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Android专题8——本地服务和远程服务通信
关于远程服务
远程服务指的是服务和访问者不在同一个应用程序中,即不在同一个进程中。
访问远程服务类似进程间通信。
访问者和远程服务需要遵守能够被操作系统理解的协议,AIDL。
1. 在服务端和客户端配置AIDL
aidl文件最好都放在aidl目录下,aidl文件用于接口描述
会自动生成一个同名的JAVA文件
在自动生成的JAVA文件中,系统会自动定义一个Stub类,继承Binder类,实现aidl文件中描述的接口
2. 编写service业务代码
在清单文件中注册
实现自定义的IBinder
<service android:name=".StudentService"> <intent-filter > <action android:name="com.njulya.REMOTESERVICE"/> </intent-filter> </service>
import com.njulya.aidl.StudentQuery;import android.app.Service;import android.content.Intent;import android.os.IBinder;import android.os.RemoteException;public class StudentService extends Service { IBinder iBinder; String[] names = {"张阳","李永安","潘杰"}; @Override public IBinder onBind(Intent intent) { iBinder = new StudentBinder(); return iBinder; }/** * 实现IBinder接口,用于通信 * @author Andy */ private class StudentBinder extends StudentQuery.Stub{ @Override //aidl文件中描述的接口 public String query(int no) throws RemoteException { return names[no-1];//业务代码 } }}
3.编写客户端应用
package com.njulya.remoteserviceclient;import com.njulya.aidl.StudentQuery;import android.app.Activity;import android.content.ComponentName;import android.content.Intent;import android.content.ServiceConnection;import android.os.Bundle;import android.os.IBinder;import android.os.RemoteException;import android.view.Menu;import android.view.View;import android.widget.EditText;import android.widget.TextView;public class MainActivity extends Activity { private EditText studentId; private TextView content; private StudentQuery studentQuery; private ServiceConnection conn; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); studentId = (EditText)this.findViewById(R.id.student_id); content = (TextView)this.findViewById(R.id.content); conn = new StudentConnetion(); Intent service = new Intent("com.njulya.REMOTESERVICE"); this.bindService(service, conn, BIND_AUTO_CREATE); } /** * 按键触发业务代码 * @param v */ public void queryOnClick(View v){ int no = Integer.valueOf(studentId.getText().toString()); try { String studentName = studentQuery.query(no); content.setText(studentName); } catch (RemoteException e) { e.printStackTrace(); } } private class StudentConnetion implements ServiceConnection{ @Override public void onServiceConnected(ComponentName name, IBinder service) { //将IBinder代理对象转换为接口类型 studentQuery = StudentQuery.Stub.asInterface(service); } @Override public void onServiceDisconnected(ComponentName name) { studentQuery = null; } } @Override protected void onDestroy() { unbindService(conn); super.onDestroy(); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; } }
关于本地服务
启动的service是运行在主线程中的,所以耗时的操作还是要新建工作线程
用bindService时需要实现ServiceConnection,flags用BIND_AUTO_CREATE
service中关键要返回IBinder的实现类对象,该对象中会使用服务中的一些API
一般在自定义的ServiceConnection实现类中得到和关闭IBinder对象
通过得到的IBinder对象实现调用服务中的API
业务界面
客户端代码
package com.njulya.intsum;import android.os.Bundle;import android.os.IBinder;import android.app.Activity;import android.content.ComponentName;import android.content.Intent;import android.content.ServiceConnection;import android.view.Menu;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.EditText;import android.widget.TextView;public class MainActivity extends Activity { private EditText num1; private EditText num2; private TextView sum; private ServiceConnection conn; //自定义的公共接口,用于求两数之和 private SumOfTwo sumOfTwo; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); num1 = (EditText)this.findViewById(R.id.num1); num2 = (EditText)this.findViewById(R.id.num2); sum = (TextView)this.findViewById(R.id.sum); Button button = (Button)this.findViewById(R.id.button); button.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { sum(); } }); conn = new SumConnetion(); Intent service = new Intent(this, SumService.class); this.bindService(service, conn, BIND_AUTO_CREATE); } protected void sum() { int number1 = Integer.valueOf(num1.getText().toString()); int number2 = Integer.valueOf(num2.getText().toString()); int result = sumOfTwo.sum(number1, number2); sum.setText(String.valueOf(result)); } private class SumConnetion implements ServiceConnection{ @Override public void onServiceConnected(ComponentName name, IBinder service) { sumOfTwo = (SumOfTwo)service; } @Override public void onServiceDisconnected(ComponentName name) { sumOfTwo = null; } } @Override protected void onDestroy() { unbindService(conn); super.onDestroy(); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; }}
服务端代码
package com.njulya.intsum;import android.app.Service;import android.content.Intent;import android.os.Binder;import android.os.IBinder;public class SumService extends Service { @Override public IBinder onBind(Intent intent) { // TODO Auto-generated method stub return new SumBinder(); } public class SumBinder extends Binder implements SumOfTwo{ @Override public int sum(int number1, int number2) { return number1 + number2; } }}
Android专题8——本地服务和远程服务通信
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