Question

我不完全确定如何正确使用ConnectionFactory，但这是我的ImageThread示例，每次有图像时调用ConnectionFactory，在任何给定的屏幕上都有一堆。

public class ImageThread extends Thread {
private String url;
private HttpConnection httpConn;
private InputStream is;
private JSONArray array;
private Bitmap image;
private ImageThreadCallback c;


private static boolean hasImageCache = false;
private static MultiMap imageCache;

public ImageThread(String url, ImageThreadCallback c, String ident){
    System.out.println("Connection begin!");
    this.url = url;
    this.c = c;

}

public void notifyUs(){
    this.c.update(image);
}


public void run(){

    myConnectionFactory connFact = new myConnectionFactory();
    ConnectionDescriptor connDesc;

    connDesc = connFact.getConnection(url);
    System.out.println("Connection factory!");
    if(connDesc != null)
    {
        System.out.println("Connection not null!");
        httpConn = (HttpConnection) connDesc.getConnection();
        try {
            httpConn.setRequestMethod(HttpConnection.GET);
        } catch (IOException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }
        is = null;



        try
        {
            final int iResponseCode = httpConn.getResponseCode();
            UiApplication.getUiApplication().invokeLater(new Runnable()
            {

                public void run()
                {
                    System.out.println("Connection in run!");
                     // Get InputConnection and read the server's response
                    InputConnection inputConn = (InputConnection) httpConn;
                    try {
                        is = inputConn.openInputStream();
                        System.out.println("Connection got inputstream!");
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                    byte[] data = null;
                    try {
                        data = IOUtilities.streamToBytes(is);
                        System.out.println("Connection got data!");
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }


                     EncodedImage hai = EncodedImage.createEncodedImage(data, 0, data.length);

                    image = hai.getBitmap();
                    notifyUs();


                }

            });
        }
        catch(IOException e)
        {
            System.err.println("Caught IOException: " + e.getMessage());
        }
    }

}

}

我知道这个例子与示例相同，但是应该为ImageThread的每个实例调用ConnectionFactory吗？我问这个问题是因为我的应用程序在使用它时会突然失去连接。输入/输出图标不再闪烁。我在想它可能是对ConnectionFactory的误用？

有什么想法吗？

Answer 1

不，除非您想要更改连接首选项（如连接模式或超时），否则无需创建新实例。

连接丢失对我来说似乎是一个不同的问题。重用收集意味着您将节省堆内存，但我认为它与其他内容无关。您可以尝试在设备上进行调试，并查看您获得的HTTP错误代码。

Answer 2

问题是您正在对应用程序的事件线程执行I / O操作。当您使用invokeLater（Runnable r）时，r将在Application的事件线程上执行。很可能，Blackberry运行时会终止该应用程序。

就我看到你的代码而言，你不必创建传递给invokeLater（）的匿名内部类Runnable。你可以这样做：

if(connDesc != null)
    {
        System.out.println("Connection not null!");
        httpConn = (HttpConnection) connDesc.getConnection();
        try {
            httpConn.setRequestMethod(HttpConnection.GET);
        } catch (IOException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }
        is = null;



        try
        {
            final int iResponseCode = httpConn.getResponseCode();
                   System.out.println("Connection in run!");
                     // Get InputConnection and read the server's response
                    InputConnection inputConn = (InputConnection) httpConn;
                    try {
                        is = inputConn.openInputStream();
                        System.out.println("Connection got inputstream!");
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                    byte[] data = null;
                    try {
                        data = IOUtilities.streamToBytes(is);
                        System.out.println("Connection got data!");
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }


                     EncodedImage hai = EncodedImage.createEncodedImage(data, 0, data.length);

                    image = hai.getBitmap();
                    notifyUs();
        catch(IOException e)
        {
            System.err.println("Caught IOException: " + e.getMessage());
        }

尽管如此，我发现代码存在其他问题，如果你做出我提到的修正，那也没关系。

黑莓：打开ConnectionFactory太多次了？

2 个答案: