更新的Andr​​oid UI使用线程 [英] Updating Android UI using threads

问题描述

我写一个Android应用程序的聊天，我正在听的连接，我收到的数据，我可以看到它在Log.d，但每当我尝试更新我的UI的应用程序崩溃..在code是

I am writing an android chat app, i am listening for connections and i receive data and i can see it in the Log.d, but whenever i try to update my UI the application crash .. the code is

    private class chatReceiver implements Runnable {
    @Override
    public void run() {
        try {
            skt = new DatagramSocket(Integer.parseInt(Main.prefs.getString("port_number", "5432")));
            DatagramPacket rcvPkt = new DatagramPacket(rcvBuf,rcvBuf.length);
            String ack = "Hello from our SimpleUDPServer";
            byte[] sndBuf = ack.getBytes();
            while (true) {
                Log.d("Server received: " ,"entered loop");
                skt.receive(rcvPkt);
                String rcvMsg = new String(rcvBuf, 0, rcvPkt.getLength(), "UTF-8");
                Log.d("Server received: " ,"receiving" + rcvMsg);
                if (rcvMsg != null) {
                    Log.d("Server received: " ,"not equal null");
                    // I want to update my UI here
                }
                DatagramPacket k = new DatagramPacket(sndBuf, sndBuf.length,
                        rcvPkt.getAddress(), rcvPkt.getPort());
                skt.send(k);
                Log.d("Server sent" ,ack);

            }
        } catch (IOException ex) {
            Log.d("ThreadStart", "Error Starting thread" + ex.getStackTrace());
        }

    }
} 

和更新UI我使用：

public static void updateUI(Bubble b, View itemView) {

    TextView txt_display_name = (TextView) itemView
            .findViewById(R.id.display_name);
    txt_display_name.setText(b.getDisplay_name());
    TextView txt_chat_body = (TextView) itemView
            .findViewById(R.id.chat_body);
    txt_chat_body.setText(b.getChat_body());
    TextView txt_creation_date = (TextView) itemView
            .findViewById(R.id.creation_date);
    txt_creation_date.setText(b.getCreation_time());
}

我的应用程序不断崩溃！

my app keeps on crashing !!

推荐答案

您不能从后台线程触摸UI线程什么，要做到这一点使用的处理程序，初始化后台线程传递一个Handler对象。当数据到达使用的处理程序将消息发送到用户界面。在UI时从后台线程的消息传出，刚刚更新了意见。

you cannot touch anything in the ui thread from a background thread, to do that use Handlers, initialize your background thread passing it a Handler object. When data arrives use the handler to send a message to the ui. In the ui when the message from the background thread comes, just update the Views.

这样的事情...

在后台线程：

if(dataArrives){
    Message msg = handler.obtainMessage();
    msg.what = UPDATE_IMAGE;
    msg.obj = bitmap;
    msg.arg1 = index;
    handler.sendMessage(msg);
}

在UI线程：

final Handler handler = new Handler(){
  @Override
  public void handleMessage(Message msg) {
    if(msg.what==UPDATE_IMAGE){
      images.get(msg.arg1).setImageBitmap((Bitmap) msg.obj);
    }
    super.handleMessage(msg);
  }
};

和传递处理的bakground THEAD

and pass the handler to the bakground thead

这篇关于更新的Andr​​oid UI使用线程的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！