我正在尝试在Honeycomb的新LayoutTransition类.在将视图添加到ViewGroup中时,我已经设置了将视图滑动到的位置的动画.我注意到,当首先渲染视图和LayoutTransition.APPEARING动画开始之间时,稍微延迟(约20ms).换句话说,在视图出现在屏幕上后,它挂在空中一会儿,然后开始动画到位.即使在ApiDemos示例项目中也可以注意到这一点.在布局动画示例中,在ViewGroup的APPEARING动画开始之前总是有延迟.我甚至尝试将其他LayoutTransition动画设置为null,或者最终给他们很短的持续时间,但是仍然会延迟APPEARING动画.这是我的代码：

public class DebugExampleFour extends Activity {

private int numButtons = 1;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.debug_example_four);

final ViewGroup frame = (ViewGroup) findViewById(R.id.frame_container);

LayoutTransition transitioner = new LayoutTransition();

Animator appearingAnimation = ObjectAnimator.ofFloat(null, "translationX", 600, 0);

appearingAnimation.setDuration(45);

appearingAnimation.setStartDelay(0);

appearingAnimation.setInterpolator(new DecelerateInterpolator());

appearingAnimation.addListener(new AnimatorListenerAdapter() {

public void onAnimationEnd(Animator anim) {

View view = (View) ((ObjectAnimator) anim).getTarget();

view.setTranslationX(0f);

}

});

transitioner.setAnimator(LayoutTransition.APPEARING, appearingAnimation);

Animator dummyAnimation = ObjectAnimator.ofInt(0, 1);

dummyAnimation.setDuration(1);

dummyAnimation.setStartDelay(0);

transitioner.setAnimator(LayoutTransition.CHANGE_APPEARING, dummyAnimation);

transitioner.setAnimator(LayoutTransition.CHANGE_DISAPPEARING, dummyAnimation);

transitioner.setAnimator(LayoutTransition.DISAPPEARING, dummyAnimation);

frame.setLayoutTransition(transitioner);

Button addButton = (Button) findViewById(R.id.addNewButton);

addButton.setOnClickListener(new View.OnClickListener() {

public void onClick(View v) {

Button newButton = new Button(DebugExampleFour.this);

newButton.setText("Click To Remove " + (numButtons++));

newButton.setOnClickListener(new View.OnClickListener() {

public void onClick(View v) {

frame.removeView(v);

}

});

frame.addView(newButton, new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));

}

});

}

}

这里是与该示例一起的布局文件：

android:layout_width="match_parent" android:layout_height="match_parent"

android:orientation="vertical">

android:layout_height="wrap_content" android:text="Add Button"

android:id="@+id/addNewButton" />

android:layout_width="match_parent" android:layout_height="match_parent"

android:id="@+id/frame_container" android:animateLayoutChanges="true" />

如何在APPEARING动画之前消除延迟？