Android get all Activity

1 way one

    public void getAllActivity() {
    
    
        PackageManager packageManager = getPackageManager();
        PackageInfo packageInfo = null;
        try {
    
    
            packageInfo = packageManager.getPackageInfo(
                    getPackageName(), PackageManager.GET_ACTIVITIES);
            //所有的Activity 
            ActivityInfo[] activities = packageInfo.activities;
            for (ActivityInfo activity :activities ) {
    
    
                Class<?> aClass = Class.forName(activity.name);
            }

        } catch (PackageManager.NameNotFoundException | ClassNotFoundException e) {
    
    
            e.printStackTrace();
        }
    }

2 way 2 reflection

    private static List<Activity> getActivitiesByApplication(Application application) {
    
    
        List<Activity> list = new ArrayList<>();
        try {
    
    
            Class<Application> applicationClass = Application.class;
            Field mLoadedApkField = applicationClass.getDeclaredField("mLoadedApk");
            mLoadedApkField.setAccessible(true);
            Object mLoadedApk = mLoadedApkField.get(application);
            Class<?> mLoadedApkClass = mLoadedApk.getClass();
            Field mActivityThreadField = mLoadedApkClass.getDeclaredField("mActivityThread");
            mActivityThreadField.setAccessible(true);
            Object mActivityThread = mActivityThreadField.get(mLoadedApk);
            Class<?> mActivityThreadClass = mActivityThread.getClass();
            Field mActivitiesField = mActivityThreadClass.getDeclaredField("mActivities");
            mActivitiesField.setAccessible(true);
            Object mActivities = mActivitiesField.get(mActivityThread);
            // 注意这里一定写成Map，低版本这里用的是HashMap，高版本用的是ArrayMap
            if (mActivities instanceof Map) {
    
    
                @SuppressWarnings("unchecked")
                Map<Object, Object> arrayMap = (Map<Object, Object>) mActivities;
                for (Map.Entry<Object, Object> entry : arrayMap.entrySet()) {
    
    
                    Object value = entry.getValue();
                    Class<?> activityClientRecordClass = value.getClass();
                    Field activityField = activityClientRecordClass.getDeclaredField("activity");
                    activityField.setAccessible(true);
                    Object o = activityField.get(value);
                    list.add((Activity) o);
                }
            }
        } catch (Exception e) {
    
    
            e.printStackTrace();
            list = null;
        }
        return list;
    }

3 Get the Activity at the top of the stack

    //获取栈顶Activity及其所属进程
    public static String getTopActivityNameAndProcessName(Context context) {
    
    
        String processName = null;
        String topActivityName = null;
        ActivityManager activityManager =
                (ActivityManager) (context.getSystemService(android.content.Context.ACTIVITY_SERVICE));
        List<ActivityManager.RunningTaskInfo> runningTaskInfos = activityManager.getRunningTasks(1);
        if (runningTaskInfos != null) {
    
    
            ActivityManager.RunningTaskInfo runningTaskInfo = runningTaskInfos.get(0);
            ComponentName f = runningTaskInfo.topActivity;
            String topActivityClassName = f.getClassName();
            String temp[] = topActivityClassName.split("\\.");
            //栈顶Activity的名称
            topActivityName = temp[temp.length - 1];
            int index = topActivityClassName.lastIndexOf(".");
            //栈顶Activity所属进程的名称
            processName = topActivityClassName.substring(0, index);
            System.out.println("---->topActivityName=" + topActivityName + ",processName=" + processName);

        }
        return topActivityName;
    }