第二章——第二节 IPC机制的概述和使用

一、Serialiable与Paracle

①、作用    ②、使用

二、Binder与AIDL

①、各自的作用

三、如何使用IPC机制

举例

四、IPC机制的原理

①、流程图  ②、自己编译自动生成的Aidl代码

回答：

Serialiable的使用

步骤：1、创建类并继承Serializable接口  2、将对象序列化到文件中 3、从文件中获取序列化的文件

详细步骤：

1、创建Book类，并继承Serializable，编写serialVersionUID降低反序列化失败的概率

public class Book implements Serializable {
    private static final long serialVersionUID = 0X1111L;

    private String name;
    private String author;
    private String publish;

    public Book(String author, String name, String publish) {
        this.author = author;
        this.name = name;
        this.publish = publish;
    }

    @Override
    public String toString() {
        return "Book{" +
                "author='" + author + '\'' +
                ", name='" + name + '\'' +
                ", publish='" + publish + '\'' +
                '}';
    }
}

Book

2、通过Android自带的文件储存器保存文件。

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Book book = new Book("asd","zxc","qweqw");
        try {
            //利用自带的类，创建文件
            FileOutputStream stream = openFileOutput("serialiable",MODE_APPEND);
            ObjectOutputStream dos = new ObjectOutputStream(stream);
            //将Book对象序列化
            dos.writeObject(book);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //layout中对Button使用 android:onClick="launchSecondActivity"
    public void launchSecondActivity(View view){
        Intent intent = new Intent(this,SecondActivity.class);
        startActivity(intent);
    }
}

MainActivity

3、获取文件的流，并读取文件

public class SecondActivity extends Activity {
    private static final String TAG = "SecondActivity";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);
        try {
            FileInputStream stream = openFileInput("serialiable");
            ObjectInputStream ois = new ObjectInputStream(stream);
            Book book = (Book) ois.readObject();
            Log.d(TAG,book+"");
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (StreamCorruptedException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
}

SecondActivity

Parcelable的使用

步骤：1.创建Book类，并继承Parcelable  2、重写Parcelable的接口  3、创建Creator

详细步骤：

public class Book implements Parcelable {
    private String name;
    private String author;
    private String publish;

    public Book(String author, String name, String publish) {
        this.author = author;
        this.name = name;
        this.publish = publish;
    }

    public Book(Parcel parcel){
        this.author = parcel.readString();
        this.name = parcel.readString();
        this.publish = parcel.readString();
    }

    @Override
    public String toString() {
        return "Book{" +
                "author='" + author + '\'' +
                ", name='" + name + '\'' +
                ", publish='" + publish + '\'' +
                '}';
    }

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

    @Override
    public void writeToParcel(Parcel dest, int flags) {
    }
}

Book

②、重写writeToParcel()

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

Book

③、创建获取器Creator

    public Book(Parcel parcel){
        this.author = parcel.readString();
        this.name = parcel.readString();
        this.publish = parcel.readString();
    }

    public static final Parcelable.Creator<Book> CREATOR = new Parcelable.Creator<Book>(){
        @Override
        public Book createFromParcel(Parcel source) {
            return new Book(source);
        }

        @Override
        public Book[] newArray(int size) {
            return new Book[0];
        }
    };

Book

完整代码

public class Book implements Parcelable {
    private String name;
    private String author;
    private String publish;

    public Book(String author, String name, String publish) {
        this.author = author;
        this.name = name;
        this.publish = publish;
    }

    @Override
    public String toString() {
        return "Book{" +
                "author='" + author + '\'' +
                ", name='" + name + '\'' +
                ", publish='" + publish + '\'' +
                '}';
    }

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

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

    public Book(Parcel parcel){
        this.author = parcel.readString();
        this.name = parcel.readString();
        this.publish = parcel.readString();
    }

    public static final Parcelable.Creator<Book> CREATOR = new Parcelable.Creator<Book>(){
        @Override
        public Book createFromParcel(Parcel source) {
            return new Book(source);
        }

        @Override
        public Book[] newArray(int size) {
            return new Book[0];
        }
    };
}

Book

IPC的简单使用：

任务：完成多进程间Book的添加和获取

步骤1、在java文件夹下创建aidl文件夹（需要进行IPC的文件都放在这个地方）

步骤2、在aidl文件夹下创建Book，并继承Parcelable

(1)、创建Book类

public class Book {
    private String author;
    private String name;
    private String publish;

    public Book(String author, String name, String publish) {
        this.author = author;
        this.name = name;
        this.publish = publish;
    }

    @Override
    public String toString() {
        return "Book{" +
                "author='" + author + '\'' +
                ", name='" + name + '\'' +
                ", publish='" + publish + '\'' +
                '}';
    }
}

Book

(2)、继承Parcelable

public class Book implements Parcelable{
    private String author;
    private String name;
    private String publish;

    public Book(String author, String name, String publish) {
        this.author = author;
        this.name = name;
        this.publish = publish;
    }

    @Override
    public String toString() {
        return "Book{" +
                "author='" + author + '\'' +
                ", name='" + name + '\'' +
                ", publish='" + publish + '\'' +
                '}';
    }
    //不用修改
    @Override
    public int describeContents() {
        return 0;
    }

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

    public static Parcelable.Creator<Book> CREATOR = new Parcelable.Creator<Book>(){

        @Override
        public Book createFromParcel(Parcel source) {
            return new Book(source);
        }

        @Override
        public Book[] newArray(int size) {
            return new Book[0];
        }
    };
    //读取的顺序跟保存的顺序需要一致
    public Book(Parcel parcel){
        author = parcel.readString();
        name = parcel.readString();
        publish = parcel.readString();
    }
}

Book

步骤3、在aidl文件夹中声明Book(只有在aidl声明的类才能在aidl中调用)，会生成src/main下的aidl文件夹

package aidl;
// Declare any non-default types here with import statements
parcelable Book;

Book.aidl

步骤4、在src/main/aidl文件夹中创建IBookManager

// IBookManager.aidl
package aidl;
//需要自己添加import声明
import aidl.Book;
// Declare any non-default types here with import statements
interface IBookManager {
    //注意：需要填写in out inout 参数的类型
    void addBook(in Book book);
    List getBook();
}

IBookManager.aidl

步骤5、创建Service，并实现Binder（IBookManager）

public class BookManagerService extends Service{
    private static final String TAG = "BookManagerService";
    private List<Book> mBookItems;

    @Override
    public void onCreate() {
        super.onCreate();
        mBookItems = new ArrayList<>();
    }

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return new IBookManager.Stub(){
            @Override
            public void addBook(Book book) throws RemoteException {
                mBookItems.add(book);
                Log.d(TAG,book+"  ");
            }

            @Override
            public List getBook() throws RemoteException {
                return mBookItems;
            }
        };
    }
}

BookManagerService

步骤6、测试,Binder死亡时候重新创建的使用

public class MainActivity extends AppCompatActivity {
    private IBookManager manager;
    private ServiceConnection connection;
    //当Binder被以外终止的时候调用
    private IBinder.DeathRecipient deathRecipient = new IBinder.DeathRecipient() {
        @Override
        public void binderDied() {
            if (manager != null){
                manager.asBinder().unlinkToDeath(deathRecipient,0);
                manager = null;
            }
            //接下来重新binderService
            createService();
            Intent intent = new Intent(MainActivity.this, BookManagerService.class);
            bindService(intent,connection, Service.BIND_AUTO_CREATE);
        }
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        createService();
    }

    private void createService() {
        connection = new ServiceConnection() {
            @Override
            public void onServiceConnected(ComponentName name, IBinder service) {
                manager = IBookManager.Stub.asInterface(service);
                Book book = new Book("asd","zxc","qweqw");
                try {
                    manager.addBook(book);
                } catch (RemoteException e) {
                    e.printStackTrace();
                }
                try {
                    //绑定死亡接口
                    service.linkToDeath(deathRecipient, 0);
                } catch (RemoteException e) {
                    e.printStackTrace();
                }
            }

            @Override
            public void onServiceDisconnected(ComponentName name) {
                //以外终止时候调用
            }
        };
    }

    public void launchSecondActivity(View view){
        Intent intent = new Intent(this, BookManagerService.class);
        bindService(intent,connection, Service.BIND_AUTO_CREATE);
    }
}

MainActivity