ActivityTaskView

新版使用方法

Github地址：https://github.com/rome753/ActivityTaskView

1. 安装ActivityTaskView release app，启动并给予悬浮窗权限
   https://github.com/rome753/ActivityTaskView/releases
   或者从 Google Play下载安装。

2. 在你开发的App中加入如下类https://github.com/rome753/ActivityTaskView/blob/master/app/src/main/java/cc/rome753/demo/ActivityTaskHelper.java

3. 在你开发的App的Application的onCreate()中加入代码

ActivityManager am = (ActivityManager)getSystemService(Context.ACTIVITY_SERVICE);
List<RunningTaskInfo> runningTaskInfoList =  am.getRunningTasks(10);
for (RunningTaskInfo runningTaskInfo : runningTaskInfoList) {
    log("id: " + runningTaskInfo.id);
    log("description: " + runningTaskInfo.description);
    log("number of activities: " + runningTaskInfo.numActivities);
    log("topActivity: " + runningTaskInfo.topActivity);
    log("baseActivity: " + runningTaskInfo.baseActivity.toString());
}

该方法只能获取到任务栈的栈顶和栈底的活动，操作起来也麻烦。

总之，目前还没有一种方法能直观地观察Activity任务栈和Activity中的Fragment，像下图这样：

原理

Android4.0以后Application支持ActivityLifecycleCallbacks和FragmentLifecycleCallbacks的生命周期回调。

ActivityLifecycleCallbacks

private class FragmentLifecycleImpl extends FragmentManager.FragmentLifecycleCallbacks{

        @Override
        public void onFragmentPreAttached(FragmentManager fm, Fragment f, Context context) {
        }

        @Override
        public void onFragmentAttached(FragmentManager fm, Fragment f, Context context) {
        }

        @Override
        public void onFragmentCreated(FragmentManager fm, Fragment f, Bundle savedInstanceState) {
        }

        @Override
        public void onFragmentActivityCreated(FragmentManager fm, Fragment f, Bundle savedInstanceState) {
        }

        @Override
        public void onFragmentViewCreated(FragmentManager fm, Fragment f, View v, Bundle savedInstanceState) {
        }

        @Override
        public void onFragmentStarted(FragmentManager fm, Fragment f) {
            handleFragment(f);
        }

        @Override
        public void onFragmentResumed(FragmentManager fm, Fragment f) {
        }

        @Override
        public void onFragmentPaused(FragmentManager fm, Fragment f) {
        }

        @Override
        public void onFragmentStopped(FragmentManager fm, Fragment f) {
        }

        @Override
        public void onFragmentSaveInstanceState(FragmentManager fm, Fragment f, Bundle outState) {
        }

        @Override
        public void onFragmentViewDestroyed(FragmentManager fm, Fragment f) {
        }

        @Override
        public void onFragmentDestroyed(FragmentManager fm, Fragment f) {
        }

        @Override
        public void onFragmentDetached(FragmentManager fm, Fragment f) {
        }
    }

同理，在Activity启动时可以给它注册FragmentLifecycleCallbacks来监听Activity中Fragment的变化。不同于Activity在Task中是线性的数据结构，Fragment在Activity中是树状的：一个Activity中可以有多个Fragment，每个Fragment又可以有自己的子Fragment。因此本地需要维护一个树FTree。

FTree.java

WindowManager windowManager = (WindowManager)app.getSystemService(Context.WINDOW_SERVICE);
WindowManager.LayoutParams params = new WindowManager.LayoutParams();
params.type = WindowManager.LayoutParams.TYPE_PHONE;
params.format = PixelFormat.RGBA_8888;
params.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE;
params.width = WindowManager.LayoutParams.WRAP_CONTENT;
params.height = WindowManager.LayoutParams.WRAP_CONTENT;
params.gravity = Gravity.START | Gravity.TOP;
params.x = 0;
params.y = app.getResources().getDisplayMetrics().heightPixels;
windowManager.addView(activityTaskView, params);

添加悬浮窗用这个方法就可以了，加上悬浮窗权限。

    float mInnerX;
    float mInnerY;
    long downTime;

    @Override
        public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                downTime = System.currentTimeMillis();
                mInnerX = event.getX();
                mInnerY = event.getY();
                postDelayed(this, 300);
                break;
            case MotionEvent.ACTION_MOVE:
                float x = event.getRawX();
                float y = event.getRawY();
                WindowManager.LayoutParams params = (WindowManager.LayoutParams) getLayoutParams();
                params.x = (int) (x - mInnerX);
                params.y = (int) (y - mInnerY - mStatusHeight);
                updateLayout(params);

                if(Math.abs(event.getX() - mInnerX) > 20
                        || Math.abs(event.getY() - mInnerY) > 20) {
                    removeCallbacks(this);
                }
                break;
            case MotionEvent.ACTION_UP:
                removeCallbacks(this);
                if(System.currentTimeMillis() - downTime < 100
                        && Math.abs(event.getX() - mInnerX) < 20
                        && Math.abs(event.getY() - mInnerY) < 20) {
                    doClick();
                }
                moveToBorder();
                break;

        }
        return true;
    }

    private void doClick() {
        boolean visible = mTaskView.getVisibility() == VISIBLE;
        mTaskView.setVisibility(visible ? GONE : VISIBLE);
        mTinyView.setVisibility(!visible ? GONE : VISIBLE);
    }

    private void doLongClick() {
        Intent intent = new Intent(getContext().getApplicationContext(), MainActivity.class);
        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        getContext().getApplicationContext().startActivity(intent);
    }

    private void updateLayout(WindowManager.LayoutParams params){
        WindowManager windowManager = (WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE);
        if(windowManager != null) {
            windowManager.updateViewLayout(this, params);
        }
    }

    private void moveToBorder() {
        WindowManager.LayoutParams p = (WindowManager.LayoutParams) getLayoutParams();
        Log.d("chao", "x " + p.x + " " + ((mScreenWidth - getWidth()) / 2));

        if(p.x <= (mScreenWidth - getWidth()) / 2) { // move left
            p.x = 0;
        } else { // move right
            p.x = mScreenWidth;
        }
        updateLayout(p);
    }

ActivityTaskView的视图

视图分为三层：
最外层是ActivityTask活动栈，它是从Activity中取得的。不同的App自然是不同的栈（包名不同），一个App也可以有多个栈（包名相同，hashcode不同）；
中间层是活动栈中的Activity，在每个栈中是线性排列的；
最内层是Acitivity中的Fragment，一个Activity中可以有多个Fragment，一个Fragment中也可以有多个子Fragment，因此用一个简单的树来显示。

正常情况下，能准确地表示当前APP的活动栈和Fragment。除了APP被异常杀死，此时不会有生命周期回调，悬浮窗也不会刷新。

延时消息队列

很多时候Activity的生命周期转换太快，比如从onStart到onPause，或从一个Activity的onPause到另一个Activity的onResume，如果实时把这些变化反映到ActivityTaskView上，就很难看清中间的变化过程。因此在新版本中添加了一个延时消息队列，思路如下：
生命周期产生时，先将对应的信息添加到一个Queue队列中，用一个Handler从队列中取消息，如果本次取消息距上一次取消息的间隔时间小于规定DELAY，那么就等待一段时间重新取。满足时间间隔才把生命周期反映到界面上。

public class ViewPool extends Observable {

    LinkedList<ATextView> pool = new LinkedList<>();
    HashMap<String,FragmentTaskView> map = new HashMap<>();

    private static ViewPool factory = new ViewPool();
    public static ViewPool get() {
        return factory;
    }

    public void recycle(ViewGroup viewGroup) {
        if(viewGroup != null) {
            for(int i = 0; i < viewGroup.getChildCount(); i++) {
                View view = viewGroup.getChildAt(i);
                if(view instanceof ATextView) {
                    AUtils.removeParent(view);
                    view.setTag(null);
                    pool.add((ATextView) view);
                } else if(view instanceof FragmentTaskView) {
                    // don't recycle
                } else if(view instanceof ViewGroup) {
                    recycle((ViewGroup) view);
                }
            }
        }
    }

    public ATextView getOne(Context context) {
        ATextView view;notifyObservers();
        if(pool.isEmpty()) {
            view = new ATextView(context);
            addObserver(view);
        } else {
            view = pool.remove();
        }
        return view;
    }

    public void notifyLifecycleChange(LifecycleInfo info) {
        setChanged();
        notifyObservers(info);
    }


    public FragmentTaskView getF(String activity) {
        return map.get(activity);
    }

    public FragmentTaskView addF(Context context, String activity) {
        FragmentTaskView view = new FragmentTaskView(context);
        map.put(activity, view);
        return view;
    }

    public void removeF(String activity) {
        map.remove(activity);
    }

    public void clearF() {
        map.clear();
    }
}

作者：rome753
链接：https://www.jianshu.com/p/c34483bb5c0f
来源：简书
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