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内容：详细讲解service
一、模拟后台下载（所有后台运行情况都相似）
二、service刷新活动UI
三、service和活动间的通信（）
四、service和活动生命周期关系
一、模拟后台下载（所有后台运行情况都相似）
二、service刷新活动UI
步骤：
1、新建两个活动，在第二个活动处开启service
2、service中启动下载，并不停发送广播
3、第二个活动重写 BroadcastReceiver 不停接收广播信息，并将接收的信息传递给活动进行UI更新
4、注册活动和service
代码如下：
package com.example.leixiansheng.servicetest2;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button = (Button) findViewById(R.id.btn);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(MainActivity.this,SecondActivity.class);
startActivity(intent);
}
});
}
@Override
protected void onDestroy() {
super.onDestroy();
Intent intent = new Intent(this,TestService.class);
// bindService() 和活动关联，活动终止，绑定必须在次活动前解绑，否则报错
// startService() 与活动无关联，自行运行。（任何活动都可以终止service）
//退出程序也没有stopService ，service 依旧在运行
//停止service
stopService(intent);
}
}
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.example.leixiansheng.servicetest2.MainActivity">
<TextView
android:text="这是活动一"
android:textSize="20dp"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<Button
android:id="@+id/btn"
android:text="Go to SecondActivity"
android:textAllCaps="false"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
package com.example.leixiansheng.servicetest2;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
/**
* Created by Leixiansheng on 2017/4/25.
*/
public class SecondActivity extends AppCompatActivity {
private Person person;
private Intent intent;
private TextView textView;
private int num;
private final static String MYACTION = "com.leixiansheng.broadcast";
//刷新UI
Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
textView.setText("下载进度：" + num + "%");
}
};
/**
* person对象无用，
* 只是为了测试开启service后
* 再次进入时对象是否相同（测试结果：不同）
* @param savedInstanceState
*/
@Override
protected void onCreate( Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.second_layout);
//模拟（每次重新进入对象都不同）
person = new Person();
Log.i("SecondActivity",String.valueOf(person));
textView = (TextView) findViewById(R.id.text_view);
Button button = (Button) findViewById(R.id.start);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
intent = new Intent(SecondActivity.this,TestService.class);
startService(intent);
person.setContext(SecondActivity.this);
person.getAll();
}
});
}
//接收广播传递的数据
BroadcastReceiver receiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context,Intent intent) {
//判断是否是所需广播
if (MYACTION.equals(intent.getAction())) {
num = intent.getIntExtra("CurrentLoading",0);
Log.e("SecondActivity","get the broadcast from TestService..."+ num);
//发送消息，提醒handler刷新UI
handler.sendMessage(handler.obtainMessage());
}
}
};
//动态注册广播（也可以继承广播，以静态方式注册）
@Override
protected void onResume() {
super.onResume();
IntentFilter filter = new IntentFilter();
filter.addAction(MYACTION);
registerReceiver(receiver,filter);
}
//销毁时必须解绑
@Override
protected void onDestroy() {
super.onDestroy();
Log.i("MyBroadcastReceiver","unregister the broadcast receiver...");
unregisterReceiver(receiver);
// stopService(intent);
}
}
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="@+id/text_view"
android:text="等待下载"
android:textSize="20dp"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<Button
android:id="@+id/start"
android:text="开始后台下载"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<TextView
android:text="这是活动二"
android:textSize="20dp"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>package com.example.leixiansheng.servicetest2;
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.util.Log;
import java.util.Timer;
import java.util.TimerTask;
/**
* Created by Leixiansheng on 2017/4/25.
*/
public class TestService extends Service {
private Person person;
private int i;
private Intent intent;
private Timer timer;
@Override
public IBinder onBind(Intent intent) {
return null;
}
@Override
public void onCreate() {
super.onCreate();
person = new Person();
Log.i("TestService",String.valueOf(person));
intent = new Intent("com.leixiansheng.broadcast");
//模拟开启后台下载
timer = new Timer();
timer.schedule(new MyTimerTask(),500);
}
private class MyTimerTask extends TimerTask {
@Override
public void run() {
if (i == 100) {
i = 0;
}
//携带数据，发送广播
intent.putExtra("CurrentLoading",i);
sendBroadcast(intent);
i++;
Log.e("TestService","i=" + i);
}
}
//活动结束，销毁timer
@Override
public void onDestroy() {
super.onDestroy();
timer.cancel();
}
}
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.leixiansheng.servicetest2">
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".SecondActivity" />
<service android:name=".TestService" />
</application>
</manifest>
三、service和活动间的通信
四、service和活动生命周期关系
代码如下：
package com.example.leixiansheng.test;
import android.content.ComponentName;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.IBinder;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
public class MainActivity extends AppCompatActivity {
private final static String TAG = "MainActivity";
private Intent intent;
private MyService.DownloadBinder downloadBinder;
//此处与service进行通信
private ServiceConnection connection = new ServiceConnection() {
@Override
public void onServiceConnected(ComponentName componentName,IBinder iBinder) {
downloadBinder = (MyService.DownloadBinder) iBinder;
downloadBinder.progress();
}
@Override
public void onServiceDisconnected(ComponentName componentName) {
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
intent = new Intent(this,MyService.class);
startService(intent);
bindService(intent,connection,BIND_AUTO_CREATE);
Log.i(TAG,"onCreate");
}
@Override
protected void onStart() {
super.onStart();
Log.i(TAG,"onStart");
}
@Override
protected void onResume() {
super.onResume();
Log.i(TAG,"onResume");
}
@Override
protected void onPause() {
super.onPause();
Log.i(TAG,"onPause");
}
@Override
protected void onStop() {
super.onStop();
Log.i(TAG,"onStop");
}
//必须解绑
@Override
protected void onDestroy() {
super.onDestroy();
Log.i(TAG,"onDestroy");
unbindService(connection);
stopService(intent);
}
}
package com.example.leixiansheng.test;
import android.app.DownloadManager;
import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;
import android.util.Log;
/**
* Created by Leixiansheng on 2017/5/2.
*/
public class MyService extends Service {
private final static String TAG = "MyService";
private DownloadBinder downloadBinder = new DownloadBinder();
public class DownloadBinder extends Binder {
public void progress() {
Log.i(TAG,"progress");
}
}
@Override
public IBinder onBind(Intent intent) {
Log.i(TAG,"onBind");
return downloadBinder;
}
@Override
public void onCreate() {
super.onCreate();
Log.i(TAG,"onCreate");
}
@Override
public int onStartCommand(Intent intent,int flags,int startId) {
Log.i(TAG,"onStartCommand");
return super.onStartCommand(intent,flags,startId);
}
@Override
public void onDestroy() {
super.onDestroy();
Log.i(TAG,"onDestroy");
}
}
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.leixiansheng.test">
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<service android:name=".MyService"/>
</application>
</manifest>
运行顺序：
05-03 10:22:07.805 16119-16119/com.example.leixiansheng.test I/MainActivity: onCreate
05-03 10:22:07.805 16119-16119/com.example.leixiansheng.test I/MainActivity: onStart
05-03 10:22:07.805 16119-16119/com.example.leixiansheng.test I/MainActivity: onResume
05-03 10:22:07.835 16119-16119/com.example.leixiansheng.test I/MyService: onCreate
05-03 10:22:07.835 16119-16119/com.example.leixiansheng.test I/MyService: onStartCommand
05-03 10:22:07.835 16119-16119/com.example.leixiansheng.test I/MyService: onBind
05-03 10:22:07.915 16119-16119/com.example.leixiansheng.test I/MyService: progress
05-03 10:22:47.615 16119-16119/com.example.leixiansheng.test I/MainActivity: onPause
05-03 10:22:47.945 16119-16119/com.example.leixiansheng.test I/MainActivity: onStop
05-03 10:22:47.945 16119-16119/com.example.leixiansheng.test I/MainActivity: onDestroy
05-03 10:22:47.955 16119-16119/com.example.leixiansheng.test I/MyService: onDestroy
小结：
1、bindService() 和活动关联，活动终止，绑定必须在次活动前解绑，否则报错
startService() 与活动无关联，自行运行。（任何活动都可以终止service），退出程序也没有stopService ，service 依旧在运行
2、服务 onCreate 只执行一次，后面再startService 只执行onStartCommand
3、server本身就继承了活动的context
4、活动和服务的生命周期关系是，先开启活动，再执行服务，先销毁活动，再销毁服务
5、····待补充
