在Android中动画移动一个View的位置,采用Scroller类实现
今天说最近自己遇到的一个问题,就是要用动画效果来移动一个VIew的位置。
这个具体的情况是,需要做一个SlidingMenu的app,之前找了一个开源的,但不知道为什么,用起来app的运行效率很低,会有卡顿的现象。无奈只要自己写了。
SlidingMenu核心的就是可以滑动拉开左侧和右侧的菜单。刚开始考虑用TranslationAnimation来做。不过TranslationAnimation并不是真的移动一个View的坐标,在网上找了找,需要在Animation结束的时候,重新去layout下View的坐标,经过测试,这个方式可以达到预期效果。代码如下:
final int xOffset = leftFrameLayout.getWidth();
TranslateAnimation translateAnimation = new TranslateAnimation(0, xOffset, 0, 0); translateAnimation.setDuration(200);
translateAnimation.setAnimationListener(new Animation.AnimationListener() {
@Override
public void onAnimationStart(Animation animation) {
//To change body of implemented methods use File | Settings | File Templates.
} @Override
public void onAnimationEnd(Animation animation) {
int left = xOffset;
int top = centerFrameLayout.getTop();
int width = centerFrameLayout.getWidth();
int height = centerFrameLayout.getHeight();
centerFrameLayout.clearAnimation();
centerFrameLayout.layout(left, top, left + width, top + height); leftFrameLayout.bringToFront();
} @Override
public void onAnimationRepeat(Animation animation) {
//To change body of implemented methods use File | Settings | File Templates.
}
});
centerFrameLayout.startAnimation(translateAnimation);
貌似没什么问题了,不过我的界面中,当显示SldingMenu的侧边栏的时候,里面有个输入框,点击输入框弹出键盘的时候,会导致界面重新layout,这时候中间被移动的view,就又给自动移动回来了,看来用
centerFrameLayout.layout
无法解决键盘弹出时候的重绘。
这时考虑到使用Scroller类来进行动画移动。也是参考了网上的例子,将我中间部分的FrameLayout搞成一个自定义类,代码如下:
public class ScrollableFrameLayout extends FrameLayout {
private Scroller scroller; public ScrollableFrameLayout(Context context) {
super(context);
init();
} public ScrollableFrameLayout(Context context, AttributeSet attrs) {
super(context, attrs);
init();
} public ScrollableFrameLayout(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
} private void init(){
scroller = new Scroller(getContext());
} @Override
public void scrollTo(int x, int y) {
super.scrollTo(x, y);
postInvalidate();
} @Override
public void computeScroll() {
if (!scroller.isFinished()) {
if (scroller.computeScrollOffset()) {
int oldX = getScrollX();
int oldY = getScrollY();
int x = scroller.getCurrX();
int y = scroller.getCurrY();
if (oldX != x || oldY != y) {
scrollTo(x, y);
}
// Keep on drawing until the animation has finished.
invalidate();
} else {
clearChildrenCache();
}
} else {
clearChildrenCache();
}
} public void smoothScrollTo(int dx, int duration) { int oldScrollX = getScrollX();
scroller.startScroll(oldScrollX, getScrollY(), dx, getScrollY(), duration);
invalidate();
} private void enableChildrenCache() {
final int count = getChildCount();
for (int i = 0; i < count; i++) {
final View layout = (View) getChildAt(i);
layout.setDrawingCacheEnabled(true);
}
} private void clearChildrenCache() {
final int count = getChildCount();
for (int i = 0; i < count; i++) {
final View layout = (View) getChildAt(i);
layout.setDrawingCacheEnabled(false);
}
} }
然后在需要移动这个类的地方调用:
int xOffset = rightFrameLayout.getWidth(); centerFrameLayout.bringToFront(); centerFrameLayout.smoothScrollTo(-xOffset, SCROLL_DURATION); handler.postDelayed(new Runnable() {
@Override
public void run() {
rightFrameLayout.setVisibility(View.INVISIBLE);
}
}, SCROLL_DURATION);
问题完美解决