Binder機制的應用——雙應用間的通訊

時間 2019-11-07

標籤 binder 機制應用用間通訊简体版

原文原文鏈接

前言

以前的一篇文章說過了Binder機制的總結與應用，裏面的是《Android開發藝術探索》一書的例子，今天特地將Binder機制應用到雙應用之間的通訊上，看是否能夠實現跨進程的通訊。java

客戶端

一、首先建立兩個aidl文件，分別爲Phone.aidl、IPhoneManager.aidl，分別表示一個實體類和一個管理類。以下圖所示： android

Phone.aidl的具體代碼以下：ios

// Phone.aidl
package com.example.runningh.myapplication.phone;

// Declare any non-default types here with import statements

parcelable Phone;
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IPhoneManager.aidl的具體代碼以下：bash

// IPhoneManager.aidl
package com.example.runningh.myapplication.phone;
import com.example.runningh.myapplication.phone.Phone;

// Declare any non-default types here with import statements

interface IPhoneManager {
    List<Phone> getPhoneList();
    void addPhone(in Phone phone);
}
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二、而後建立Phone.java類，Phone.java類的package路徑必需要和上面建立的Phone.aidl路徑保持一致，不然即便IPhoneManager.java類編譯出來了仍是會報錯。上面的例子，Phone.java的package路徑爲com.example.runningh.myapplication.phone，以下圖所示： app

Phone.java的代碼以下所示：ide

package com.example.runningh.myapplication.phone;

import android.os.Parcel;
import android.os.Parcelable;

/**
 * Created by RunningH on 2018/1/11.
 */

public class Phone implements Parcelable {

    public String phoneName;
    public int price;
    public int density;

    public Phone(String phoneName, int price, int density) {
        this.phoneName = phoneName;
        this.price = price;
        this.density = density;
    }

    protected Phone(Parcel in) {
        this.phoneName = in.readString();
        this.price = in.readInt();
        this.density = in.readInt();
    }


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

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

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

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeString(phoneName);
        dest.writeInt(price);
        dest.writeInt(density);
    }
}
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三、接着執行build命令，生成IPhoneManager.java文件，具體能夠在build/generated/source/aidl/debug/xxx下面找到，例如我本身的就是在build/generated/source/aidl/debug/com.example.runningh.myapplication/phone目錄下，以下圖所示：佈局

四、最後就是編寫客戶端和服務端的通訊類了，咱們使用PhoneActivity啓動服務端的遠程服務來和服務端進行通訊。以下是PhoneActivity類的代碼：ui

package com.example.runningh.myapplication.phone;

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.support.annotation.Nullable;
import android.util.Log;
import android.widget.TextView;

import com.example.runningh.myapplication.R;

import java.util.List;

/**
 * Created by RunningH on 2018/1/11.
 */

public class PhoneActivity extends Activity {
    TextView phoneListView;
    TextView phonePriceView;
    private TextView phoneDensityView;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.phone_activity);
        phoneListView = (TextView) findViewById(R.id.phone_list);
        phonePriceView = (TextView) findViewById(R.id.phone_price);
        phoneDensityView = (TextView) findViewById(R.id.phone_density);
        getDataFromRemote();
    }

    private void getDataFromRemote() {
        //這裏的」com.example.runningh.phoneservice"是後面服務端Service定義的action的名字 Intent intent = new Intent("com.example.runningh.phoneservice"); //這裏的"com.example.runningh.myapplicationtest"爲服務端APP的包名，不設置會報錯 intent.setPackage("com.example.runningh.myapplicationtest"); bindService(intent, new ServiceConnection() { @Override public void onServiceConnected(ComponentName name, IBinder service) { //獲取服務端的IPhoneManager對象的代理 IPhoneManager iPhoneManager = IPhoneManager.Stub.asInterface(service); try { final List<Phone> phoneList = iPhoneManager.getPhoneList(); //獲取服務端的Phone列表 if (phoneList != null && phoneList.size() > 0) { final StringBuilder nameBuilder = new StringBuilder(); final StringBuilder priceBuilder = new StringBuilder(); final StringBuilder densityBuilder = new StringBuilder(); for (Phone phone : phoneList) { nameBuilder.append("phoneName=" + phone.phoneName + "; "); priceBuilder.append("price=" + phone.price + "; "); densityBuilder.append("density=" + phone.density + "; "); } //因爲這裏是在子線程，因此展現信息時要在主線程運行 runOnUiThread(new Runnable() { @Override public void run() { phoneListView.setText(nameBuilder.toString()); phonePriceView.setText(priceBuilder.toString()); phoneDensityView.setText(densityBuilder.toString()); } }); //客戶端將新建一個Phone類添加到服務端 iPhoneManager.addPhone(new Phone("vivo", 2900, 2000)); } } catch (RemoteException e) { e.printStackTrace(); } } @Override public void onServiceDisconnected(ComponentName name) { } }, BIND_AUTO_CREATE); } } 複製代碼

上面簡單地在Activity中開啓了一個遠程服務，鏈接到了服務端，並獲取服務端的代理對象，而後獲取服務端的信息，同時也實現了將客戶端的信息添加到服務端。佈局文件的代碼就不貼出來了，也就是幾個TextView，來對服務端的信息進行展現。this

特別須要注意的是，客戶端鏈接服務端對象時，還要設置服務端的包名，不然會報錯。如上面的代碼所示，使用intent.setPackage設置了服務端的包名。spa

服務端

一、將客戶端的兩個aidl文件，Phone.aidl、IPhoneManager.aidl複製到服務端，而且保持package路徑一致。以下圖所示：

二、將客戶端的實體類Phone.java複製到服務端，而且保持package路徑一致。以下圖所示：

三、定義一個服務類，PhoneService.java，客戶端開啓的服務就是這個服務，在這個服務中返回服務端的代理對象給到客戶端。代碼以下所示：

package com.example.runningh.myapplication;

import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;
import android.os.RemoteException;
import android.support.annotation.Nullable;

import com.example.runningh.myapplication.phone.IPhoneManager;
import com.example.runningh.myapplication.phone.Phone;

import java.util.ArrayList;
import java.util.List;

/**
 * Created by RunningH on 2018/1/12.
 */

public class PhoneService extends Service {
    private Binder myBinder = new IPhoneManager.Stub() {
        @Override
        public List<Phone> getPhoneList() throws RemoteException {
            Phone phone = new Phone("android", 1000, 500);
            List<Phone> phones = new ArrayList<>();
            phones.add(phone);
            phones.add(new Phone("ios", 5000, 1000));
            return phones;
        }

        @Override
        public void addPhone(Phone phone) throws RemoteException {
            Intent intent = new Intent();
            intent.putExtra("phone", phone);
            intent.setAction("test");
            sendBroadcast(intent); //將客戶端發過來的信息經過廣播的形式發送給Activity，Activity再進行展現。
        }
    };

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return myBinder; //返回一個代理對象給客戶端
    }
}
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還記得客戶端鏈接服務端Service的代碼嗎？該Service就是客戶端須要啓動的對象。咱們須要在Manifest中註冊該Service，而且設置過濾的Action。以下所示：

<service android:name="com.example.runningh.myapplication.PhoneService">
      <intent-filter>
          <action android:name="com.example.runningh.phoneservice" />
      </intent-filter>
</service>
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四、新建一個Activity，叫作MainActivity好了。裏面要作的事情是註冊一個廣播並監聽PhoneService發過來的內容，對客戶端的信息進行展現。具體代碼以下：

package com.example.runningh.myapplication;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Parcelable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;

import com.example.runningh.myapplication.phone.Phone;
import com.example.runningh.myapplicationtest.R;

public class MainActivity extends AppCompatActivity {

    private TextView infoView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        infoView = (TextView) findViewById(R.id.info);
        registerReceiver(new MyReceiver(), new IntentFilter("test"));
    }


    class MyReceiver extends BroadcastReceiver {

        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            if (action.equals("test")) {
                final Phone phone = intent.getParcelableExtra("phone");
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        infoView.setText("phone.name=" + phone.phoneName + "; phone.price=" + phone.price + "; phone.desity=" + phone.density);
                    }
                });
            }
        }
    }
}
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