黑莓 - 带动画的加载/等待屏幕

Question

有没有办法在黑莓中显示带有动画的 "加载"屏幕？

选项:

• PME动画内容
• 多线程+图像集+定时器/计数器
• 标准轮辋api
• 另一种方式

这是什么？

谢谢!

Answer 1

费尔明,安东尼+1.谢谢大家,你给了我答案的一部分.
我的最终解决方案

1.创建或生成(免费的Ajax加载gif生成器)动画并将其添加到项目中.

2.创建ResponseCallback接口(参见Coderholic - Blackberry WebBitmapField)以接收线程执行结果:

public interface ResponseCallback {
    public void callback(String data);  
}

3.创建一个类来处理后台线程作业.在我的情况下,这是http请求:

public class HttpConnector 
{
  static public void HttpGetStream(final String fileToGet,
    final ResponseCallback msgs) {
    Thread t = new Thread(new Runnable() {
      public void run() {
        HttpConnection hc = null;
    DataInputStream din = null;
    try {
      hc = (HttpConnection) Connector.open("http://" + fileToGet);
      hc.setRequestMethod(HttpsConnection.GET);
      din = hc.openDataInputStream();
      ByteVector bv = new ByteVector();
      int i = din.read();
      while (-1 != i) {
        bv.addElement((byte) i);
        i = din.read();
      }
      final String response = new String(bv.toArray(), "UTF-8");
      UiApplication.getUiApplication().invokeLater(
        new Runnable() {
          public void run() {
        msgs.callback(response);
              }
            });
    } 
        catch (final Exception e) {
          UiApplication.getUiApplication().invokeLater(
            new Runnable() {
              public void run() {
                msgs.callback("Exception (" + e.getClass() + "): " 
                  + e.getMessage());
              }
            });
        } 
        finally {
          try {
            din.close();
            din = null;
            hc.close();
            hc = null;
          }
          catch (Exception e) {
          }
        }
      }
    });
  t.start();
  }
}

4.创建WaitScreen(FullScreen和AnimatedGIFField与ResponseCallback接口的混合):

public class WaitScreen extends FullScreen implements ResponseCallback 
{
    StartScreen startScreen;
    private GIFEncodedImage _image;
    private int _currentFrame;
    private int _width, _height, _xPos, _yPos;
    private AnimatorThread _animatorThread;
    public WaitScreen(StartScreen startScreen) {
        super(new VerticalFieldManager(), Field.NON_FOCUSABLE);
        setBackground(
            BackgroundFactory.createSolidTransparentBackground(
                Color.WHITE, 100));
        this.startScreen = startScreen;
        EncodedImage encImg = 
          GIFEncodedImage.getEncodedImageResource("ajax-loader.gif");
        GIFEncodedImage img = (GIFEncodedImage) encImg;

        // Store the image and it's dimensions.
        _image = img;
        _width = img.getWidth();
        _height = img.getHeight();
        _xPos = (Display.getWidth() - _width) >> 1;
        _yPos = (Display.getHeight() - _height) >> 1;
        // Start the animation thread.
        _animatorThread = new AnimatorThread(this);
        _animatorThread.start();
        UiApplication.getUiApplication().pushScreen(this);
    }

    protected void paint(Graphics graphics) {
        super.paint(graphics);
            // Draw the animation frame.
            graphics
              .drawImage(_xPos, _yPos, _image
                .getFrameWidth(_currentFrame), _image
                  .getFrameHeight(_currentFrame), _image,
                _currentFrame, 0, 0);
    }

    protected void onUndisplay() {
        _animatorThread.stop();
    }

    private class AnimatorThread extends Thread {
        private WaitScreen _theField;
        private boolean _keepGoing = true;
        private int _totalFrames, _loopCount, _totalLoops;
        public AnimatorThread(WaitScreen _theScreen) {
            _theField = _theScreen;
            _totalFrames = _image.getFrameCount();
            _totalLoops = _image.getIterations();

        }

        public synchronized void stop() {
            _keepGoing = false;
        }

        public void run() {
            while (_keepGoing) {
                // Invalidate the field so that it is redrawn.
                UiApplication.getUiApplication().invokeAndWait(
                  new Runnable() {
                    public void run() {
                        _theField.invalidate();
                    }
                });
                try {
                  // Sleep for the current frame delay before
                  // the next frame is drawn.
                  sleep(_image.getFrameDelay(_currentFrame) * 10);
                } catch (InterruptedException iex) {
                } // Couldn't sleep.
                // Increment the frame.
                ++_currentFrame;
                if (_currentFrame == _totalFrames) {
                  // Reset back to frame 0 
                  // if we have reached the end.
                  _currentFrame = 0;
                  ++_loopCount;
                  // Check if the animation should continue.
                  if (_loopCount == _totalLoops) {
                    _keepGoing = false;
                  }
                }
            }
        }

    }

    public void callback(String data) {
        startScreen.updateScreen(data);
        UiApplication.getUiApplication().popScreen(this);
    }
}

5.最后,创建"开始"屏幕以调用HttpConnector.HttpGetStream并显示WaitScreen:

public class StartScreen extends MainScreen
{
    public RichTextField text;
    WaitScreen msgs;
    public StartScreen() {       
        text = new RichTextField();
        this.add(text);
    }

    protected void makeMenu(Menu menu, int instance) {
        menu.add(runWait);
        super.makeMenu(menu, instance);
    }

    MenuItem runWait = new MenuItem("wait", 1, 1) {
        public void run() {
            UiApplication.getUiApplication().invokeLater(
                new Runnable() {
                    public void run() {
                        getFile();
                    }
            });             
        }
    };

    public void getFile() {
        msgs = new WaitScreen(this);
        HttpConnector.HttpGetStream(
            "stackoverflow.com/faq", msgs);                 
    }

    //you should implement this method to use callback data on the screen.
    public void updateScreen(String data)
    {
        text.setText(data);
    }
}

更新:另一个解决方案naviina.eu:本机BlackBerry应用程序中的Web2.0/Ajax样式加载弹出窗口