BlackBerry - 後臺應用程序監聽開始和前臺應用程序

Question

我想創建後臺應用程序，它將監聽哪些應用程序已啓動，哪些應用程序已移至前臺。

請回復 如果問題不明確將再次解釋。

感謝

Answer 1

這是你可以做什麼：

• 使用ApplicationManager.getForegroundProcessId()
• 使用ApplicationManager.getVisibleApplications()來獲取所有正在運行的應用
• 使用ApplicationManager.getProcessId()搜索應用程序進程的ID

• 在TimerTask中定義期限

  public class AppListenerApp extends Application { 
  int mForegroundProcessId = -1; 
  
  public AppListenerApp() { 
      Timer timer = new Timer(); 
      timer.schedule(mCheckForeground, 2000, 2000);      
  } 
  
  public static void main(String[] args) { 
      AppListenerApp app = new AppListenerApp(); 
      app.enterEventDispatcher(); 
  } 
  
  TimerTask mCheckForeground = new TimerTask() { 
      public void run() { 
       int id = getForegroungProcessID(); 
       if(id != mForegroundProcessId) 
       { 
        mForegroundProcessId = id; 
        String name = 
         getAppNameByProcessId(mForegroundProcessId); 
        showMessage(name); 
       } 
      }; 
  }; 
  
  private int getForegroungProcessID() { 
      return ApplicationManager.getApplicationManager() 
        .getForegroundProcessId(); 
  } 
  
  private String getAppNameByProcessId(int id) { 
      String result = null; 
      ApplicationManager appMan = 
         ApplicationManager.getApplicationManager(); 
      ApplicationDescriptor appDes[] = 
         appMan.getVisibleApplications(); 
      for (int i = 0; i < appDes.length; i++) { 
       if (appMan.getProcessId(appDes[i]) == id) { 
        result = appDes[i].getName(); 
        break; 
       } 
      } 
      return result; 
  } 
  
  private void showMessage(String message) { 
      synchronized (Application.getEventLock()) { 
       Dialog dlg = new Dialog(Dialog.D_OK, message, 
           Dialog.OK, null, Manager.FIELD_HCENTER); 
       Ui.getUiEngine() 
           .pushGlobalScreen(dlg, 1, UiEngine.GLOBAL_QUEUE); 
      } 
  } 
  }