片段交易动画完成后执行动作

Question

我想在动画完成后设置按钮可见性。

这就是所谓的动画：

android.support.v4.app.FragmentTransaction fAnimation = this.getActivity().getSupportFragmentManager().beginTransaction();
fAnimation.setCustomAnimations(android.R.anim.slide_in_left, R.anim.pull_out_to_left);
if (this.isVisible()) {
    fAnimation.hide(this);
    fAnimation.commit();
}

// code that will be executed when the fragment is gone (after the animation is over)

有什么方法可以附加一个监听器以知道我的片段何时消失？

Answer 1

@nmw 在他的回答中实现的动画器是在 API 级别 11 中添加的，并且不能与 Android 支持库实现的片段一起使用。

为了监听 Fragment 动画事件，我扩展了支持库的 Fragment 类并覆盖了 onCreateAnimation，将自定义 AnimationListener 附加到返回的 Animation 对象：

public class MyFragment extends android.support.v4.app.Fragment {

    private static final String TAG = "MyFragment";

    @Override
    public Animation onCreateAnimation(int transit, boolean enter, int nextAnim) {

        Animation anim = AnimationUtils.loadAnimation(getActivity(), nextAnim);

        anim.setAnimationListener(new AnimationListener() {

            @Override
            public void onAnimationStart(Animation animation) {
                Log.d(TAG, "Animation started.");
                // additional functionality 
            }

            @Override
            public void onAnimationRepeat(Animation animation) {
                Log.d(TAG, "Animation repeating.");
                // additional functionality
            }

            @Override
            public void onAnimationEnd(Animation animation) {
                Log.d(TAG, "Animation ended.");
                // additional functionality
            }
        });

        return anim;
    }
}

Answer 2

您需要继承 Fragment 并覆盖 onCreateAnimator，然后您可以从 XML 加载这些动画并将侦听器附加到它们。

例如

public class MyFragment extends Fragment
{
    @Override
    public Animator onCreateAnimator(int transit, boolean enter, int nextAnim)
    {
        final int animatorId = (enter) ? R.anim.in_anim : R.anim.out_anim;
        final Animator anim = AnimatorInflater.loadAnimator(getActivity(), animatorId);
        anim.addListener(new AnimatorListenerAdapter()
        {
            @Override
            public void onAnimationStart(Animator animation)
            {
                ...
            }

            @Override
            public void onAnimationEnd(Animator animation)
            {
               ...
            }
        });

        return anim;
   }    

Answer 3

结合上面的答案是我成功使用支持库片段的示例。

只需扩展 MenuFragment 并将侦听器设置为获取之后执行的回调。

public class MenuFragment extends Fragment {

private WeakReference<OnMenuClosedListener> onMenuClosedListener;

@Override
public Animation onCreateAnimation(int transit, boolean enter, int nextAnim) {
    Animation anim = null;
    if (enter) {
        anim = AnimationUtils.loadAnimation(getActivity(), R.anim.anim_slide_in_top);
    } else {
        anim = AnimationUtils.loadAnimation(getActivity(), R.anim.anim_menu_slide_out_top);
        anim.setAnimationListener(new AnimationListener() {
            @Override public void onAnimationStart(Animation animation) {
            }
            @Override public void onAnimationRepeat(Animation animation) {
            }
            @Override public void onAnimationEnd(Animation animation) {
                onMenuClosed();
            }
        });
    }

    // NOTE: the animation must be added to an animation set in order for the listener
    // to work on the exit animation
    AnimationSet animSet = new AnimationSet(true);
    animSet.addAnimation(anim);

    return animSet;
}

private void onMenuClosed() {
    if (this.onMenuClosedListener != null) {
        OnMenuClosedListener listener = this.onMenuClosedListener.get();
        if (listener != null) {
            listener.onMenuClosed();
        }
    }
}

public void setOnMenuClosedListener(OnMenuClosedListener listener) {
    this.onMenuClosedListener = new WeakReference<MenuFragment.OnMenuClosedListener>(listener);
}

/**
 * Callback for when the menu is closed.
 */
public static interface OnMenuClosedListener {

    public abstract void onMenuClosed();

}

}

Answer 4

添加到 API 26（和支持库）中，您可以使用

 FragmentTransaction runOnCommit (Runnable runnable);

例如：

FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.setCustomAnimations(R.anim.enter_from_right, R.anim.exit_from_left);
ft.show(YourFragment);
ft.commit();
ft.runOnCommit(() -> Your_Action_Here);

Answer 5

我必须在 Xamarin 中执行此操作。我的情况是片段动画结束后我需要回调。以下是我如何让它在没有任何闪烁的情况下工作（这是 C#/Xamarin）：

    public override Animation OnCreateAnimation(int transit, bool enter, int nextAnim)
    {
        Animation anim = base.OnCreateAnimation(transit, enter, nextAnim);

        if (anim == null && nextAnim != 0) {
            anim = AnimationUtils.LoadAnimation(Activity, nextAnim);
        }

        anim.SetAnimationListener(this);
        return anim;
    }

    public void OnAnimationEnd(Animation animation)
    {
    }

    public void OnAnimationRepeat(Animation animation)
    {
    }

    public void OnAnimationStart(Animation animation)
    {
    }

注意：

• 父片段必须实现Animation.IAnimationListener
• 您必须返回一个 AnimationSet 否则 FragmentManager 将覆盖您的侦听器并且不会触发回调。