蓝牙发送和接收文本数据

Question

我是Android开发的新手，我想开发一个使用蓝牙发送和接收文本的应用程序。 从逻辑上讲，我已经获得了有关发送文本的所有信息，但是当我尝试在手机中对其进行测试时，看不到该界面。

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<BluetoothDevice> 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

<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res/com.example.bt"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:gravity="top"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.bt.MainActivity$PlaceholderFragment" >

    <LinearLayout
        android:id="@+id/linearLayout1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:orientation="vertical" >

        <TextView
            android:id="@+id/textView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Enter Text Here" />

        <EditText
            android:id="@+id/editText"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:ems="10" >

            <requestFocus />
        </EditText>
    </LinearLayout>

    <Button
        android:id="@+id/open"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/send"
        android:layout_alignBottom="@+id/send"
        android:layout_alignRight="@+id/linearLayout1"
        android:text="Open" />

    <Button
        android:id="@+id/send"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/linearLayout1"
        android:layout_marginTop="15dp"
        android:layout_toLeftOf="@+id/button1"
        android:text="Send" />

    <TextView
        android:id="@+id/recievedText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/send"
        android:layout_below="@+id/send"
        android:layout_marginTop="20dp"
        android:text="Received Text" />

    <TextView
        android:id="@+id/rtArea"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/recievedText"
        android:layout_alignParentBottom="true"
        android:layout_below="@+id/recievedText"
        android:layout_marginTop="20dp"
        android:text="Received Text Will be Displayed Here..." />

</RelativeLayout>

我的Manifest

<?xml version="1.0" encoding="utf-8"?>
<manifest
    xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.bt"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="19" />

    <supports-screens android:anyDensity="true" />

    <uses-permission android:name="android.permissions.BLUETOOTH" />
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>
    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.bt.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

所以我想知道：

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

感谢所有的帮助人员。

Answer 1

一步一步来。

setContentView(R.layout.activity_main);

将设置视图的内容，我假设您在Fragment_main中定义的视图应为fragment_main作为其XML文件。 因此，如果将其更改为

setContentView(R.layout. fragment_main);

您应该能够看到用户界面。