androi之Service+Broadcast+Timer+ui【通过绑定服务、自定义回调接口判断网络连接】

最近项目要定时从服务器获取某些信息，通过研究来总结一下下【我以定时判断网络状态为例来阐述】

原理：

我们定义一个Service，在该Service中设置一个定时器Timer,通过TimerTask的策略来检查当前应用的网络连接状态，关键是在该Service需要自定义一个回调接口用于向我们的Activity来回调发送网络状态，然后通过Bind来绑定当前的Service,在绑定成功之后得到回调信息

代码：

Service类

package com.example.androidtimerdemo;

import java.util.Timer;
import java.util.TimerTask;

import android.app.Service;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.net.NetworkInfo.State;
import android.os.Binder;
import android.os.IBinder;
import android.util.Log;
import android.widget.Toast;

public class NetService extends Service
{

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

//上下文
Context context;

//网络连接状态
boolean isConntect = true;

//定时器
Timer timer = new Timer();

@Override
public void onCreate()
{
// 注册广播   检查网络状态
IntentFilter filter = new IntentFilter();
filter.addAction( ConnectivityManager.CONNECTIVITY_ACTION );
registerReceiver( receiver, filter );
Log.i( "tag", "service**"+Thread.currentThread().getId() );
super.onCreate();
}

//网络检查广播接受者
private BroadcastReceiver receiver = new BroadcastReceiver()
{

@Override
public void onReceive(Context context, Intent intent)
{
String action = intent.getAction();
// 启动定时任务
if (action.equals( ConnectivityManager.CONNECTIVITY_ACTION ))
{
//立即启动，每隔5秒执行一次Task
Log.i( "tag", "receiver**"+Thread.currentThread().getId() );
timer.schedule( new NetTask( context ), 0, 5*1000 );
}
}
};

//具体的TimerTask实现类
class NetTask extends TimerTask
{

public NetTask(Context context1)
{
context = context1;
}

@Override
public void run()
{

try
{
Thread.sleep( 20*1000 );
}
catch (InterruptedException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}

if (isConnectNet())
{
isConntect = true;
}
else
{
isConntect = false;
}
Log.i( "tag", "run**"+Thread.currentThread().getId() );
if (onGetConnectState != null)
{
onGetConnectState.GetState( isConntect ); // 通知网络状态改变
}
}

}

// 网络状态改变之后，通过此接口的实例通知当前网络的状态，此接口在Activity中注入实例对象
public interface GetConnectState
{
public void GetState(boolean isConnected);
}

private GetConnectState onGetConnectState;

public void setOnGetConnectState(GetConnectState onGetConnectState)
{
this.onGetConnectState = onGetConnectState;
}

/**
* 判断是否连通网络
* @return
*/
private boolean isConnectNet()
{
ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService( Context.CONNECTIVITY_SERVICE );
NetworkInfo Mobile = connectivityManager.getNetworkInfo( ConnectivityManager.TYPE_MOBILE );

NetworkInfo Wifi = connectivityManager.getNetworkInfo( ConnectivityManager.TYPE_WIFI );
if (Mobile.getState().equals( State.DISCONNECTED ) && Wifi.getState().equals( State.DISCONNECTED ))
{
return false;
}
return true;
}

//定义一个Bind类
private NetBind netBind = new NetBind();
class NetBind extends Binder
{
public NetService getNetService()
{
return NetService.this;
}
}

//销毁广播、停止定时轮询
@Override
public void onDestroy()
{
// TODO Auto-generated method stub
super.onDestroy();
timer.cancel();
unregisterReceiver( receiver );
}

}

Activity:

package com.example.androidtimerdemo;

import java.util.Timer;
import java.util.TimerTask;

import com.example.androidtimerdemo.MybindService.MyBind;
import com.example.androidtimerdemo.NetService.GetConnectState;
import com.example.androidtimerdemo.NetService.NetBind;

import android.os.Bundle;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.app.Activity;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity implements OnClickListener
{

TextView textView;

TextView textView2;

Button button1, button2;

Activity activity;

@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate( savedInstanceState );
setContentView( R.layout.activity_main );
activity = this;
initView();
}

private void initView()
{
textView = (TextView) findViewById( R.id.textView1 );
textView2 = (TextView) findViewById( R.id.textView2 );
button1 = (Button) findViewById( R.id.button1 );
button2 = (Button) findViewById( R.id.button2 );
button1.setOnClickListener( this );
button2.setOnClickListener( this );

}

boolean is;

@Override
public void onClick(View v)
{
switch (v.getId())
{
case R.id.button1:
// 绑定服务
Log.i( "tag", "click**" + Thread.currentThread().getId() );
Intent intent = new Intent( activity, NetService.class );
boolean isTrue = bindService( intent, conn, Context.BIND_AUTO_CREATE );
is = isTrue;
break;
case R.id.button2:
unBind();
default:
break;
}
}

private void unBind()
{
if (conn != null)
{
unbindService( conn );
}
}

private boolean conncetState = true;

private ServiceConnection conn = new ServiceConnection()
{

@Override
public void onServiceDisconnected(ComponentName name)
{
// TODO Auto-generated method stub

}

@Override
public void onServiceConnected(ComponentName name, IBinder service)
{

NetBind bind = (NetBind) service;
NetService netService = bind.getNetService();
//此处回调
netService.setOnGetConnectState( new GetConnectState()
{

@Override
public void GetState(boolean isConnected)
{
// TODO Auto-generated method stub
if (conncetState != isConnected)
{
conncetState = isConnected;
}
Message msg = handler.obtainMessage();
if (conncetState)
{
msg.what = 1;
}
else
{
msg.what = 2;
}
handler.sendMessage( msg );
}
} );

}
};

Handler handler = new Handler()
{
public void handleMessage(Message msg)
{
switch (msg.what)
{
case 1:
Toast.makeText( activity, "connect", 2000 ).show();
break;
case 2:
Toast.makeText( activity, "not", 2000 ).show();
default:
break;
}
};
};

}

PS：记得加网络权限哦