean down;
public DropDownAnim(View view, int targetHeight, boolean down) {
this.view = view;
this.targetHeight = targetHeight;
this.down = down;
}
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
int newHeight;
if (down) {
newHeight = (int) (targetHeight * interpolatedTime);
} else {
newHeight = (int) (targetHeight * (1 - interpolatedTime));
}
view.getLayoutParams().height = newHeight;
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;
}
}
好吧，我刚刚发现了一个非常丑陋的解决方案:
public static Animation expand(final View v, Runnable onEnd) {
try {
Method m = v.getClass().getDeclaredMethod("onMeasure", int.class, int.class);
m.setAccessible(true);
m.invoke(
v,
MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),
MeasureSpec.makeMeasureSpec(((View)v.getParent()).getMeasuredHeight(), MeasureSpec.AT_MOST)
);
} catch (Exception e){
Log.e("test", "", e);
}
final int initialHeight = v.getMeasuredHeight();
Log.d("test", "initialHeight="+initialHeight);
v.getLayoutParams().height = 0;
v.setVisibility(View.VISIBLE);
Animation a = new Animation()
{
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
final int newHeight = (int)(initialHeight * interpolatedTime);
v.getLayoutParams().height = newHeight;
v.requestLayout();
}
@Override
public boolean willChangeBounds() {
return true;
}
};
a.setDuration(5000);
v.startAnimation(a);
return a;
}
请随意提出一个更好的解决方案!
