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我们有一个主要活动，其中有一个文本视图，要求它从LAN中的TCP服务器自动检索数据。 我们在updateData（）中启用AsyncTask来调用Connect调用Handler以更新名为mTvVoc的TextView，并通过beginConnect（）刷新连接。Android AsyncTask +处理程序，没有数据更新到主要活动UI
问题是mTvVoc没有更新，它似乎AsyncTask不能按预期方式工作？
public class MainActivity extends Activity {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
updateData();
}
public void updateData(final String order) {
Connect(HOST, PORT, order);
new AsyncTask<Void, Void, Void>() {
@Override
protected Void doInBackground(Void... params) {
System.out.println("get data from order--->" + order);
beginConnect(HOST, PORT, order);
return null;
}
@Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
}
}.execute();
}
public String Connect(final String HOST, final int PORT, final String OderType) {
new Thread(new Runnable() {
@Override
public void run() {
try {
socket = new Socket(HOST, PORT);
bufferedInputStream = new BufferedInputStream(socket.getInputStream());
System.out.println("bufferedInputStream--->" + bufferedInputStream);
printWriter = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream())),
true);
if (socket.isConnected()) {
if (!socket.isOutputShutdown()) {
printWriter.println(Integer.toHexString(Integer
.parseInt(OderType)));
}
}
while (true) {
if (!socket.isClosed() && socket.isConnected() && !socket.isInputShutdown()) {
int temp = 0;
byte[] buf = new byte[1024];
while ((temp = bufferedInputStream.read(buf)) != -1) {
isConn(socket);
Log.d("Data received", new String(buf, 0, temp));
acceptinfo = new String(buf, 0, temp);
System.out.println("Data received====》" + acceptinfo);
Message message = new Message();
message.what = 1;
message.obj = acceptinfo;
handler.sendMessage(message);
}
}
}
} catch (UnknownHostException e) {
System.out.println("UnknownHostException-->connection failed");
stopConnect();
e.printStackTrace();
} catch (IOException e) {
System.out.println("IOException-->connection failed");
stopConnect();
e.printStackTrace();
}
}
}).start();
return acceptinfo;
}
public String beginConnect(final String HOST, final int PORT, final String OderType) {
new Thread(new Runnable() {
@Override
public void run() {
try {
socket = new Socket(HOST, PORT);
bufferedInputStream = new BufferedInputStream(socket.getInputStream());
System.out.println("bufferedInputStream--->" + bufferedInputStream);
printWriter = new PrintWriter(new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream())),
true);
if (socket.isConnected()) {
if (!socket.isOutputShutdown()) {
printWriter.println(Integer.toHexString(Integer.parseInt(OderType)));
}
}
} catch (UnknownHostException e) {
System.out.println("UnknownHostException-->connection failed");
stopConnect();
e.printStackTrace();
} catch (IOException e) {
System.out.println("IOException-->connection failed");
stopConnect();
e.printStackTrace();
}
}
}).start();
return acceptinfo;
}
public Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
Log.i("message", msg.obj.toString());
if (msg.what == 0) {
mIvContent.setImageResource(R.drawable.wangluo_gray);
Toast.makeText(MainActivity.this, "Server connection failed", Toast.LENGTH_SHORT).show();
reGetData();
}
if (msg.what == 1) {
String info = msg.obj.toString();
if (info.length() != 18) {
mIvContent.setImageResource(R.drawable.wangluo_gray);
System.out.println("data verification failed");
reGetData();
return;
}
String iszeroupString = info.substring(1, 3);
String temperature = Integer.toString(Integer.parseInt(info.substring(3, 5), 16));
String vocValue = Integer.toString(Integer.parseInt(info.substring(7, 9), 16));
mTvVoc.setText(getVOC((Integer.valueOf(vocValue)/100.00)));
}
}
}
很奇怪你有一个连接（）和一个连接到服务器的beginConnect（）。所以两个客户端实例。你为什么这样做？没有意义。 – greenapps
而你在doInBackground中开始新的主题是完全错误的。只需将代码直接放入doInBackground中，而无需将其包装在线程中。并且不要两次连接。那么除非你有很好的理由这样做，但你没有告诉我们。使用线程或异步任务。不是都。 – greenapps
所以我需要删除beginConnect（）？ – Freshman