Android前后台任务切换

秒速五厘米 2022-12-10 07:27 202阅读 0赞

#### 一、判断APP是否在前台运行 ####

public static boolean isRunningForeground(Context context) { 
            ActivityManager activityManager = (ActivityManager)context.getSystemService(Context.ACTIVITY_SERVICE);
            List<ActivityManager.RunningAppProcessInfo> appProcessInfos = activityManager.getRunningAppProcesses();
            // 枚举进程
            for (ActivityManager.RunningAppProcessInfo appProcessInfo : appProcessInfos) { 
                if (appProcessInfo.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND) { 
                    if (appProcessInfo.processName.equals(context.getApplicationInfo().processName)) { 
                        return true;
                    }
                }
            }
            return false;
        }

#### 二、将APP切换到前台 ####

//如果APP是在后台运行
    if (!AllUtils.isRunningForeground(this)) { 
          //获取ActivityManager
          ActivityManager mAm = (ActivityManager) getSystemService(ACTIVITY_SERVICE);
          //获得当前运行的task
          List<ActivityManager.RunningTaskInfo> taskList = mAm.getRunningTasks(100);
          for (ActivityManager.RunningTaskInfo rti : taskList) { 
              //找到当前应用的task，并启动task的栈顶activity，达到程序切换到前台
              if (rti.topActivity.getPackageName().equals(getPackageName())) { 
                  mAm.moveTaskToFront(rti.id, 0);
                  return;
              }
          }
          //若没有找到运行的task，用户结束了task或被系统释放，则重新启动mainactivity
          Intent resultIntent = new Intent(MainActivity.this, MainActivity.class);
          resultIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_SINGLE_TOP);
          startActivity(resultIntent);
      }

#### 三、需要的权限 ####

<uses-permission android:name="android.permission.GET_TASKS"/>
    <uses-permission android:name="android.permission.INTERACT_ACROSS_USERS_FULL"/>
    <uses-permission android:name="android.permission.GET_TOP_ACTIVITY_INFO"/>
    <uses-permission android:name="android.permission.REORDER_TASKS"/>