在Android中如何侦听Service内部的状态

第一步，在MainActivity中：

package com.example.yangjian.connectservice;

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.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;


public class MainActivity extends ActionBarActivity implements View.OnClickListener, ServiceConnection {

    private EditText etData;
    private MyService.Binder binder = null;
    private TextView tvOut;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        etData = (EditText) findViewById(R.id.etData);
        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 v) {
        switch (v.getId()) {
            case R.id.btnStartService:
                Intent i = new Intent(this, MyService.class);
                i.putExtra("data", etData.getText().toString());
                startService(i);
                break;

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

            case R.id.btnBindService:
                bindService(new Intent(this, MyService.class), this, Context.BIND_AUTO_CREATE);
                break;

            case R.id.btnUnbindService:
                unbindService(this);
                break;

            case R.id.btnSyncData:
                if (binder != null) {
                    binder.setData(etData.getText().toString());
                }
                break;
        }
    }

    @Override
    public void onServiceConnected(ComponentName name, IBinder service) {
        binder = (MyService.Binder)service;
        binder.getService().setCallback(new MyService.Callback() {
            @Override
            public void onDataChange(String data) {
                Message msg = new Message();
                Bundle b = new Bundle();
                b.putString("data", data);
                msg.setData(b);
                handler.sendMessage(msg);
            }
        });
    }

    @Override
    public void onServiceDisconnected(ComponentName name) {

    }

    private android.os.Handler handler = new android.os.Handler(){
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);

            tvOut.setText(msg.getData().getString("data"));
        }
    };


}

第二步，在MyService中：

package com.example.yangjian.connectservice;

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

public class MyService extends Service {
    private boolean running = false;
    private String data = "information";

    public MyService() {
    }

    @Override
    public IBinder onBind(Intent intent) {
        return new Binder();
    }

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

        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();

        running = true;

        new Thread(){
            @Override
            public void run() {
                super.run();
                int i=0;
                while (running) {
                    i++;

                    String str = i+":"+data;
                    System.out.println(str);  //指明是第几次执行

                    if (callback != null) {
                        callback.onDataChange(str);
                    }
                    
                    try {
                        sleep(1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }

                }
            }
        }.start();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();

        running = false;
    }

    private Callback callback = null;

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

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

    public Callback getCallback() {
        return callback;
    }
}

在MainXml中：

<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:paddingBottom="@dimen/activity_vertical_margin"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:id="@+id/tvOut"/>

    <EditText
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="默认信息"
        android:id="@+id/etData"/>

    <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"/>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="绑定服务"
        android:id="@+id/btnBindService" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="解除绑定服务"
        android:id="@+id/btnUnbindService" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="同步数据"
        android:id="@+id/btnSyncData" />

</LinearLayout>