J2ME:从服务器下载图像并保存到移动设备

Question

我正在尝试从服务器下载图像并将图像保存在手机上。我可以下载图像，但我需要调整图像大小，然后将图像存储到手机上。

代码是这样的。

public void requestPlatform(String strURL) throws IOException {
try {

    System.out.println("requestPlatform");

      byte [] imageBytes = null;

    if ((im = getImage1(strURL)) != null) {
        im=resizeImage(im, width, height);
           if(im!=null)
        {
            System.out.println("Image");
        }

        else
            System.out.println("NoImage");
        imageBytes=get_Byte_Array(im);

        fileCon=(FileConnection)Connector.open("file:///root1/photos/diwali1.jpg",Connector.READ_WRITE);

        fileCon.create();
        if(fileCon.exists())
        {

            System.out.println("File created");
        }
        else
        {
            System.out.println("File not created");
        }

        out = fileCon.openDataOutputStream();


          if(imageBytes!=null)
        {
            out.write(imageBytes, 0, imageBytes.length);
        }
        if(out!=null)
        {
            out.close();
        }
        if(fileCon!=null)
        {
            fileCon.close();
        }
        im2=Image.createImage(imageBytes, 0, imageBytes.length);

        canvas.repaint();
    }
} catch (Exception e) {
    System.err.println("Msg: " + e.toString());
}
}

public byte[] get_Byte_Array(Image img) {

    int[] imgRgbData = new int[img.getWidth() * img.getHeight()];
    byte[] imageData2 = null;
    try
    {
    img.getRGB( imgRgbData, 0, img.getWidth(), 0, 0, img.getWidth(), img.getHeight() );
    } catch( Exception e )
    {
    }
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    DataOutputStream dos = new DataOutputStream( baos );

    try{
    for( int i = 0; i < imgRgbData.length; i++ )
    {
    dos.writeInt( imgRgbData[i] );
    }

    imageData2 = baos.toByteArray();
    baos.close();
    dos.close();
    }catch(Exception e)
    {

    }
    return imageData2;
    }

问题是，当我试图调整图像大小，然后将其保存在手机上时，它只是创建了一个文件，但没有image.So，我认为当我将图像转换为byteArray时，可能有一些错误。

Answer 1

Image.createImage(Image image, int x, int y, int width, int height, int **transform**)

关于省钱。您可以将数据保存到RMS (这在所有J2ME手机上都是可能的)或文件系统(仅在使用JSR-75 FileConnection API的设备上)。

Answer 2

您可以使用它来调整图像的大小，但最好在服务器上调整它的大小，而不是在手机上执行此操作。您需要调整它以将图像大小调整为指定的宽度和高度。

private Image resizeImage(Image src) {
      int srcWidth = src.getWidth();
      int srcHeight = src.getHeight();
      Image tmp = Image.createImage(screenWidth, srcHeight);
      Graphics g = tmp.getGraphics();
      int ratio = (srcWidth << 16) / screenWidth;
      int pos = ratio/2;

      //Horizontal Resize        

      for (int x = 0; x < screenWidth; x++) {
          g.setClip(x, 0, 1, srcHeight);
          g.drawImage(src, x - (pos >> 16), 0, Graphics.LEFT | Graphics.TOP);
          pos += ratio;
      }

      Image resizedImage = Image.createImage(screenWidth, screenHeight);
      g = resizedImage.getGraphics();
      ratio = (srcHeight << 16) / screenHeight;
      pos = ratio/2;        

      //Vertical resize

      for (int y = 0; y < screenHeight; y++) {
          g.setClip(0, y, screenWidth, 1);
          g.drawImage(tmp, 0, y - (pos >> 16), Graphics.LEFT | Graphics.TOP);
          pos += ratio;
      }
      return resizedImage;

  }//resize image

这段代码取自here

Answer 3

这是我使用的一个很棒的图像调整脚本。希望它能满足你的需求。

public Image ResizeImage(Image image, int resizedWidth, int resizedHeight) {  
    int[] in = null, out = null;  

    int width = image.getWidth(), height = image.getHeight();  
    in = new int[width];   

    int i=0;  
    int dy,dx;   
    out = new int[resizedWidth * resizedHeight];   

    for (int y = 0; y < resizedHeight; y++)   
    {   
        dy = y * height / resizedHeight;  

        image.getRGB(in,0,width,0,dy,width,1);   


        for (int x = 0; x < resizedWidth; x++)   
        {   
        dx = x * width / resizedWidth;   

        out[(resizedWidth * y) + x] = in[dx];  
        }   
    }   
    Image resized = Image.createRGBImage(out,resizedWidth,resizedHeight,true);  
    return resized;   
}