Android下的IPC通信方式_ZenDei技術網路在線

一、Bundle Android的Activity、Service、Receiver都支持在Intent傳遞Bundle數據,Bundle實現了Parcelable介面, 所以能很方便的在不同進程之間進行數據傳傳輸.比如A應用打開B應用的某個Activity,如果要傳遞自定義的類型, 可以繼承自Pa ...

一、Bundle

Android的Activity、Service、Receiver都支持在Intent傳遞Bundle數據,Bundle實現了Parcelable介面,

所以能很方便的在不同進程之間進行數據傳傳輸.比如A應用打開B應用的某個Activity,如果要傳遞自定義的類型,

可以繼承自Parcelable介面,參考Parcelable的使用方式 Android序列化的幾種實現方式

A頁面:

public class MainActivity extends AppCompatActivity {
    private final static int OPEN_OTHER_ACTIVITY_REQUEST_CODE = 0;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
	setContentView(R.layout.activity_main);

	Intent intent = new Intent();
	String packageName = "komine.demos.ipcdemo2";
	String activityName = packageName + ".MainActivity";
	intent.putExtra("msg","來自komine.demos.ipc傳遞的參數");
	ComponentName componentName = new ComponentName(packageName,activityName);
	intent.setComponent(componentName);

	startActivityForResult(intent,OPEN_OTHER_ACTIVITY_REQUEST_CODE);
    }
  
    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        if(data != null){
            if(requestCode == OPEN_OTHER_ACTIVITY_REQUEST_CODE){
                Toast.makeText(getApplicationContext(),data.getStringExtra("value"),Toast.LENGTH_SHORT).show();
            }
        }
    }
}

B頁面:

public class MainActivity extends AppCompatActivity {

    private final static int RESULT_CODE = 0;
    private TextView textView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
	setContentView(R.layout.activity_main);

	textView = findViewById(R.id.tv);
        if(getIntent() != null){
            String msg = getIntent().getStringExtra("msg");
            textView.setText(msg);
        }
    }

    @Override
    public void onBackPressed() {
       Intent intent = new Intent();
       intent.putExtra("value","來自komine.demos.ipcdemo2的MainActivity頁面返回的值");
       setResult(RESULT_CODE,intent);

       finish();
    }
}

二、Messenger

1.基本使用

Messenger是基於AIDL的一種輕量化跨進程通信方式,內部是通過Handler進行消息發送的

首先新建一個MessengerService類

public class MessengerService extends Service implements Handler.Callback {

    private static final String TAG = "MessengerService";
    public static final int CLIENT_WHAT = 1;
    public static final int SERVER_WHAT = 2;

    //服務端接收到一條消息就會向客戶端發送一條回覆消息
    @Override
    public boolean handleMessage(@NonNull Message msg) {
        if (msg.what == CLIENT_WHAT) {
            Log.d(TAG, "收到來自客戶端的消息:" + msg.getData());

	    //msg.replyTo是客戶端定義的Messenger對象,用來向客戶端發送消息
	    Messenger client = msg.replyTo;
            Message replyMessage = Message.obtain(null, SERVER_WHAT);

	    Bundle bundle = new Bundle();
	    bundle.putString("reply", "服務端回覆客戶端的數據..." + new Date());
	    replyMessage.setData(bundle);

            try {
		//調用客戶端的Messenger對象向客戶端發送消息
                client.send(replyMessage);
	    } catch (Exception e) {
                e.printStackTrace();
	    }
        }
        return false;
    }

    //服務端的Messenger對象,客戶端可以通過onBind中返回的IBinder對象
    //來實例化一個Messenger對象,用來向服務端發送Message,Messenger內部採用
    //的是Message來進行消息傳遞,所以需要一個Handler對象來進行消息發送
    private final Messenger mMessenger = new Messenger(new Handler(Looper.getMainLooper(),this));

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
	//返回Messenger的Binder對象
        return mMessenger.getBinder();
    }
}

在AndroidManifest.xml註冊MessengerService,該服務運行在另外一個進程中,冒號開頭表示在當前進程名之前加上完整的包名,

並且該進程為應用的私有進程,不以冒號開頭,則表示全局進程,其他可以通過sharedUserId的方式將自己運行在同一個進程中,比如

sharedUserId = "android.uid.system",將自己運行在系統進程中,以取得系統進程的一些許可權,以這種方式運行在一起的進程之間

可以互相訪問對方的私有數據,比如data目錄、files目錄,另外簽名要保持一致才行,debug版本不需要.

註冊MessengerService

<service android:name="komine.demos.messager.MessengerService" android:process=":remote"/>

MainActivity,佈局就一個按鈕,綁定了sendMsg方法就不貼代碼了

public class MainActivity extends AppCompatActivity implements ServiceConnection,Handler.Callback {

    private Messenger mService;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
  	setContentView(R.layout.activity_main);

	//綁定遠程Service
	bindService(new Intent(this, MessengerService.class),this,Context.BIND_AUTO_CREATE);
    }

    @Override
    public void onServiceConnected(ComponentName name, IBinder service) {
        //通過IBinder對象創建一個Messenger實例
	mService = new Messenger(service);
    }

    //點擊發送按鈕就會向服務端發送一條Message
    public void sendMsg(View view) {
        Message msg = Message.obtain(null,MessengerService.CLIENT_WHAT);

	Bundle data = new Bundle();
	data.putString("msg","hello,this is client");
	msg.setData(data);

	//指定當前消息是那個Messenger對象發送的,該對象就是我們在服務端
	//向客戶端發送Message的Messenger對象
	msg.replyTo = mGetReplyMessenger;
        try{
            mService.send(msg);
	}catch (RemoteException e){
            e.printStackTrace();
	}
    }

    @Override
    public void onServiceDisconnected(ComponentName name) {

    }

    //客戶端的Messenger對象
    private Messenger mGetReplyMessenger = new Messenger(new Handler(Looper.getMainLooper(),this));

    //處理服務端發送回來的Message
    @Override
    public boolean handleMessage(@NonNull Message msg) {
        if(msg.what == MessengerService.SERVER_WHAT){
            Log.d("client", "收到來自服務端的消息:" + msg.getData().getString("reply"));
    	}
        return false;
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        if(mService != null && mService.getBinder().isBinderAlive()){
            unbindService(this);
	}
    }
}

客戶端輸出:

服務端輸出:

註意:由於MessengerService是在不同的線程,需要切換進程才能看到對於的日誌輸出

Messenger是通過Handler來實現消息發送的,而Handler的內部是通過消息隊列來維護每一個Message對象,

隊列是一個先進先出的數據結構,所以Messenger無法併發處理多個消息,只能一條一條的處理.

2.綁定其他應用的Service

上述代碼是客戶端和服務端都在同一個應用之內的兩個不同進程,如果要綁定其他應用的xxx服務,需要通過顯式Intent來綁定,
並且遠程Service要設置 exported = "true",不然會拋異常

<service android:name=".MessengerServer" android:exported="true"/>

a.setClassName()方式

intent.setClassName("包名","包名.Service名稱");

b.setComponent() 方式

intent.setComponent(new ComponentName("包名","包名.Service名稱"));

例如:

Intent intent = new Intent();
intent.setComponent(new ComponentName("komine.demos.messenegerserver","komine.demos.messenegerserver.MessengerServer"));

//網上有說直接在bindService()之前調用startService()開啟服務,我試過是無效的,小米Note4x(7.1)可以
//在調用該方法之前,需要在另一端(要綁定的服務所在的應用)開啟對應的Service
//測試環境:模擬器和真機(索尼),Android11必要在對應應用開啟Service才能綁定成功
bindService(intent, this, Context.BIND_AUTO_CREATE);

註意:在在調用bindService()之前,需要遠程進程(指要綁定的服務所在的應用)開啟要綁定的Service,

不然bindService()不報錯,也不會回調onServiceConnected()

三、AIDL

AIDL是Android 介面定義語言,可以通過AIDL在兩個進程之間進行IPC通信.

1.基本使用

新建Game.java

public class Game implements Parcelable {
    public String name;

    public Game(String name){
        this.name = name;
    }

    protected Game(Parcel in) {
        name = in.readString();
    }

    public static final Creator<Game> CREATOR = new Creator<Game>() {
        @Override
	public Game createFromParcel(Parcel in) {
            return new Game(in);
        }

        @Override
	public Game[] newArray(int size) {
            return new Game[size];
	}
    };

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

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

新建Game.aidl

可能會提示名稱不唯一的錯誤,不讓創建,可以先隨便取個名字,然後再重命名,應該是as的bug

Game.aidl 對應 Game.java

// Game.aidl
package komine.demos.ipcdemo3;

// Declare any non-default types here with import statements
//指向Game.java
parcelable Game;

新建IGameShopManager.aidl

// IGameShopManager.aidl
package komine.demos.ipcdemo3;

// Declare any non-default types here with import statements
//引入Game.aild 即使是在同一包名下也需要import
import komine.demos.ipcdemo3.Game;
import komine.demos.ipcdemo3.IDownloadCompleteListener;

interface IGameShopManager {
    boolean buy(float money);
    void download(in IDownloadCompleteListener listener);
    void registerDownloadListener(in IDownloadCompleteListener listener);
    void unregisterDownloadListener(in IDownloadCompleteListener listener);
}

新建IDownloadCompleteListener.aidl

// IDownloadCompleteListener.aidl
package komine.demos.ipcdemo3;

// Declare any non-default types here with import statements
import komine.demos.ipcdemo3.Game;

interface IDownloadCompleteListener {
    void onDownloadCompleted(in Game game);
}

新建EShopManagerService.java

public class EShopManagerService extends Service {

    //Android提供的用於跨進程刪除listener的介面,內部維護了一個Map集合,key是IBinder,通過
    //比對key來刪除對應的listener,如果不使用這個類,而使用普通的集合,在服務解綁,頁面關閉之後,listener也不會
    //移除,可以在迴圈中不斷回調列印日誌試試
    private RemoteCallbackList<IDownloadCompleteListener> listeners = new RemoteCallbackList<>();

    private Binder mBinder = new IGameShopManager.Stub() {
        @Override
	public boolean buy(float money) throws RemoteException {
            return money >= 100;
        }

        @Override
	public void download(IDownloadCompleteListener listener) throws RemoteException {
            Game game = new Game("黑暗之魂重置版");
            try {
                //模擬耗時操作
		Thread.sleep(3000);

		//固定寫法,從RemoteCallbackList取數據的固定寫法
		listeners.beginBroadcast();

                int size = listeners.getRegisteredCallbackCount();

                for (int i = 0;i < size;i++){
                    //Android26+可以使用getRegisteredCallbackItem()方法直接獲取
                    listeners.getBroadcastItem(i).onDownloadCompleted(game);
	      	}

                //固定寫法
		listeners.finishBroadcast();

	   } catch (InterruptedException e) {
                e.printStackTrace();
	   }
        }

        @Override
	public void registerDownloadListener(IDownloadCompleteListener listener) throws RemoteException {
	    //註冊回調介面
            listeners.register(listener);
	}

        @Override
	public void unregisterDownloadListener(IDownloadCompleteListener listener) throws RemoteException {
	    //移除回調介面
            listeners.unregister(listener);
	}
    };

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

註冊EShopManagerService

<service android:name=".EShopManagerService" android:process=":remote"/>

MainActivity.java

public class MainActivity extends AppCompatActivity implements ServiceConnection {
    private IGameShopManager mShopManager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
	setContentView(R.layout.activity_main);

	bindService(new Intent(this,EShopManagerService.class),this, Context.BIND_AUTO_CREATE);
    }

    @Override
    public void onServiceConnected(ComponentName name, IBinder service) {
        mShopManager = IGameShopManager.Stub.asInterface(service);
        try {
	    //註冊回調介面
            mShopManager.registerDownloadListener(downloadCompleteListener);
	} catch (RemoteException e) {
            e.printStackTrace();
	}
    }

    @Override
    public void onServiceDisconnected(ComponentName name) {

    }

    public void buy(View view) throws RemoteException {
        boolean buyResult = mShopManager.buy(100);
        if(buyResult){
            Toast.makeText(getApplicationContext(),"購買成功!",Toast.LENGTH_SHORT).show();
	}
    }

    public void download(View view) {
        try{
            mShopManager.download(downloadCompleteListener);
	}catch (Exception e){
            e.printStackTrace();
	}
    }

    private IDownloadCompleteListener downloadCompleteListener = new IDownloadCompleteListener.Stub() {
        @Override
	public void onDownloadCompleted(final Game game) throws RemoteException {
            runOnUiThread(new Runnable() {
                @Override
		public void run() {
                    Toast.makeText(getApplicationContext(),"下載完成:" + game.name,Toast.LENGTH_SHORT).show();
		}
            });
	}
    };

    @Override
    protected void onDestroy() {
        super.onDestroy();
	//如果mShopManager的Binder未被銷毀
        if(mShopManager != null && mShopManager.asBinder().isBinderAlive()){
            unbindService(this);
            try {
                mShopManager.unregisterDownloadListener(downloadCompleteListener);
	    } catch (RemoteException e) {
                e.printStackTrace();
	    }
        }
    }
}

---------------------------------2022-04-09 更新----------------------------------

2.AIDL綁定遠程服務

綁定過程跟Messenger綁定遠程服務是一致的.

首先將前面生成好的aidl文件夾全部拷貝到另一個app(服務端)中,直接複製main/aidl文件夾,粘貼就好了

註意:客戶端的aidl 文件夾的包名要和服務端的aidl包名一致,複製後會報錯,需要build生成所需的文件.

然後將之前創建的EShopManagerService.java複製到app下的(服務端0)MainActivity同級目錄下,

在AndroidManifest.xml中註冊服務

<service android:name=".EShopManagerService" android:exported="true"/>

然後通過顯式Intent綁定到遠程Service

客戶端綁定服務端Service

Intent intent = new Intent();
intent.setComponent(new ComponentName("包名(應用的包名)","(Service所在文件的包名).服務名稱"));

bindService(intent,this, Context.BIND_AUTO_CREATE);

由於是複製粘貼的,包名有可能填錯,最不會出錯的辦法是直接去Service文件的最上方複製package後面的包名

3.AIDL許可權驗證

預設情況下,我們創建的服務任何人都能綁定,只要知道包名和服務的名稱就可以連接,

那麼如何添加許可權驗證呢

a.在Service的onBind()方法中驗證,只要return null,驗證失敗的客戶端就無法綁定服務

@Nullable
@Override
public IBinder onBind(Intent intent) {
    Boolean noAuthorized = true;
    ...
    ...
    //至於驗證方式有很多,比如在AndroidManifest.xml中自定義permission,然後判斷是否有聲明這個許可權
    //調用checkCallingOrSelfPermission()檢查是否有許可權
    if(!noAuthorized){
        return null;
    }
    return mBinder;
}

服務端AndroidManifest.xml


//申明一個連接到遠程Service所需的自定義許可權
<permission android:name="komine.demos.messenegerserver.EShopManagerService"/>

...
...
//在Service上指定android:permission:komine.demos.messenegerserver.EShopManagerService
<service android:name="komine.demos.ipcdemo3.EShopManagerService" android:exported="true" android:permission="komine.demos.messenegerserver.EShopManagerService"/>

客戶端必須顯式聲明這個許可權,不然會拋許可權拒絕的異常

客戶端AndroidManifest.xml

//komine.demos.messenegerserver.EShopManagerService 在服務端申明的自定義許可權
<uses-permission android:name="komine.demos.messenegerserver.EShopManagerService"/>

b.在服務端的onTransact()驗證

在Service中重寫onTransact()方法,然後進行驗證

private Binder mBinder = new IGameShopManager.Stub() {
    ...
    ...
    @Override
    public boolean onTransact(int code, Parcel data, Parcel reply, int flags) throws RemoteException {
	//驗證方式按自己需求進行選擇,返回false表示驗證失敗
        return super.onTransact(code, data, reply, flags);
}

四、ContentProvider

ContentProvider是Android中提供用於不同應用之間進行數據共用的方式.

1.基本使用

使用很簡單,只需要新建一個類繼承自ContentProvider即可

public class MyContentProvider extends ContentProvider {
    private final static String TAG = "MyContentProvider";

    @Override
    public boolean onCreate() {
        Log.d(TAG,"onCreate...");
        return false;
    }

    @Nullable
    @Override
    public Cursor query(@NonNull Uri uri, @Nullable String[] projection, @Nullable String selection,     @Nullable String[] selectionArgs, @Nullable String sortOrder) {
        Log.d(TAG,"query " + Thread.currentThread().getName());
        return null;
    }

    @Nullable
    @Override
    public String getType(@NonNull Uri uri) {
        return "getType";
    }

    @Nullable
    @Override
    public Uri insert(@NonNull Uri uri, @Nullable ContentValues values) {
        Log.d(TAG,"insert" + Thread.currentThread().getName());
        return null;
    }

    @Override
    public int delete(@NonNull Uri uri, @Nullable String selection, @Nullable String[] selectionArgs) {
        Log.d(TAG,"delete" + Thread.currentThread().getName());
        return 0;
    }

    @Override
    public int update(@NonNull Uri uri, @Nullable ContentValues values, @Nullable String selection, @Nullable String[] selectionArgs) {
        Log.d(TAG,"update" + Thread.currentThread().getName());
        return 0;
    }
}

然後在AndroidManifest.xml的application標簽下註冊

<provider
    android:authorities="komine.demos.ipcdemo4.provider"
    android:exported="true"
    android:name=".MyContentProvider"/>

接下來就能在其他應用中訪問

public class MainActivity extends AppCompatActivity{

    private Messenger mService;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
	setContentView(R.layout.activity_main);
	//authorities:其他應用的provider中定義的authorities值
	//uri = content:// + authorities
	Uri uri = Uri.parse("content://komine.demos.ipcdemo4.provider");
	getContentResolver().query(uri,null,null,null,null);
	getContentResolver().insert(uri,null);
	getContentResolver().delete(uri,null,null);
	getContentResolver().update(uri,null,null,null);
    }
}

Android11+ 更改了應用之間交互的方式,需要在AndroidManifest.xml中添加queries標簽,然後在其中添加目標應用的包名,才能訪問到目標應用提供的ContentProvider.

放在manifest節點

<queries>
    <package android:name="komine.demos.ipcdemo4" />
</queries>