黑莓 - 听取启动和前台应用的后台应用程序

Question

我想创建一个后台应用程序，它可以监听哪些应用程序被启动并移到前台。

请回复，如果问题不清楚我会再次解释。

谢谢。

- Hare-Krishna

Answer 1

以下是您可以做的事情：

• use ApplicationManager.getForegroundProcessId()
• use ApplicationManager.getVisibleApplications() to get all running apps
• use ApplicationManager.getProcessId() to search for app by process id

• do this in TimerTask with defined period

  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);
      }
  }
  }
  

- Maksym Gontar

---

谢谢您的回复...除此之外，是否有任何Listener API或任何类型的事件，通过它我们将获得当前调用的前台应用程序。 - Hare-Krishna

如果这是你的应用程序，你可以随时使用http://www.blackberry.com/developers/docs/4.5.0api/net/rim/device/api/system/Application.html#activate%28%29事件...但在其他情况下，我看不到任何选择。 - Maksym Gontar