Android Service和Activity基于串口蓝牙模块的双向通信【第二篇】

一直以来都想利用手机来控制一些东西,比如电灯,电风扇等家电或者智能小车等.

驱动蓝牙模块可以在Activity中直接调用,也可以在多线程下直接使用,但这样会存在一个缺陷:当你按下手机的Home或者Back键的时候.程序退出了,下次你重新启动软件的时候又需要重新建立蓝牙的链接了.

为了克服以上问题,我把蓝牙模块的调用放到Service里面使用.首先对Service说明下:(来源于http://tianrui-wang-163-com.iteye.com/blog/983099)

Service介绍

Android中的服务和windows中的服务是类似的东西，服务一般没有用户操作界面，它运行于系统中不容易被用户发觉，可以使用它开发如监控之类的程序。

由于没有可视化界面，Service都是从其它程序组件中启动、停止和控制，这些组件包括其它的Service、Activity和Broadcast Receiver。如果你的应用程序正常且不间断的运行，而不直接依赖于用户输入，Service是你最佳的选择。

Service生命周期

服务常用生命周期回调方法如下：

onCreate() 该方法在服务被创建时调用，该方法只会被调用一次，无论调用多少次startService()或bindService()方法，服务也只被创建一次。

onDestroy()该方法在服务被终止时调用。

Service对象不能自己启动，需要通过某个Activity、Service或者其他Context对象来启动。启动的方法有两种，Context.startService和Context.bindService()。两种方式的生命周期是不同的，具体如下所示。

Context.startService方式的生命周期：

启动时，startService –> onCreate() –> onStart()

停止时，stopService –> onDestroy()

Context.bindService方式的生命周期：

绑定时,bindService -> onCreate() –> onBind()

解绑定时,unbindService –>onUnbind() –> onDestory()

Service实现

定义一个Service只需要如下两步：

第一步：继承Service类

public class SMSService extends Service { } 这里可以选择要实现的方法

第二步：在AndroidManifest.xml文件中的<application>节点里对服务进行配置:

<service android:name=".SMSService" ”></service>



好了,废话少说,下面从我的代码直接开始:

[java]
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package com.lxx;


import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.UUID;

import android.app.Service;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.IBinder;
import android.util.Log;


public class MyService extends Service{

public boolean threadFlag = true;
MyThread myThread;
CommandReceiver cmdReceiver;//继承自BroadcastReceiver对象，用于得到Activity发送过来的命令


/**************service 命令*********/
static final int CMD_STOP_SERVICE = 0x01;
static final int CMD_SEND_DATA = 0x02;
static final int CMD_SYSTEM_EXIT =0x03;
static final int CMD_SHOW_TOAST =0x04;

private BluetoothAdapter mBluetoothAdapter = null;
private BluetoothSocket btSocket = null;
private OutputStream outStream = null;
private InputStream inStream = null;
public boolean bluetoothFlag = true;
private static final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
private static String address = "00:19:5D:EE:9B:8F"; // <==要连接的蓝牙设备MAC地址


@Override
public IBinder onBind(Intent intent) {
// TODO Auto-generated method stub

return null;
}

@Override
public void onCreate() {
// TODO Auto-generated method stub

super.onCreate();

}



//前台Activity调用startService时，该方法自动执行

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
// TODO Auto-generated method stub

cmdReceiver = new CommandReceiver();
IntentFilter filter = new IntentFilter();//创建IntentFilter对象

//注册一个广播，用于接收Activity传送过来的命令，控制Service的行为，如：发送数据，停止服务等

filter.addAction("android.intent.action.cmd");
//注册Broadcast Receiver
registerReceiver(cmdReceiver, filter);
doJob();//调用方法启动线程
return super.onStartCommand(intent, flags, startId);

}



@Override
public void onDestroy() {
// TODO Auto-generated method stub

super.onDestroy();
this.unregisterReceiver(cmdReceiver);//取消注册的CommandReceiver

threadFlag = false;
boolean retry = true;
while(retry){
try{
myThread.join();
retry = false;
}catch(Exception e){
e.printStackTrace();
}

}
}

public class MyThread extends Thread{
@Override
public void run() {
// TODO Auto-generated method stub

super.run();
connectDevice();//连接蓝牙设备

while(threadFlag){
int value = readByte();
if(value != -1){
DisplayToast(value + "");
}

try{
Thread.sleep(50);
}catch(Exception e){
e.printStackTrace();
}
}
}
}

public void doJob(){
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (mBluetoothAdapter == null) {
DisplayToast("蓝牙设备不可用，请打开蓝牙！");
bluetoothFlag = false;
return;
}

if (!mBluetoothAdapter.isEnabled()) {
DisplayToast("请打开蓝牙并重新运行程序！");
bluetoothFlag = false;
stopService();
showToast("请打开蓝牙并重新运行程序！");
return;
}
showToast("搜索到蓝牙设备!");
threadFlag = true;
myThread = new MyThread();
myThread.start();

}
public void connectDevice(){
DisplayToast("正在尝试连接蓝牙设备，请稍后····");
BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(address);
try {
btSocket = device.createRfcommSocketToServiceRecord(MY_UUID);
} catch (IOException e) {
DisplayToast("套接字创建失败！");
bluetoothFlag = false;
}
DisplayToast("成功连接蓝牙设备！");
mBluetoothAdapter.cancelDiscovery();
try {
btSocket.connect();
DisplayToast("连接成功建立，可以开始操控了!");
showToast("连接成功建立，可以开始操控了!");
bluetoothFlag = true;
} catch (IOException e) {
try {
btSocket.close();
bluetoothFlag = false;
} catch (IOException e2) {
DisplayToast("连接没有建立，无法关闭套接字！");
}
}

if(bluetoothFlag){
try {
inStream = btSocket.getInputStream();
} catch (IOException e) {
e.printStackTrace();
} //绑定读接口


try {
outStream = btSocket.getOutputStream();
} catch (IOException e) {
e.printStackTrace();
} //绑定写接口


}
}

public void sendCmd(byte cmd, int value)//串口发送数据

{
if(!bluetoothFlag){
return;
}
byte[] msgBuffer = new byte[5];
msgBuffer[0] = cmd;
msgBuffer[1] = (byte)(value >> 0 & 0xff);
msgBuffer[2] = (byte)(value >> 8 & 0xff);
msgBuffer[3] = (byte)(value >> 16 & 0xff);
msgBuffer[4] = (byte)(value >> 24 & 0xff);

try {
outStream.write(msgBuffer, 0, 5);
outStream.flush();
} catch (IOException e) {
e.printStackTrace();
}
}

public int readByte(){//return -1 if no data

int ret = -1;
if(!bluetoothFlag){
return ret;
}
try {
ret = inStream.read();
} catch (IOException e) {
e.printStackTrace();
}
return ret;
}

public void stopService(){//停止服务

threadFlag = false;//停止线程

stopSelf();//停止服务

}

public void showToast(String str){//显示提示信息

Intent intent = new Intent();
intent.putExtra("cmd", CMD_SHOW_TOAST);
intent.putExtra("str", str);
intent.setAction("android.intent.action.lxx");
sendBroadcast(intent);
}

public void DisplayToast(String str)
{
Log.d("Season",str);
}

//接收Activity传送过来的命令

private class CommandReceiver extends BroadcastReceiver{
@Override
public void onReceive(Context context, Intent intent) {
if(intent.getAction().equals("android.intent.action.cmd")){
int cmd = intent.getIntExtra("cmd", -1);//获取Extra信息

if(cmd == CMD_STOP_SERVICE){
stopService();
}

if(cmd == CMD_SEND_DATA)
{
byte command = intent.getByteExtra("command", (byte) 0);
int value = intent.getIntExtra("value", 0);
sendCmd(command,value);
}

}
}
}



}

[java] 
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package com.lxx;  
  
import android.app.Activity;  
import android.content.BroadcastReceiver;  
import android.content.Context;  
import android.content.Intent;  
import android.content.IntentFilter;  
import android.os.Bundle;  
import android.os.IBinder;  
import android.view.View;  
import android.view.View.OnClickListener;  
import android.widget.Button;  
import android.widget.TextView;  
import android.widget.Toast;  
  
public class BroadcastActivity extends Activity {  
    /** Called when the activity is first created. */  
  
    TextView myTextView;  
    Button sendButton;  
    MyReceiver receiver;  
    IBinder serviceBinder;  
    MyService mService;  
    Intent intent;  
    int value = 0;  
      
    /**************service 命令*********/   
    static final int CMD_STOP_SERVICE = 0x01;  
    static final int CMD_SEND_DATA = 0x02;  
    static final int CMD_SYSTEM_EXIT =0x03;  
    static final int CMD_SHOW_TOAST =0x04;  
      
    @Override  
    public void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.main);  
          
        myTextView = (TextView)findViewById(R.id.myTextView);  
        myTextView.setText("Season");    
        sendButton = (Button)findViewById(R.id.sendButton);  
        sendButton.setOnClickListener(new SendButtonClickListener());  
                    
        intent = new Intent(BroadcastActivity.this,MyService.class);  
        startService(intent);  
    }  
      
    
    public class SendButtonClickListener implements OnClickListener{  
  
        @Override  
        public void onClick(View v) {  
            // TODO Auto-generated method stub
  
            byte command = 45;  
            int value = 0x12345;  
            sendCmd(command,value);  
        }     
    }  
      
    @Override  
    protected void onDestroy() {  
        // TODO Auto-generated method stub
  
        super.onDestroy();  
          
        if(receiver!=null){  
            BroadcastActivity.this.unregisterReceiver(receiver);  
        }  
    }  
  
     
  
  
    @Override  
    protected void onResume() {  
        // TODO Auto-generated method stub
  
        super.onResume();  
        receiver = new MyReceiver();  
        IntentFilter filter=new IntentFilter();  
        filter.addAction("android.intent.action.lxx");  
        BroadcastActivity.this.registerReceiver(receiver,filter);  
    }  
  
    public void showToast(String str){//显示提示信息
  
        Toast.makeText(getApplicationContext(), str, Toast.LENGTH_SHORT).show();      
    }  
  
  
    public class MyReceiver extends BroadcastReceiver{  
    @Override  
    public void onReceive(Context context, Intent intent) {  
        // TODO Auto-generated method stub
  
        if(intent.getAction().equals("android.intent.action.lxx")){  
            Bundle bundle = intent.getExtras();  
            int cmd = bundle.getInt("cmd");  
              
            if(cmd == CMD_SHOW_TOAST){  
                String str = bundle.getString("str");  
                showToast(str);  
            }  
              
            else if(cmd == CMD_SYSTEM_EXIT){  
                System.exit(0);  
            }  
              
        }  
     }     
   }  
  
    public void sendCmd(byte command, int value){  
        Intent intent = new Intent();//创建Intent对象
  
        intent.setAction("android.intent.action.cmd");  
        intent.putExtra("cmd", CMD_SEND_DATA);  
        intent.putExtra("command", command);  
        intent.putExtra("value", value);  
        sendBroadcast(intent);//发送广播     
  
    }  
      
   
}  

package com.lxx;

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.os.IBinder;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class BroadcastActivity extends Activity {
    /** Called when the activity is first created. */

	TextView myTextView;
	Button sendButton;
	MyReceiver receiver;
	IBinder serviceBinder;
	MyService mService;
	Intent intent;
	int value = 0;
	
	/**************service 命令*********/	
	static final int CMD_STOP_SERVICE = 0x01;
    static final int CMD_SEND_DATA = 0x02;
    static final int CMD_SYSTEM_EXIT =0x03;
    static final int CMD_SHOW_TOAST =0x04;
	
	@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        myTextView = (TextView)findViewById(R.id.myTextView);
        myTextView.setText("Season");  
        sendButton = (Button)findViewById(R.id.sendButton);
        sendButton.setOnClickListener(new SendButtonClickListener());
                  
        intent = new Intent(BroadcastActivity.this,MyService.class);
        startService(intent);
    }
    
  
    public class SendButtonClickListener implements OnClickListener{

		@Override
		public void onClick(View v) {
			// TODO Auto-generated method stub
			byte command = 45;
			int value = 0x12345;
            sendCmd(command,value);
		} 	
    }
    
    @Override
	protected void onDestroy() {
		// TODO Auto-generated method stub
		super.onDestroy();
		
		if(receiver!=null){
			BroadcastActivity.this.unregisterReceiver(receiver);
		}
	}

   

	@Override
	protected void onResume() {
		// TODO Auto-generated method stub
		super.onResume();
		receiver = new MyReceiver();
		IntentFilter filter=new IntentFilter();
		filter.addAction("android.intent.action.lxx");
		BroadcastActivity.this.registerReceiver(receiver,filter);
	}

    public void showToast(String str){//显示提示信息
    	Toast.makeText(getApplicationContext(), str, Toast.LENGTH_SHORT).show();	
    }

	public class MyReceiver extends BroadcastReceiver{
	@Override
	public void onReceive(Context context, Intent intent) {
		// TODO Auto-generated method stub
		if(intent.getAction().equals("android.intent.action.lxx")){
			Bundle bundle = intent.getExtras();
			int cmd = bundle.getInt("cmd");
			
			if(cmd == CMD_SHOW_TOAST){
				String str = bundle.getString("str");
			    showToast(str);
			}
			
			else if(cmd == CMD_SYSTEM_EXIT){
				System.exit(0);
			}
			
		}
	 }   
   }

	public void sendCmd(byte command, int value){
		Intent intent = new Intent();//创建Intent对象
        intent.setAction("android.intent.action.cmd");
        intent.putExtra("cmd", CMD_SEND_DATA);
        intent.putExtra("command", command);
        intent.putExtra("value", value);
        sendBroadcast(intent);//发送广播	
	}
	
 
}

以下主要对代码部分进行详细的说明:

1.为了方便Activity和Service简历起良好的通信关系,需要在各自发送的数据进行命令的解释,这些命令在两者之间是一致的,能够相互读懂对方发送过来的数据.

[java]
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/**************service 命令*********/
static final int CMD_STOP_SERVICE = 0x01;//停止服务

static final int CMD_SEND_DATA = 0x02;//发送数据

static final int CMD_SYSTEM_EXIT =0x03;//退出程序

static final int CMD_SHOW_TOAST =0x04;//界面上显示toast

[java] 
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//接收Activity传送过来的命令   
   private class CommandReceiver extends BroadcastReceiver{  
       @Override  
       public void onReceive(Context context, Intent intent) {  
        if(intent.getAction().equals("android.intent.action.cmd")){  
            int cmd = intent.getIntExtra("cmd", -1);//获取Extra信息                            
  
                 if(cmd == CMD_STOP_SERVICE){  
                  stopService();  
                 }    
                   
                 if(cmd == CMD_SEND_DATA)  
                 {  
                 byte command = intent.getByteExtra("command", (byte) 0);  
                 int value =  intent.getIntExtra("value", 0);  
                  sendCmd(command,value);  
                 }  
                          
        }     
       }                          
   }  

 //接收Activity传送过来的命令
    private class CommandReceiver extends BroadcastReceiver{
        @Override
        public void onReceive(Context context, Intent intent) {
        	if(intent.getAction().equals("android.intent.action.cmd")){
        		int cmd = intent.getIntExtra("cmd", -1);//获取Extra信息                            
                  if(cmd == CMD_STOP_SERVICE){
                	  stopService();
                  }  
                  
                  if(cmd == CMD_SEND_DATA)
                  {
                	 byte command = intent.getByteExtra("command", (byte) 0);
                	 int value =  intent.getIntExtra("value", 0);
                	  sendCmd(command,value);
                  }
                   		
        	}	
        }                        
    }

为了能够接收到数据,首先得把这个Receiver注册:

[java]
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public class MyReceiver extends BroadcastReceiver{
@Override
public void onReceive(Context context, Intent intent) {
// TODO Auto-generated method stub

if(intent.getAction().equals("android.intent.action.lxx")){
Bundle bundle = intent.getExtras();
int cmd = bundle.getInt("cmd");

if(cmd == CMD_SHOW_TOAST){
String str = bundle.getString("str");
showToast(str);
}

else if(cmd == CMD_SYSTEM_EXIT){
System.exit(0);
}

}
}
}

[java] 
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public class MyThread extends Thread{          
        @Override  
        public void run() {  
            // TODO Auto-generated method stub
  
            super.run();  
            connectDevice();//连接蓝牙设备 
  
         while(threadFlag){  
             int value = readByte();//从蓝牙模块读取一个字节的数据,解释命令用          
  
            if(value != -1){                  
                DisplayToast(value + "");         
            }  
              
            try{  
                Thread.sleep(50);  
            }catch(Exception e){  
                e.printStackTrace();  
            }              
         }  
       }      
    }  

public class MyThread extends Thread{        
		@Override
		public void run() {
			// TODO Auto-generated method stub
			super.run();
		    connectDevice();//连接蓝牙设备
		 while(threadFlag){
			 int value = readByte();//从蓝牙模块读取一个字节的数据,解释命令用			
			if(value != -1){				
				DisplayToast(value + "");		
			}
			
			try{
				Thread.sleep(50);
			}catch(Exception e){
				e.printStackTrace();
			}			 
		 }
	   }	
	}

3.Activity传送数据到Service:

Activity上有一个按钮,点击一下就可以发送数据到蓝牙串口模块,工作原理是这样的:界面上实现按钮的点击事件

[java]
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public class SendButtonClickListener implements OnClickListener{

@Override
public void onClick(View v) {
// TODO Auto-generated method stub

byte command = 45;
int value = 0x12345;
sendCmd(command,value);
}
}

[java] 
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public void sendCmd(byte command, int value){  
        Intent intent = new Intent();//创建Intent对象
  
        intent.setAction("android.intent.action.cmd");  
        intent.putExtra("cmd", CMD_SEND_DATA);  
        intent.putExtra("command", command);  
        intent.putExtra("value", value);  
        sendBroadcast(intent);//发送广播    
  
    }  

public void sendCmd(byte command, int value){
		Intent intent = new Intent();//创建Intent对象
        intent.setAction("android.intent.action.cmd");
        intent.putExtra("cmd", CMD_SEND_DATA);
        intent.putExtra("command", command);
        intent.putExtra("value", value);
        sendBroadcast(intent);//发送广播	
	}

Service中

[java]
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//前台Activity调用startService时，该方法自动执行

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
// TODO Auto-generated method stub

cmdReceiver = new CommandReceiver();
IntentFilter filter = new IntentFilter();//创建IntentFilter对象

//注册一个广播，用于接收Activity传送过来的命令，控制Service的行为，如：发送数据，停止服务等

filter.addAction("android.intent.action.cmd");
//注册Broadcast Receiver

registerReceiver(cmdReceiver, filter);
doJob();//调用方法启动线程

return super.onStartCommand(intent, flags, startId);

}

//前台Activity调用startService时，该方法自动执行
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
// TODO Auto-generated method stub
cmdReceiver = new CommandReceiver();
IntentFilter filter = new IntentFilter();//创建IntentFilter对象
//注册一个广播，用于接收Activity传送过来的命令，控制Service的行为，如：发送数据，停止服务等
filter.addAction("android.intent.action.cmd");
//注册Broadcast Receiver
registerReceiver(cmdReceiver, filter);
doJob();//调用方法启动线程
return super.onStartCommand(intent, flags, startId);

}
通过以上步骤就可以建立起蓝牙模块发送数据到Activity,Activity也可以发送数据到蓝牙模块了;

本例子的源码:

http://download.csdn.net/source/3557026

博文转自：http://blog.csdn.net/cen616899547/article/category/1133607