本文講述aidl的簡單使用

首先我們來看綁定本地service的用法：

第一步：創建接口和實體類

public interface IController {
    public User getUser(int index);
}

public class User {
    private int age;
    private String name;
    public User(int age, String name) {
        super();
        this.age = age;
        this.name = name;
    }
    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;
    }

}

第二步：創建本地service

public class MyService extends Service {

    public MyBinder mBinder = new MyBinder();

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

    public class MyBinder extends Binder implements IController{

        @Override
        public User getUser(int index) {
            // 這裡返回查詢的結果
            return new User(20, "panpan");
        }

    }

}

第三步：綁定/解綁服務

public class TwoActivity extends Activity {

    private IController con;
    private MyConn conn;
    private TextView tv;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_two);
        tv = (TextView) findViewById(R.id.tv);

        Intent service = new Intent(getApplicationContext(), MyService.class);
        conn = new MyConn();
        bindService(service, conn, BIND_AUTO_CREATE);
    }

    public void two(View v){
        User user = con.getUser(1);
        tv.setText(user.getName()+":"+user.getAge()+"歲");
    }

    private class MyConn implements ServiceConnection{

        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            //綁定本地服務可以強制轉換，綁定遠程服務不可以，後面有講
            con = (IController) service;
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {
        }

    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        unbindService(conn);//一定不要忘記這一步
    }

}

最後不要忘記在AndroidManifest中注冊service

以上代碼很簡單，不做解釋

---

再來看看綁定遠程服務的用法：

我們以兩個Android工程來模擬客服端和服務端程序

服務端代碼：

創建一個接口：

public interface IController {
    public User getUser(int index);
}

創建一個實體類，實現Parcelable接口

public class User implements Parcelable {
    private int age;
    private String name;

    public User(int age, String name) {
        super();
        this.age = age;
        this.name = name;
    }

    public User(Parcel in) {
        age = in.readInt();
        name = in.readString();
    }

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeInt(age);
        dest.writeString(name);
    }

    public static final Parcelable.Creator CREATOR = new Parcelable.Creator() {
        public User createFromParcel(Parcel in) {
            return new User(in);
        }

        public User[] newArray(int size) {
            return new User[size];
        }
    };

    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;
    }

}

在Navigator視圖中將接口IController.java後綴名.Java修改為.aidl(包視圖修改不了)

修改好後切回包視圖（Package Explorer），IController.aidl報錯

根據提示把兩個public刪掉並為實體類User加上描述文件，在User類所在包右鍵->New->File，創建同名的.aidl文件，即：User.aidl

User.aidl的內容就兩行

此時可以發現gen目錄下自動產生了IController.aidl的Java語言解釋類IController.java

內容如下

package com.ipjmc.scroller.contro;
public interface IController extends android.os.IInterface
{
/** Local-side IPC implementation stub class. */
public static abstract class Stub extends android.os.Binder implements com.ipjmc.scroller.contro.IController
{
private static final java.lang.String DESCRIPTOR = "com.ipjmc.scroller.contro.IController";
/** Construct the stub at attach it to the interface. */
public Stub()
{
this.attachInterface(this, DESCRIPTOR);
}
/**
 * Cast an IBinder object into an com.ipjmc.scroller.contro.IController interface,
 * generating a proxy if needed.
 */
public static com.ipjmc.scroller.contro.IController asInterface(android.os.IBinder obj)
{
if ((obj==null)) {
return null;
}
android.os.IInterface iin = obj.queryLocalInterface(DESCRIPTOR);
if (((iin!=null)&&(iin instanceof com.ipjmc.scroller.contro.IController))) {
return ((com.ipjmc.scroller.contro.IController)iin);
}
return new com.ipjmc.scroller.contro.IController.Stub.Proxy(obj);
}
@Override public android.os.IBinder asBinder()
{
return this;
}
@Override public boolean onTransact(int code, android.os.Parcel data, android.os.Parcel reply, int flags) throws android.os.RemoteException
{
switch (code)
{
case INTERFACE_TRANSACTION:
{
reply.writeString(DESCRIPTOR);
return true;
}
case TRANSACTION_getUser:
{
data.enforceInterface(DESCRIPTOR);
int _arg0;
_arg0 = data.readInt();
com.ipjmc.scroller.entity.User _result = this.getUser(_arg0);
reply.writeNoException();
if ((_result!=null)) {
reply.writeInt(1);
_result.writeToParcel(reply, android.os.Parcelable.PARCELABLE_WRITE_RETURN_VALUE);
}
else {
reply.writeInt(0);
}
return true;
}
}
return super.onTransact(code, data, reply, flags);
}
private static class Proxy implements com.ipjmc.scroller.contro.IController
{
private android.os.IBinder mRemote;
Proxy(android.os.IBinder remote)
{
mRemote = remote;
}
@Override public android.os.IBinder asBinder()
{
return mRemote;
}
public java.lang.String getInterfaceDescriptor()
{
return DESCRIPTOR;
}
@Override public com.ipjmc.scroller.entity.User getUser(int index) throws android.os.RemoteException
{
android.os.Parcel _data = android.os.Parcel.obtain();
android.os.Parcel _reply = android.os.Parcel.obtain();
com.ipjmc.scroller.entity.User _result;
try {
_data.writeInterfaceToken(DESCRIPTOR);
_data.writeInt(index);
mRemote.transact(Stub.TRANSACTION_getUser, _data, _reply, 0);
_reply.readException();
if ((0!=_reply.readInt())) {
_result = com.ipjmc.scroller.entity.User.CREATOR.createFromParcel(_reply);
}
else {
_result = null;
}
}
finally {
_reply.recycle();
_data.recycle();
}
return _result;
}
}
static final int TRANSACTION_getUser = (android.os.IBinder.FIRST_CALL_TRANSACTION + 0);
}
public com.ipjmc.scroller.entity.User getUser(int index) throws android.os.RemoteException;
}

創建服務端service

public class MyService extends Service {

    public MyBinder mBinder = new MyBinder();

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

    // 繼承Stub就可以了，因為在IController.java中Stub就extends android.os.Binder 並且implements com.ipjmc.scroller.contro.IController，是不是覺得和綁定本地服務的時候有點像？
    public class MyBinder extends Stub{

        @Override
        public User getUser(int index) {
            // 這裡返回查詢的結果
            return new User(20, "panpan");
        }

    }

}

在AndroidManifest中注冊service時添加過濾器intent-filter，因為跨進程訪問service我們使用隱私意圖

到此，服務端coding完成

---

再來看看客戶端代碼：

第一步：拷貝服務端以下內容到客戶端src下（帶包拷貝）

像這樣

然後在Activity中綁定遠程服務

public class MainActivity extends Activity {

    private TextView tv;
    private MyConn conn;
    private IController controller;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
         tv = (TextView) findViewById(R.id.tv);

         Intent intent = new Intent("com.ipjmc.scroller.serveice.MyService");
         conn = new MyConn();
         bindService(intent, conn, BIND_AUTO_CREATE);
    }

    public class MyConn implements ServiceConnection{

        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            // TODO Auto-generated method stub
            controller = Stub.asInterface(service);
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {
        }

    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        unbindService(conn);
    }

    public void two(View v){
        try {
            User user = controller.getUser(1);
            tv.setText(user.getName()+":"+user.getAge()+"歲");
        } catch (RemoteException e) {
            e.printStackTrace();
        }
    }

}

客戶端coding完成，但是需要注意的是，在Android5.0及以後，Android系統出於安全考慮，禁止隱士調用方式，程序運行報錯：java.lang.IllegalArgumentException: Service Intent must be explicit，網上搜索到的解決方法：

    //添加一個方法
    public static Intent createExplicitFromImplicitIntent(Context context, Intent implicitIntent) {  
        // Retrieve all services that can match the given intent  
        PackageManager pm = context.getPackageManager();  
        List resolveInfo = pm.queryIntentServices(implicitIntent, 0);  

        // Make sure only one match was found  
        if (resolveInfo == null || resolveInfo.size() != 1) {  
            return null;  
        }  

        // Get component info and create ComponentName  
        ResolveInfo serviceInfo = resolveInfo.get(0);  
        String packageName = serviceInfo.serviceInfo.packageName;  
        String className = serviceInfo.serviceInfo.name;  
        ComponentName component = new ComponentName(packageName, className);  

        // Create a new intent. Use the old one for extras and such reuse  
        Intent explicitIntent = new Intent(implicitIntent);  

        // Set the component to be explicit  
        explicitIntent.setComponent(component);  

        return explicitIntent;  
    }  

    Intent i = new Intent("com.ipjmc.scroller.serveice.MyService");
    Intent intent = new Intent(createExplicitFromImplicitIntent(this,i));  
    conn = new MyConn();
    bindService(intent, conn, BIND_AUTO_CREATE);