Question

我正在尝试为自定义菜单创建切换动画。可以通过不同的按钮选择多个菜单。当没有菜单打开时，点击按钮应打开该菜单。如果打开了另一个菜单，则关闭打开的菜单，然后播放该动画后，应打开所选的菜单。每个关闭/打开动作都与ConstraintLayout过渡相结合。

由于无法正常工作，我创建了以下测试过程：

@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;
    }
}

运行它时，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

但是，最后一行永远不会打印；好像（在关闭动作之后再次开始打开动作之后）startMenue（）中的第一个过渡从未执行过对onTransitionEnd（）的回调。

这里是TransitionEndListener（只是接口的一个简单包装器）

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（）中放置一条打印语句来检查是否取消了第二个开始的Transition，这似乎并非如此。

你能解释为什么会这样吗？

更新

我发现了this post on TransitionManager callbacks;

从mh0c到t0 mh1c的过渡是ConstraintLayout过渡，因为约束实际上发生了变化。但是，该过渡在UI上不可见，因为过渡元素的宽度为0。（此过渡是从一个菜单点到另一个菜单点的跳转，不可见。）

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？

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；请参阅startMenue（）的代码进行更改

Answer 1

在越来越多的苦苦挣扎和审查这些帖子之后：

我发现了造成麻烦的原因：

closeMenue（）的最内层部分（最内层的回调）

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。它应该看起来像这样：

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;

这确保先完成关闭过渡，然后再开始打开过渡。

首次运行后以可运行的停止方式递归链接ConstraintLayout转换

1 个答案: