Android開發中編寫藍牙相關功能的核心代碼講解

一. 什麼是藍牙(Bluetooth)?
1.1  BuleTooth是目前使用最廣泛的無線通信協議
1.2  主要針對短距離設備通訊(10m)
1.3  常用於連接耳機，鼠標和移動通訊設備等.
二. 與藍牙相關的API
2.1 BluetoothAdapter:
代表了本地的藍牙適配器
2.2 BluetoothDevice
代表了一個遠程的Bluetooth設備
三. 掃描已經配對的藍牙設備(1)
注：必須部署在真實手機上，模擬器無法實現
首先需要在AndroidManifest.xml 聲明藍牙權限
<user-permission android:name="android.permission.BLUETOOTH" />
配對藍牙需要手動操作:
1. 打開設置--> 無線網絡 --> 藍牙 勾選開啟
2. 打開藍牙設置  掃描周圍已經開啟的藍牙設備(可以與自己的筆記本電腦進行配對)，點擊進行配對
 電腦上會彈出提示窗口: 添加設備
 顯示計算與設備之間的配對碼，要求確認是否配對
 手機上也會顯示類似的提示.
四. 掃描已經配對的藍牙設備(2)
4.1 獲得BluetoothAdapter對象
4.2 判斷當前移動設備中是否擁有藍牙
4.3 判斷當前移動設備中藍牙是否已經打開
4.4 得到所有已經配對的藍牙設備對象

藍牙配對實現的核心代碼如下:

MainActivity:

import java.util.Iterator; 
import java.util.Set; 
 
import android.app.Activity; 
import android.bluetooth.BluetoothAdapter; 
import android.bluetooth.BluetoothDevice; 
import android.content.Intent; 
import android.os.Bundle; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 
 
public class MainActivity extends Activity { 
  private Button button = null; 
  /** Called when the activity is first created. */ 
  @Override 
  public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 
     
    button = (Button)findViewById(R.id.buttonId); 
    button.setOnClickListener(new OnClickListener(){ 
 
      @Override 
      public void onClick(View v) { 
        //獲得BluetoothAdapter對象，該API是android 2.0開始支持的 
        BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter(); 
        //adapter不等於null，說明本機有藍牙設備 
        if(adapter != null){ 
          System.out.println("本機有藍牙設備！"); 
          //如果藍牙設備未開啟 
          if(!adapter.isEnabled()){ 
            Intent intent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE); 
            //請求開啟藍牙設備 
            startActivity(intent); 
          } 
          //獲得已配對的遠程藍牙設備的集合 
          Set<BluetoothDevice> devices = adapter.getBondedDevices(); 
          if(devices.size()>0){ 
            for(Iterator<BluetoothDevice> it = devices.iterator();it.hasNext();){ 
              BluetoothDevice device = (BluetoothDevice)it.next(); 
              //打印出遠程藍牙設備的物理地址 
              System.out.println(device.getAddress()); 
            } 
          }else{ 
            System.out.println("還沒有已配對的遠程藍牙設備！"); 
          } 
        }else{ 
          System.out.println("本機沒有藍牙設備！"); 
        } 
      } 
    }); 
  } 
} 

修改本機藍牙設備的可見性,並掃描周圍可用的藍牙設備
1. 修改本機藍牙設備的可見性
2. 掃描周圍可用的藍牙設備

Eg:
一.  清單文件AdroidManifest.xml:

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
   package="com.se7en" 
   android:versionCode="1" 
   android:versionName="1.0"> 
  <uses-sdk android:minSdkVersion="8" /> 
 
  <application android:icon="@drawable/icon" android:label="@string/app_name"> 
    <activity android:name=".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> 
  <uses-permission android:name="android.permission.BLUETOOTH"/> 
   
  <!-若需要管理藍牙設備，如修改可見性，則需以下的權限-> 
  <uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/> 
</manifest> 

二. 布局文件: main.xml:

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
  android:orientation="vertical" 
  android:layout_width="fill_parent" 
  android:layout_height="fill_parent" 
  > 
  <TextView  
    android:layout_width="fill_parent"  
    android:layout_height="wrap_content"  
    android:text="@string/hello" 
    /> 
  <Button  
    android:id="@+id/discoverButton" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="設置可見性"/> 
  <Button  
    android:id="@+id/scanButton" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="開始掃描"/> 
</LinearLayout> 

三. MainActivity:

import android.app.Activity; 
import android.bluetooth.BluetoothAdapter; 
import android.bluetooth.BluetoothDevice; 
import android.content.BroadcastReceiver; 
import android.content.Context; 
import android.content.Intent; 
import android.content.IntentFilter; 
import android.os.Bundle; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 
 
public class MainActivity extends Activity { 
  private Button discoverButton = null; 
  private Button scanButton = null; 
  private BluetoothAdapter adapter = null; 
  private BluetoothReceiver bluetoothReceiver = null; 
  /** Called when the activity is first created. */ 
  @Override 
  public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 
     
    adapter = BluetoothAdapter.getDefaultAdapter(); 
     
    discoverButton = (Button)findViewById(R.id.discoverButton); 
    scanButton = (Button)findViewById(R.id.scanButton); 
    //修改藍牙設備的可見性 
    discoverButton.setOnClickListener(new OnClickListener(){ 
      @Override 
      public void onClick(View view) { 
      Intent discoverIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE); 
 
//設置藍牙可見性，500表示可見時間（單位：秒），當值大於300時默認為300 
discoverIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION,500); 
startActivity(discoverIntent); 
      } 
    }); 
     
    scanButton.setOnClickListener(new OnClickListener(){ 
      @Override 
      public void onClick(View v) { 
    //開始掃描周圍藍牙設備，該方法是異步調用並以廣播的機制返回，所以需要創建一個BroadcastReceiver來獲取信息 
        adapter.startDiscovery(); 
      } 
    }); 
     
    //設定廣播接收的filter 
    IntentFilter intentFilter = new IntentFilter(BluetoothDevice.ACTION_FOUND); 
    //創建藍牙廣播信息的receiver 
    bluetoothReceiver = new BluetoothReceiver (); 
    //注冊廣播接收器 
    registerReceiver(bluetoothReceiver,intentFilter); 
       
  } 
   
  private class BluetoothReceiver extends BroadcastReceiver{ 
    @Override 
    public void onReceive(Context context, Intent intent) { 
      //獲得掃描到的遠程藍牙設備 
      BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE); 
      System.out.println(device.getAddress()); 
    } 
     
  } 
}