递归链接 ConstraintLayout 转换与 Runnable 在第一个运行后停止

Question

我正在尝试为自定义菜单创建切换动画。有多个菜单，可以通过不同的按钮进行选择。当没有菜单打开时，点击按钮应该打开该菜单。如果另一个菜单打开，则打开的菜单将关闭，并且在该动画之后，应打开所选的菜单。每个 closing/opening 动作都与 ConstraintLayout 转换相结合。

由于无法正常工作，我创建了以下测试程序：

@Override
protected void onCreate(Bundle savedInstanceState) {
    ...
    ConstraintLayout layout_main;
    ConstraintSet l_mh0c = new ConstraintSet();
    ConstraintSet l_mh1o = new ConstraintSet();
    ConstraintSet l_mh1c = new ConstraintSet();

    Button btn;
    btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            toggleOne();
        }
    });
    layout_main = (ConstraintLayout) findViewById(R.id.constraintMain);
    l_mh1o.clone(this, R.layout.main_menue_header1_open);
    l_mh1c.clone(this, R.layout.main_menue_header1_closed);
    l_mh0c.clone(this, R.layout.activity_main);
    ...
}

int openedMenue = -1;
long animationTime = 1000;
private void toggleOne() {
    TransitionManager.endTransitions(layout_main); //<- makes no difference when commented
    if(openedMenue==1) {              
        System.out.println("sync closing");
        Runnable r = () -> toggleOne();
        closeMenue(1, animationTime, r);
    } else {
        System.out.println("sync opening");
        startMenue(1, animationTime);
    }
}

public void startMenue(Integer index, final Long maxtime) {
    Transition t;
    switch (index) {
        case 1:
            t = new ChangeBounds();
            t.setDuration(0).addListener(new TransitionEndListener() {
                @Override
                public void onTransitionEnd(Transition transition) {
                    Transition t = new ChangeBounds();
                    t.setDuration(maxtime / 2).addListener(new TransitionEndListener() {
                        @Override
                        public void onTransitionEnd(Transition transition) {
                            Transition t = new ChangeBounds();
                            t.setDuration(maxtime / 2);
                            TransitionManager.beginDelayedTransition(layout_main, t);
                            l_mh0o.applyTo(layout_main);
                            openedMenue = 1;
                            System.out.println("sync start finished");
                        }
                    });
                    TransitionManager.beginDelayedTransition(layout_main, t);
                    l_mh1o.applyTo(layout_main);

                }
            });
            TransitionManager.beginDelayedTransition(layout_main, t);
            l_mh1c.applyTo(layout_main);
            // the following does not provoke any changes
            Scene s = new Scene(layout_main); 
            TransitionManager.go(s);
            break;
    }
}

private void closeMenue(int index, final long maxtime, Runnable callback) {
    System.out.println("sync closing menue " + openedMenue);
    Transition t;
    switch (index) {
        case 1:
            t = new ChangeBounds();
            t.setDuration(maxtime/2).addListener(new TransitionEndListener() {
                @Override
                public void onTransitionEnd(Transition transition) {
                    Transition t = new ChangeBounds();
                    t.setDuration(maxtime/2).addListener(new TransitionEndListener() {
                        @Override
                        public void onTransitionEnd(Transition transition) {
                            Transition t = new ChangeBounds();
                            t.setDuration(0);
                            TransitionManager.beginDelayedTransition(layout_main, t);
                            l_mh0c.applyTo(layout_main);
                            openedMenue = -1;
                            try {
                                callback.run();
                            } catch (Exception e) { e.printStackTrace(); }
                        }
                    });
                    TransitionManager.beginDelayedTransition(layout_main, t);
                    l_mh1c.applyTo(layout_main);
                    openedMenue = 1;
                }
            });
            TransitionManager.beginDelayedTransition(layout_main, t);
            l_mh1o.applyTo(layout_main);
            break;
    }
}

当我运行它时，我得到以下输出：

[Button Click]
sync opening
sync start finished
[Button Click]
sync closing
sync closing menue 1
sync opening
sync start finished // problem

然而，最后一行从未被打印；似乎（在关闭动作再次开始打开动作之后）startMenue() 中的第一个转换从未对 onTransitionEnd() 进行回调。

这里是 TransitionEndListener（只是接口的简单包装）

public abstract class TransitionEndListener implements Transition.TransitionListener {

    @Override
    public final void onTransitionStart(Transition transition) {}

    @Override
    public final void onTransitionCancel(Transition transition) {}

    @Override
    public final void onTransitionPause(Transition transition) {}

    @Override
    public final void onTransitionResume(Transition transition) {}
}

我已经通过在 onTransitionCancel() 中放置打印语句来检查是否取消了第二个开始转换，但似乎并非如此。

你能解释一下为什么会这样吗？

更新

我找到了 this post on TransitionManager callbacks;

从 mh0c t0 mh1c 的过渡是 ConstraintLayout 过渡，因为约束实际上发生了变化；但是，过渡在 UI 上不可见，因为过渡中元素的宽度为 0。（此过渡是从一个菜单点跳转到不应该可见的另一个菜单点。）

这可能是 Transition 不执行回调的原因吗？

如果是的话；我该如何解决这个问题？

更新 2 我正在阅读 the documentation，可能已经找到了使用 TransitionManager.go(scene, transition) 的解决方案。

--> 不幸的是这没有用；查看 startMenue() 的代码以进行更改

Answer 1

经过越来越多的努力和审查这些帖子：

TransitionListener callbacks not called when there is nothing to change

我已经找出问题的原因：

在closeMenue()的最里面（最里面的回调）

Transition t = new ChangeBounds();
t.setDuration(0);
TransitionManager.beginDelayedTransition(layout_main, t);
l_mh0c.applyTo(layout_main);
openedMenue = -1;
try {
     callback.run();
} catch (Exception e) { e.printStackTrace(); }

命令顺序略有错误。它应该是这样的：

Transition t = new ChangeBounds();
t.setDuration(0).addListener(new TransitionEndListener() {
    @Override
    public void onTransitionEnd(Transition transition) {
        try {
            callback.run();
        } catch (Exception e) { e.prtinStackTrace(); }
    }
});
TransitionManager.beginDelayedTransition(layout_main, t);
l_mh0c.applyTo(layout_main);
openedMenue = -1;

这确保首先完成结束过渡，然后开始开放过渡。

递归链接 ConstraintLayout 转换与 Runnable 在第一个运行后停止

Recursively Chaining ConstraintLayout Transitions with Runnable stops after first run

android

runnable

android-transitions

android-constraintlayout

递归链接 ConstraintLayout 转换与 Runnable 在第一个 运行 后停止

Recursively Chaining ConstraintLayout Transitions with Runnable stops after first run

android

runnable

android-transitions

android-constraintlayout

递归链接 ConstraintLayout 转换与 Runnable 在第一个运行后停止