@Override protected void onStop() { if (!isAppOnForeground()) { Debug.i("dwy", "enter background"); mIsBackground = true; } else { Debug.i("dwy", "foreground"); mIsBackground = false; }

Judge is App in background when onStop() get called.

public boolean isAppOnForeground() { // Returns a list of application processes that are running on the // device ActivityManager activityManager = (ActivityManager) getApplicationContext().getSystemService(Context.ACTIVITY_SERVICE); String packageName = getApplicationContext().getPackageName(); List<ActivityManager.RunningAppProcessInfo> appProcesses = activityManager .getRunningAppProcesses(); if (appProcesses == null) return false; for (ActivityManager.RunningAppProcessInfo appProcess : appProcesses) { // The name of the process that this object is associated with. if (appProcess.processName.equals(packageName) && appProcess.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND) { return true; } } return false; }

方法二：

/** * 需要权限:android.permission.GET_TASKS * * @param context * @return */ public boolean isApplicationBroughtToBackground(Context context) { ActivityManager am = (ActivityManager) context .getSystemService(Context.ACTIVITY_SERVICE); List<RunningTaskInfo> tasks = am.getRunningTasks(1); if (tasks != null && !tasks.isEmpty()) { ComponentName topActivity = tasks.get(0).topActivity; Debug.i(TAG, "topActivity:" + topActivity.flattenToString()); Debug.f(TAG, "topActivity:" + topActivity.flattenToString()); if (!topActivity.getPackageName().equals(context.getPackageName())) { return true; } } return false; }