AIDL是一个缩写，全称是Android Interface Definition Language，也就是Android接口定义语言.
设计这门语言的目的是为了实现进程间通信，尤其是在涉及多进程并发情况下的进程间通信。
学习这个是在Service的远程服务调用时会遇到这个问题。
service的调用分本地调用和远程服务调用。本地其实就是同一个应用之间的调用，远程服务调用就是不同应用之间的调用。比如淘宝里的芭芭农场调用支付宝里的芭芭农场，是两个应用之间的调用。
案例：
客户端
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<Button
android:id="@+id/button1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:onClick="bindRemoteService"
android:text="bind remote Service" />
<EditText
android:id="@+id/et_aidl_id"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="学员ID"
android:text="3" />
<Button
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:onClick="invokeRemote"
android:text="调用远程服务端的方法" />
<Button
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:onClick="unbindRemoteService"
android:text="unbind remote Service" />
</LinearLayout>
服务端，由于是暴露服务，是不用界面的，只要编写好AIDL文件，拷贝一份到客户端，就可以进行调用了。在我们的服务端项目中，同时演示了调用本地的Service
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="1. 测试启动本地服务"
android:textSize="25sp" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<Button
android:id="@+id/button1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:onClick="startMyService"
android:text="启动服务" />
<Button
android:id="@+id/button2"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:onClick="stopMyService"
android:text="停止服务" />
</LinearLayout>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:text="2. 测试绑定本地服务"
android:textSize="25sp" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<Button
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:onClick="bindMyService"
android:text="绑定服务" />
<Button
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:onClick="unbindMyService"
android:text="解绑服务" />
</LinearLayout>
</LinearLayout>
处理MainActivity.java
package com.hbk.servicedemo;
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.util.Log;
import android.view.View;
import android.widget.Toast;
import com.hbk.servicedemo.local.MyService;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
//启动服务
public void startMyService(View v) {
Intent intent = new Intent(this, MyService.class);
startService(intent);
Toast.makeText(this, "start service", 0).show();
}
public void stopMyService(View v) {
Intent intent = new Intent(this, MyService.class);
stopService(intent);
Toast.makeText(this, "stop service", 0).show();
}
private ServiceConnection conn;
//绑定服务
public void bindMyService(View v) {
Intent intent = new Intent(this, MyService.class);
//创建连接对象
if(conn==null) {
conn = new ServiceConnection() {
@Override
public void onServiceDisconnected(ComponentName name) {
Log.e("TAG", "onServiceDisconnected()");
}
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
Log.e("TAG", "onServiceConnected()");
}
};
//绑定Service
bindService(intent, conn, Context.BIND_AUTO_CREATE);
Toast.makeText(this, "bind service", 0).show();
} else {
Toast.makeText(this, "已经bindservice", 0).show();
}
}
//解绑服务
public void unbindMyService(View v) {
if(conn!=null) {
unbindService(conn);
conn = null;
Toast.makeText(this, "unbind service", 0).show();
} else {
Toast.makeText(this, "还没有bindservice", 0).show();
}
}
//在Activity死亡之前调用
@Override
protected void onDestroy() {
super.onDestroy();
if(conn!=null) {
unbindService(conn);
conn = null;
}
}
}
本地Service,主要重点掌握如下API即可
.startService(Intent service)
stopService(Intent name)
bindService(Intent service, ServiceConnection conn, int flags)
unbindService(ServiceConnection conn)
远程Service,先定义AIDL文件，如我们新建IStudentService.aidl(可以新建interface，然后重命名)
IStudentService.aidl，同包下的类也需要import(注意)
package com.hbk.servicedemo.remote;
import com.hbk.servicedemo.remote.Student;
interface IStudentService {
Student getStudentById(int id);
}
第二步，实体类需要实现Parcelable接口
Student.java
package com.hbk.servicedemo.remote;
import android.os.Parcel;
import android.os.Parcelable;
import android.util.Log;
public class Student implements Parcelable {
private int id;
private String name;
private double price;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
@Override
public String toString() {
return "Student [id=" + id + ", name=" + name + ", price=" + price + "]";
}
public Student(int id, String name, double price) {
super();
this.id = id;
this.name = name;
this.price = price;
}
public Student() {
super();
// TODO Auto-generated constructor stub
}
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
Log.e("TAG", "打包 writeToParcel()");
dest.writeInt(id);
dest.writeString(name);
dest.writeDouble(price);
}
// 添加一个静态成员,名为CREATOR,该对象实现了Parcelable.Creator接口
public static final Parcelable.Creator<Student> CREATOR = new Parcelable.Creator<Student>() {
@Override
public Student createFromParcel(Parcel source) {
// id
int id = source.readInt();
// name
String name = source.readString();
// price
double price = source.readDouble();
return new Student(id, name, price);
}
@Override
public Student[] newArray(int size) {
return new Student[size];
}
};
}
固定模式，public static final Parcelable.Creator<Student> CREATOR，名字一定叫CREATOR，注意序列化的顺序，即打包读写顺序要一致。
第三步，新建Student.aidl文件
package com.hbk.servicedemo.remote; parcelable Student;
清单文件中注册service
<service android:name="com.hbk.servicedemo.local.MyService"/>
<service android:name="com.hbk.servicedemo.remote.MyRemoteService">
<intent-filter>
<action android:name="com.hbk.servicedemo.remote.MyRemoteService.Action"/>
</intent-filter>
</service>
定义Action，主要是为了给客户端进行调用
客户端处理Activity
package com.hbk.servicedemoclient;
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.RemoteException;
import android.util.Log;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;
import com.hbk.servicedemo.remote.IStudentService;
import com.hbk.servicedemo.remote.Student;
public class MainActivity extends Activity {
private EditText et_aidl_id;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
et_aidl_id = (EditText) findViewById(R.id.et_aidl_id);
}
private ServiceConnection conn;
private IStudentService studentService;
// 绑定远程服务
public void bindRemoteService(View v){
Intent intent = new Intent("com.hbk.servicedemo.remote.MyRemoteService.Action");
if(conn == null){
conn = new ServiceConnection() {
@Override
public void onServiceDisconnected(ComponentName name) {
// TODO Auto-generated method stub
}
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
Log.e("TAG", "onServiceConnected()");
studentService = IStudentService.Stub.asInterface(service);
}
};
bindService(intent, conn, Context.BIND_AUTO_CREATE);
Toast.makeText(this, "绑定Service", 0).show();
}
}
public void invokeRemote(View v) throws RemoteException {
if(studentService!=null) {
int id = Integer.parseInt(et_aidl_id.getText().toString());
Student student = studentService.getStudentById(id);
Toast.makeText(this, student.toString(), 0).show();
}
}
public void unbindRemoteService(View v) {
if (conn != null) {
unbindService(conn);
conn = null;
studentService = null;
Toast.makeText(this, "解绑Service", 0).show();
} else {
Toast.makeText(this, "还未绑定Service", 0).show();
}
}
}
绑定的时候，传入服务端的action
Intent intent = new Intent(“com.hbk.servicedemo.remote.MyRemoteService.Action”);
服务连接的时候，初始化业务服务
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
Log.e("TAG", "onServiceConnected()");
studentService = IStudentService.Stub.asInterface(service);
}
测试
