蓝牙发送和接收文本数据

我是Android开发的新手，我想创建一个使用蓝牙发送和接收文本的应用程序。 我得到了关于发送文本在逻辑上工作的一切，但当我尝试在手机中测试它时，我看不到界面。

这是Main Activity代码

 import android.support.v7.app.ActionBarActivity; import android.support.v7.app.ActionBar; import android.support.v4.app.Fragment; import android.os.Bundle; import android.view.LayoutInflater; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.view.ViewGroup; import android.os.Build; import android.app.Activity; import android.bluetooth.BluetoothAdapter; import android.bluetooth.BluetoothDevice; import android.bluetooth.BluetoothSocket; import android.content.Intent; import android.os.Bundle; import android.os.Handler; import android.view.View; import android.widget.TextView; import android.widget.EditText; import android.widget.Button; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.util.Set; import java.util.UUID; public class MainActivity extends ActionBarActivity { BluetoothAdapter mBluetoothAdapter; BluetoothSocket mmSocket; BluetoothDevice mmDevice; OutputStream mmOutputStream; InputStream mmInputStream; Thread workerThread; EditText myTextbox; TextView myLabel; byte[] readBuffer; int readBufferPosition; int counter; volatile boolean stopWorker; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); try { Button sendButton = (Button) findViewById(R.id.send); Button openButton = (Button) findViewById(R.id.open); myTextbox = (EditText) findViewById(R.id.editText); myLabel = (TextView) findViewById(R.id.textView); openButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { try { findBT(); openBT(); } catch (IOException ex) { } } }); // send data typed by the user to be printed sendButton.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { try { sendData(); } catch (IOException ex) { } } }); } catch (NullPointerException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } } // This will find a bluetooth device void findBT() { try { mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter(); if (mBluetoothAdapter == null) { myLabel.setText("No bluetooth adapter available"); } if (!mBluetoothAdapter.isEnabled()) { Intent enableBluetooth = new Intent( BluetoothAdapter.ACTION_REQUEST_ENABLE); startActivityForResult(enableBluetooth, 0); } Set pairedDevices = mBluetoothAdapter .getBondedDevices(); if (pairedDevices.size() > 0) { for (BluetoothDevice device : pairedDevices) { // Salaxy S4 is the name of the bluetooth device if (device.getName().equals("Galaxy S4")) { mmDevice = device; break; } } } myLabel.setText("Bluetooth Device Found"); } catch (NullPointerException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } } // Tries to open a connection to the bluetooth device void openBT() throws IOException { try { // Standard SerialPortService ID UUID uuid = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb"); mmSocket = mmDevice.createRfcommSocketToServiceRecord(uuid); mmSocket.connect(); mmOutputStream = mmSocket.getOutputStream(); mmInputStream = mmSocket.getInputStream(); beginListenForData(); myLabel.setText("Bluetooth Opened"); } catch (NullPointerException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } } // After opening a connection to bluetooth device, // we have to listen and check if a data were sent to be printed. void beginListenForData() { try { final Handler handler = new Handler(); // This is the ASCII code for a newline character final byte delimiter = 10; stopWorker = false; readBufferPosition = 0; readBuffer = new byte[1024]; workerThread = new Thread(new Runnable() { public void run() { while (!Thread.currentThread().isInterrupted() && !stopWorker) { try { int bytesAvailable = mmInputStream.available(); if (bytesAvailable > 0) { byte[] packetBytes = new byte[bytesAvailable]; mmInputStream.read(packetBytes); for (int i = 0; i < bytesAvailable; i++) { byte b = packetBytes[i]; if (b == delimiter) { byte[] encodedBytes = new byte[readBufferPosition]; System.arraycopy(readBuffer, 0, encodedBytes, 0, encodedBytes.length); final String data = new String( encodedBytes, "US-ASCII"); readBufferPosition = 0; handler.post(new Runnable() { public void run() { myLabel.setText(data); } }); } else { readBuffer[readBufferPosition++] = b; } } } } catch (IOException ex) { stopWorker = true; } } } }); workerThread.start(); } catch (NullPointerException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } } /* * This will send data to be printed by the bluetooth */ void sendData() throws IOException { try { // the text typed by the user String msg = myTextbox.getText().toString(); msg += "\n"; mmOutputStream.write(msg.getBytes()); // tell the user data were sent myLabel.setText("Data Sent"); } catch (NullPointerException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } } } 

这是我的Fragment_main

我的Manifest

所以我想知道：

1. 为什么我看不到界面并测试我的代码？
2. 如何在应用程序内部接收文本？

感谢所有帮助人员。

Answer 1

一步一步来。

 setContentView(R.layout.activity_main); 

将设置视图的内容，我假设它在Fragment_main中的定义应该是fragment_main作为它的XML文件。 所以如果你改成它

 setContentView(R.layout. fragment_main); 

你应该能够看到用户界面。