android - Android 中的线程阻塞 UI

Question

我正在使用 Android 蓝牙指南中的示例代码，可在此处找到 http://developer.android.com/guide/topics/connectivity/bluetooth.html在“作为客户端连接”下。

private class ConnectThread extends Thread {
private final BluetoothSocket mmSocket;
private final BluetoothDevice mmDevice;

public ConnectThread(BluetoothDevice device) {
    // Use a temporary object that is later assigned to mmSocket,
    // because mmSocket is final
    BluetoothSocket tmp = null;
    mmDevice = device;

    // Get a BluetoothSocket to connect with the given BluetoothDevice
    try {
        // MY_UUID is the app's UUID string, also used by the server code
        tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
    } catch (IOException e) { }
    mmSocket = tmp;
}

public void run() {
    // Cancel discovery because it will slow down the connection
    mBluetoothAdapter.cancelDiscovery();

    try {
        // Connect the device through the socket. This will block
        // until it succeeds or throws an exception
        mmSocket.connect();
    } catch (IOException connectException) {
        // Unable to connect; close the socket and get out
        try {
            mmSocket.close();
        } catch (IOException closeException) { }
        return;
    }

    // Do work to manage the connection (in a separate thread)
    manageConnectedSocket(mmSocket);
}

/** Will cancel an in-progress connection, and close the socket */
public void cancel() {
    try {
        mmSocket.close();
    } catch (IOException e) { }
}

在我的 onCreate 中，我调用

protected void onCreate(Bundle savedInstanceState) {
    setContentView(R.layout.activity_main);
    super.onCreate(savedInstanceState);
    connectionManager= new ConnectionManager(this);
    connectionManager.start();

connectionManager 启动一个 ConnectThread 并且连接线程成功连接到另一个蓝牙设备。但是，直到 ConnectThread 返回时才会呈现布局(确切地说，当 mmSocket.connect() 停止阻塞时)。我怎样才能让布局首先显示？

Answer 1

与其从 UI 线程创建连接管理器，不如在工作线程中创建它，如下所示:

protected void onCreate(Bundle savedInstanceState) {
setContentView(R.layout.activity_main);
super.onCreate(savedInstanceState);
new Thread(new Runnable() {

            @Override
            public void run() {
               connectionManager= new ConnectionManager(YourActivity.this);
               connectionManager.start();
            }
        }).start();

这样您就永远不会阻塞 UI 线程，希望这对您有所帮助...

问候!