（六）Android中Service通信

一、启动Service并传递参数

传递参数时只需在startService启动的Intent中传入数据便可，接收参数时可在onStartCommand函数中通过读取第一个参数Intent的内容来实现

1.MainActivity.java

package com.example.shiyanshi.serviceconnected;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;

public class MainActivity extends Activity implements View.OnClickListener {
    private EditText editText;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        editText= (EditText) findViewById(R.id.editText);
        findViewById(R.id.btnStartService).setOnClickListener(this);
        findViewById(R.id.btnStopService).setOnClickListener(this);
    }

      @Override
    public void onClick(View view) {
        switch (view.getId()){
            case R.id.btnStartService:                

Intent intent=new Intent(MainActivity.this,MyService.class);
intent.putExtra("data",editText.getText().toString());
startService(intent);

                break;
            case R.id.btnStopService:
                stopService(new Intent(MainActivity.this,MyService.class));
        }

    }
}

2.MyService.java

package com.example.shiyanshi.serviceconnected;

import android.app.Service;
import android.content.Intent;
import android.os.IBinder;

public class MyService extends Service {
    private String data;
    private boolean flag;

    public MyService() {
    }

    @Override
    public IBinder onBind(Intent intent) {
        // TODO: Return the communication channel to the service.
        throw new UnsupportedOperationException("Not yet implemented");
    }

    @Override
    public int 

onStartCommand

(Intent intent, int flags, int startId) {

data=intent.getStringExtra("data");

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

    @Override
    public void onCreate() {
        super.onCreate();
        flag=true;
        new Thread() {
            @Override
            public void run() {
                super.run();
                while (flag) {
                    System.out.println(data);
                    try {
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        }.start();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        flag=false;
    }
}

3.布局文件

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

    <EditText android:text="@string/hello_world" android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:id="@+id/editText"/>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="启动服务"
        android:id="@+id/btnStartService" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="停止服务"
        android:id="@+id/btnStopService" />

</LinearLayout>

二、绑定Service进行通信

（1）Activity向Service传递消息

绑定服务后，Activity和Service之间可以通过android.os.Binder进行通信，当绑定服务时首先调用onCreate函数，然后调用Service类的onBind函数返回一个Binder，之后会调用Activity类中实现的onServiceConnected函数，该函数的第二个参数IBinder iBinder是Service类中onBind方法的返回值，通过这个Binder二者便可以成功通信。

1.MainActivity.java

package com.example.shiyanshi.serviceconnected;

import android.app.Activity;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;

public class MainActivity extends Activity implements View.OnClickListener, ServiceConnection {
    private EditText editText;
    private MyService.Binder binder=null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        editText= (EditText) findViewById(R.id.editText);
        findViewById(R.id.btnStartService).setOnClickListener(this);
        findViewById(R.id.btnStopService).setOnClickListener(this);        

findViewById(R.id.btnBindService).setOnClickListener(this);
findViewById(R.id.btnUnbindService).setOnClickListener(this);
findViewById(R.id.btnSyncData).setOnClickListener(this);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @Override
    public void onClick(View view) {
        switch (view.getId()){
            case R.id.btnStartService:
                Intent intent=new Intent(MainActivity.this,MyService.class);
                intent.putExtra("data",editText.getText().toString());
                startService(intent);
                break;
            case R.id.btnStopService:
                stopService(new Intent(MainActivity.this, MyService.class));
                break;           

case R.id.btnBindService:
bindService(new Intent(MainActivity.this, MyService.class), this, Context.BIND_AUTO_CREATE);
break;
case R.id.btnUnbindService:
unbindService(this);
break;
case R.id.btnSyncData:
if(binder!=null){
System.out.println("bind in not null");
binder.setData(editText.getText().toString()); //调用Bind中实现的数据交互方法
}
break;

        }

    }

    @Override
    public void onServiceConnected(ComponentName componentName, IBinder iBinder) {
        System.out.println("*****Connected Successful*******");       

binder= (MyService.Binder) iBinder;

    }

    @Override
    public void onServiceDisconnected(ComponentName componentName) {
        System.out.println("*****Disconnected Successful*******");

    }
}

2.MyService.java

package com.example.shiyanshi.serviceconnected;

import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;

public class MyService extends Service {
    private String data="default info";
    private boolean flag;

    public MyService() {
    }

    @Override
    public IBinder onBind(Intent intent) {
        // TODO: Return the communication channel to the service.
//        throw new UnsupportedOperationException("Not yet implemented");       

return new Binder(); //返回值会传给onServiceConnected函数的第二个参数IBinder

    }   

    //该类是Activity和Service进行交互数据的接口

public class Binder extends android.os.Binder{
public void setData(String data) {
MyService.this.data=data;
}

    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {

        data=intent.getStringExtra("data");
        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public void onCreate() {
        super.onCreate();
        System.out.println("*******onCreate********");
        flag=true;
        new Thread() {
            @Override
            public void run() {
                super.run();
                while (flag) {
                    System.out.println(data);
                    try {
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        }.start();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        System.out.println("******onDestroy******");
        flag=false;
    }
}

（2）Service向Activity传递消息，并将传递的数据显示到Activity中

主要通过在Service中设定一个回调函数的接口，并定义一个该接口的引用，该引用的实例化是在Activity中进行的，实例化的同时会重写该接口中定义的回调函数，让该回调函数发送一个消息，并且在消息处理器（Handler）中进行更新UI线程的内容；此外在新开的Thread线程中调用该回调函数进行更新数据。

1.MainActivity.java

package com.example.shiyanshi.serviceconnected;

import android.app.Activity;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.os.Message;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;

import org.w3c.dom.Text;

import java.util.logging.Handler;

public class MainActivity extends Activity implements View.OnClickListener, ServiceConnection {
    private EditText editText;
    private MyService.Binder binder=null;
    private TextView tvOut;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        editText= (EditText) findViewById(R.id.editText);
        tvOut=(TextView)findViewById(R.id.tvOut);

        findViewById(R.id.btnStartService).setOnClickListener(this);
        findViewById(R.id.btnStopService).setOnClickListener(this);
        findViewById(R.id.btnBindService).setOnClickListener(this);
        findViewById(R.id.btnUnbindService).setOnClickListener(this);
        findViewById(R.id.btnSyncData).setOnClickListener(this);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @Override
    public void onClick(View view) {
        switch (view.getId()){
            case R.id.btnStartService:
                Intent intent=new Intent(MainActivity.this,MyService.class);
                intent.putExtra("data",editText.getText().toString());
                startService(intent);
                break;
            case R.id.btnStopService:
                stopService(new Intent(MainActivity.this, MyService.class));
                break;
            case R.id.btnBindService:
                bindService(new Intent(MainActivity.this, MyService.class), this, Context.BIND_AUTO_CREATE);
                break;
            case R.id.btnUnbindService:
                unbindService(this);
                break;
            case R.id.btnSyncData:
                if(binder!=null){
                    System.out.println("bind in not null");
                    binder.setData(editText.getText().toString());
                }
                break;
        }

    }

    @Override
    public void onServiceConnected(ComponentName componentName, IBinder iBinder) {
        System.out.println("*****Connected Successful*******");
        binder= (MyService.Binder) iBinder;

//设置回调函数，在回调函数中通过发送消息和消息处理器进行修改UI线程要显示的内容
binder.getService().setCallback(new MyService.Callback() {
@Override
public void onDataChange(String data) {
//tvOut.setText(data); 这里不可以直接设置，因为由新创建的线程去调用这个函数，不允许直接修改UI线程的内容
Message msg=new Message();
Bundle bundle=new Bundle();
bundle.putString("data",data);
msg.setData(bundle);
handler.sendMessage(msg); //通过handler发送消息
}
});

    }

    @Override
    public void onServiceDisconnected(ComponentName componentName) {
        System.out.println("*****Disconnected Successful*******");

    }

//消息处理函数，接收Message并进行处理

private android.os.Handler handler=new android.os.Handler(){
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
tvOut.setText(msg.getData().getString("data"));

}
};

}

2.MyService.java

package com.example.shiyanshi.serviceconnected;

import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;

public class MyService extends Service {
    private String data="default info";
    private boolean flag;

    public MyService() {
    }

    @Override
    public IBinder onBind(Intent intent) {
        // TODO: Return the communication channel to the service.
//        throw new UnsupportedOperationException("Not yet implemented");
        System.out.println("******onBind*****");
        return new Binder();      //返回值会传给onServiceConnected函数的第二个参数IBinder
    }
    //该类是Activity和Service进行交互数据的接口
    public class Binder extends android.os.Binder{
        public void setData(String data) {
            MyService.this.data=data;
        }

//获取当前的MyService类的引用
public MyService getService(){
return MyService.this;
}

    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {

        data=intent.getStringExtra("data");
        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public void onCreate() {
        super.onCreate();
        System.out.println("*******onCreate********");
        flag=true;

        new Thread() {
            @Override
            public void run() {
                super.run();
                int i=0;
                while (flag) {
                    i++;
                    String str=i+":"+data;
                    System.out.println(str);

//由新创建的线程去调用这个函数，不允许直接修改UI线程的内容
if (callback!=null){
callback.onDataChange(str);
}

                    try {
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        }.start();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        System.out.println("******onDestroy******");
        flag=false;
    }

//创建的接口用于回调，回调函数（onDataChange）具体是在Activity中实现的

private Callback callback=null;

public void setCallback(Callback callback) {
this.callback = callback;
}

public Callback getCallback() {
return callback;
}

public static interface Callback{
void onDataChange(String data);
}

}