Android 使用AIDL调用外部服务

Posted on 2013-07-15 21:16 work hard work smart 阅读(11849) 评论(1) 编辑收藏举报

好处：多个应用程序之间建立共同的服务机制，通过AIDL在不同应用程序之间达到数据的共享和数据相互操作，

本文包括： 1 、创建AIDL 服务端。2 、创建AIDL 客户端。 3、客户端调用服务端提供的服务接口。

1、创建AIDL 服务端。

在Android的src中新建IStudentService.aidl

package com.example.studentservice;
import com.example.studentservice.Student;;
 
interface IStudentService
{
    Map getMap(in String test_class,in Student student);
    Student getStudent();
 
}

Student 类是一个序列化的类，这里使用Parcelable 接口来序列化. Student 类代码如下：

package com.example.studentservice;
 
import android.os.Parcel;
import android.os.Parcelable;
 
public class Student implements Parcelable{
    private int age;
    private String name;
 
    public Student(Parcel source) {
        // TODO Auto-generated constructor stub
        age = source.readInt();
        name = source.readString();
    }
 
    public Student() {
        // TODO Auto-generated constructor stub
    }
 
    public int getAge() {
        return age;
    }
 
    public void setAge(int age) {
        this.age = age;
    }
 
    public String getName() {
        return name;
    }
 
    public void setName(String name) {
        this.name = name;
    }
     
     
    public static final Parcelable.Creator<Student> CREATOR = new Creator<Student>() {
         
        @Override
        public Student[] newArray(int size) {
            // TODO Auto-generated method stub
            return new Student[size];
        }
         
        @Override
        public Student createFromParcel(Parcel source) {
            // TODO Auto-generated method stub
            return new Student(source);
        }
    };
 
    @Override
    public int describeContents() {
        // TODO Auto-generated method stub
        return 0;
    }
 
    @Override
    public void writeToParcel(Parcel dest, int flags) {
        // TODO Auto-generated method stub
        dest.writeInt(age);
        dest.writeString(name);
    }
 
 
}

在这里必须注意如下三点：

1.在Student 类中必须有一个静态常量，常量名必须是CREATOR，而且CREATOR 常量的数据类型必须是 Parcelable.Creator

2.在writeToParcel 方法中需要将要序列化的值写入到 Parcel对象中。

3.编写完Student 为时，必须再新建一个Student.aidl 文件，此文件输入以下内容：
parcelable Student; 这里的书写是供上面我们说过的接口 *.aidl 文件导包时可以找到，并通过此文件找到Student类对象。

如果上面的步骤顺利通过的话，Android 将会自动在gen 目录下R文件的相同目录生成一个以*.aidl 文件命名的*.java 文件，如下图：

顺利生成成功后，我们再来编写一个AIDL 服务类，代码如下：

package com.example.studentservice;
import java.util.HashMap;
import java.util.Map;
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.os.RemoteException;
 
 
public class StudentService extends Service{
 
    @Override
    public IBinder onBind(Intent intent) {
        // TODO Auto-generated method stub
        return new StudentServiceImple();
    }
     
    public class StudentServiceImple extends IStudentService.Stub {
         
        @Override
        public Student getStudent() throws RemoteException
        {
            Student student = new Student();
            student.setAge(25);
            student.setName("Zhang san");
            return student;
        }
 
        @Override
        public Map getMap(String test_class, Student student)
                throws RemoteException {
            // TODO Auto-generated method stub
              Map<String, Object> map = new HashMap<String, Object>();
                map.put("class", "06109091");
                map.put("age", student.getAge());
                map.put("name", student.getName());
                return map;
 
        }
    }
 
}

如上代码，StudentService服务类有一个子类并继承自我们上面生成的*.java 文件重写其中我们在*.aidl 中声明的两个接口方法，实现了其功能。上面IBinder 必须返回此服务类的子类对象，否则客户端将无法获得服务对象。

最后，即然有服务的操作，那么就得在manifest文件中注册服务类，代码如下：

<service android:name=".StudentService"  android:exported="true"  android:enabled="true"
    android:process=":remote">
    <intent-filter>
        <action android:name="com.example.studentservice.IStudentService"></action>
        </intent-filter>
</service>

至此，服务端就己经开发完成了，下面接着开发客启端。

2、创建AIDL 客户端

同样是新建一个项目，这里要注意，需要将服务端生成成功后的gen 目录下的包复制过来，放到我们新建项目的src 文件夹下，如下图：

因为IServiceService 这个生成类，引用到了Student, 所以这里一并将Student也复制过来。

至此，客户端的创建己经完毕，下面我们就要利用创建的客户端去调用服务端的方法。

3、客户端调用服务端提供的服务接口

package com.example.studentclient;
 
import com.example.studentservice.IStudentService;
 
import android.os.Bundle;
import android.os.IBinder;
import android.os.RemoteException;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.ComponentName;
import android.content.Context;
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;
 
public class MainActivity extends Activity {
    private Button btn1, btn2; 
    private IStudentService stuService = null;
    private ServiceConnection serviceConnection = new ServiceConnection() {
         
        @Override
        public void onServiceDisconnected(ComponentName name) {
            // TODO Auto-generated method stub
             
        }
         
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            // TODO Auto-generated method stub
            stuService = IStudentService.Stub.asInterface(service);
        }
    };
         
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btn1 = (Button)findViewById(R.id.button1);
        btn2 = (Button)findViewById(R.id.button2);
        btn1.setOnClickListener(new OnClickListener() {
             
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                bindService(new Intent("com.example.studentservice.IStudentService"), 
                        serviceConnection, Context.BIND_AUTO_CREATE);//;
            }
        });
        btn2.setOnClickListener(new OnClickListener() {
             
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                StringBuilder sb = new StringBuilder();
                try {
                    if (stuService == null) {
                        new AlertDialog.Builder(MainActivity.this).setTitle("Error")
                        .setMessage("stuService is null").setPositiveButton(
                                android.R.string.ok, null).show();
 
                        return;
                    }
                    sb.append("学生名称为：" + stuService.getStudent().getName() + "\n");
                    sb.append("年龄为：" + stuService.getStudent().getAge() + "\n");
                    sb.append("map 对象内容为如下："
                            + stuService.getMap("中国", stuService.getStudent())
                                    .toString());
                } catch (RemoteException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                new AlertDialog.Builder(MainActivity.this).setTitle("调用外部服务")
                        .setMessage(sb.toString()).setPositiveButton(
                                android.R.string.ok, null).show();
 
            }
        });
    }
 
}