Blackberry 不支持 getSnapshot

Question

我在使用 VideoControl.getSnapshot() 方法拍照时遇到问题。它总是抛出异常：getSnapshot not Supported。我将 JRE 5.0.0 与 Eclipse 和 BlackBerry® Java® SDK 5.0 插件结合使用。

我首先要做的是使用命令 System.getProperty("video.snapshot.encodings") 列出所选 Blackberry SmartPhone 支持的编码（粗体 9700），然后从列表中选择一种编码并将其作为 getSnapshot 参数传递。

我已经在几个黑莓上进行了测试，并且抛出了相同的异常。

部分代码：

mPlayer = Manager.createPlayer("capture://video?encoding=video/3gpp");

mPlayer.realize();

mPlayer = Manager.createPlayer("capture://video?encoding=video/3gpp");

mPlayer.start();

videoControl = (VideoControl)mPlayer.getControl("VideoControl");

Field cameraView = (Field) videoControl.initDisplayMode(VideoControl.USE_GUI_PRIMITIVE, "net.rim.device.api.ui.Field");

Thread.sleep(1000);

UiApplication.getUiApplication().pushScreen(new TempScreen(cameraView));

byte[] snapShot = videoControl.getSnapshot("encoding=jpeg&width=480&height=360&quality=superfine");

Bitmap image = Bitmap.createBitmapFromBytes(snapShot, 0, snapShot.length, 1);

UiApplication.getUiApplication().pushScreen(new TempScreen(image));

}catch (MediaException e){
UiApplication.getUiApplication().pushScreen(new TempScreen("Exception: " + e.getMessage())); }

catch (IOException e){
UiApplication.getUiApplication().pushScreen(new TempScreen("IO Exception: " + e.getMessage())); 
}

catch (InterruptedException e){UiApplication.getUiApplication().pushScreen(new TempScreen("Interrupted Exception: "+ e.getMessage()));}

Answer 1

不确定我的答案在半年多后是否真实，但可能会有用。

您可以尝试使用 Thread.sleep(1000);在 getSnapshot() 调用之前。
该问题可能与以下事实有关：“在调用 getSnapShot() 之前，取景器实际上必须在屏幕上可见。”

因此，如果您在之后立即调用 getSnapshot

UiApplication.getUiApplication().pushScreen(new TempScreen(cameraView));

the camera isn't prepared for the next shot.

另外，您真的确定您的设备完全支持 getSnapshot() API 吗？尽管 API 定义了此方法，但某些制造商可能不支持它。您是否在测试 getSnapshot() 的同一设备上运行 System.getProperty("video.snapshot.encodings") ？

Answer 2

  Player _p;
  VideoControl _vc ;
  RecordControl _rc ;
  String PATH;
  FileConnection fileconn;
  Object canvas= new Object();

  public static boolean SdcardAvailabulity() {
         String root = null;
         Enumeration e = FileSystemRegistry.listRoots();
         while (e.hasMoreElements()) {
             root = (String) e.nextElement();
             if( root.equalsIgnoreCase("sdcard/") ) {
                 return true;
             }else if( root.equalsIgnoreCase("store/") ) {
                 return false;
             }
         }
         class MySDListener implements FileSystemListener {
             public void rootChanged(int state, String rootName) {
                 if( state == ROOT_ADDED ) {
                     if( rootName.equalsIgnoreCase("sdcard/") ) {
                     }
                 } else if( state == ROOT_REMOVED ) {
                 }
             }
         }
         return true;
    }
protected boolean invokeAction(int action){
      boolean handled = super.invokeAction(action); 
      if(SdcardAvailabulity()){
          PATH = System.getProperty("fileconn.dir.memorycard.videos")+"Video_"+System.currentTimeMillis()+".3gpp";//here "str" having the current Date and Time;
      } else {
          PATH = System.getProperty("fileconn.dir.videos")+"Video_"+System.currentTimeMillis()+".3gpp"; 
      }
      if(!handled){
          if(action == ACTION_INVOKE){   
              try{     

                  if(_p!=null)
                      _p.close();  
              }catch(Exception e){
              }
          }
      }
    return handled;
  }
  public MyScreen(){
      setTitle("Video recording demo");
      ButtonField AddPhoto = new ButtonField("push",ButtonField.FOCUSABLE | ButtonField.FIELD_HCENTER | ButtonField.FIELD_VCENTER | DrawStyle.HCENTER | ButtonField.NEVER_DIRTY | Field.USE_ALL_WIDTH);
      FieldChangeListener PhotoListener = new FieldChangeListener() {
          public void fieldChanged(Field field, int context) {
              ButtonField  Button = (ButtonField) field;
              if (Button.getLabel().equals("push")){


              }
          }
      };
      AddPhoto.setChangeListener(PhotoListener);
      add(AddPhoto);
  }
}