[英]How to animate the height of a View?
我有一个我创建的方法,在我的项目中调用,我做了因为我有一个Crouton(吐司)告诉用户激活那个帐户,或者当没有有效的互联网连接时它也会提醒他们...我不希望它干扰我的视图顶部,因为那里的用户操作非常重要。 我使用RelativeLayout
首先,这段代码无论如何都不起作用,但是当我修复它时,我意识到我在底部之间切换不同的活动现在已经消失,因为它已经滑落了,我想我可以调整大小。
任何人都可以指出我正确的方向为两个事情,一个调整高度而不是滑动整个视图,两个,帮助我修复崩溃我得到,这发生在setLayoutParam
我称之为teknoloGenie.slideViewDown("100", findViewById(R.id.RootView));
public void slideViewDown(final String distX, final View view) {
final TranslateAnimation slideDown = new TranslateAnimation(0, 0, 0, Float.parseFloat(distX));
slideDown.setDuration(500);
slideDown.setFillEnabled(true);
slideDown.setAnimationListener(new Animation.AnimationListener() {
@Override
public void onAnimationStart(Animation animation) {
}
@Override
public void onAnimationRepeat(Animation animation) {
}
@Override public void onAnimationEnd(Animation animation) {
RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams)view.getLayoutParams();
params.addRule(RelativeLayout.CENTER_HORIZONTAL, -1);
params.setMargins(0, view.getTop()+Integer.parseInt(distX), 0, 0);
view.setLayoutParams(params);
view.requestLayout();
}
});
view.startAnimation(slideDown);
}
如果要为视图的高度设置动画,则需要编写自己的自定义动画并修改动画视图的LayoutParams
。 在此示例中,动画为动画视图的高度设置动画。
这是它的样子:
public class ResizeAnimation extends Animation {
private int startHeight;
private int deltaHeight; // distance between start and end height
private View view;
/**
* constructor, do not forget to use the setParams(int, int) method before
* starting the animation
* @param v
*/
public ResizeAnimation (View v) {
this.view = v;
}
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
view.getLayoutParams().height = (int) (startHeight + deltaHeight * interpolatedTime);
view.requestLayout();
}
/**
* set the starting and ending height for the resize animation
* starting height is usually the views current height, the end height is the height
* we want to reach after the animation is completed
* @param start height in pixels
* @param end height in pixels
*/
public void setParams(int start, int end) {
this.startHeight = start;
deltaHeight = end - startHeight;
}
@Override
public boolean willChangeBounds() {
return true;
}
}
在代码中, 创建一个新动画并将其应用于要设置动画的RelativeLayout :
View v = findViewById(R.id.youranimatedview);
// getting the layoutparams might differ in your application, it depends on the parent layout
RelativeLayout.LayoutParams lp = (RelativeLayout.LayoutParams) v.getLayoutParams();
ResizeAnimation a = new ResizeAnimation(v);
a.setDuration(500);
// set the starting height (the current height) and the new height that the view should have after the animation
a.setParams(lp.height, newHeight);
v.startAnimation(a);
对于LayoutParams问题:
我的猜测是你得到一个ClassCastException,因为你没有使用正确的LayoutParams类。 如果您的动画视图包含在RelativeLayout中,则只能将RelativeLayout.LayoutParams
设置为它。 如果您的视图包含在LinearLayout中,则只能为View设置LinearLayout.LayoutParams
。
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