android AIDL 语言用法

Posted 2020-10-23 Arcturis

跨进程通信可以用AIDL语言

这里讲述下如何使用AIDL语言进行跨进程通信

文章参考 《设计模式》一书

demo结构参考

主要的文件类有：IBankAidl.aidl

java文件：AidlBankBinder，BackActivity（应该是BankActivity写错了），BankService（继承自Service，服务类）

IBankAidl.aidl文件 这里AIdl的使用对包位置有要求，所以我就把包名放出来了

package finishdemo.arcturis.binderandserviceandaidl.binder;

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

interface IBankAidl {
    /**
     * Demonstrates some basic types that you can use as parameters
     * and return values in AIDL.
     */
    void basicTypes(int anInt, long aLong, boolean aBoolean, float aFloat,
            double aDouble, String aString);
   /**
     * 开户
     * @param name 户主名
     * @param password 密码
     * @return 开户信息
     */
    String openAccount(String name,String password);

    /**
     * 存钱
     * @param money
     * @param account
     * @return
     */
    String saveMoney(int money,String account);

    /**
     * 取钱
     * @param money
     * @param account
     * @param password
     * @return
     */
    String takeMoney(int money,String account,String password);

    /**
     * 销户
     * @param account
     * @param password
     * @return
     */
    String closeAccount(String account,String password);

}

AidlBankBinder文件 继承自IBankAidl的Stub类，然后重写并实现Aidl内的方法，这里是模拟一个银行的操作

public class AidlBankBinder extends IBankAidl.Stub {

    @Override
    public void basicTypes(int anInt, long aLong, boolean aBoolean, float aFloat, double aDouble, String aString) throws RemoteException {
    }

    @Override
    public String openAccount(String name, String password) {
        return name+"开户成功！账号为："+ UUID.randomUUID().toString();
    }

    @Override
    public String saveMoney(int money, String account) {
        return "账户:"+account + "存入"+ money + "单位:人民币";
    }

    @Override
    public String takeMoney(int money, String account, String password) {
        return "账户:"+account + "支取"+ money + "单位:人民币";
    }

    @Override
    public String closeAccount(String account, String password) {
        return account + "销户成功";
    }
}

BankService文件 返回一个AidlBankBinder 

public class BankService extends Service {

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        //单进程写法
//        return new BankBinder();
        //不同进程AIDL 通信写法
        return new AidlBankBinder();
    }
}

接下来在Activity中使用 BackActivity方法

public class BackActivity extends AppCompatActivity implements View.OnClickListener {

//    private BankBinder mBankBinder;
    private IBankAidl mBankBinder;

    private TextView tvMsg;

    private Context context;


    private ServiceConnection conn = new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            //同一进程写法
//            mBankBinder = (BankBinder) service;
            //不同进程写法
            mBankBinder = IBankAidl.Stub.asInterface(service);
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {

        }
    };


    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        context = this;
        tvMsg = (TextView) findViewById(R.id.tv_msg);

        Intent intent = new Intent();
        intent.setAction("actionname.aidl.bank.BankService");

        //这里遇到一个问题，如果你直接使用intent 这个意图去开启服务的话就会报
        //android Service Intent must be explicit 意思是服务必须要显示的调用，这个是5.0之后新的规定
        //这个 createExplicitFromImplicitIntent 可以将隐性调用变成显性调用
        Intent intent1  = new Intent(createExplicitFromImplicitIntent(context,intent));

        bindService(intent1,conn,BIND_AUTO_CREATE);

        initBtn(R.id.btn_aidl_bank_close);
        initBtn(R.id.btn_aidl_bank_open);
        initBtn(R.id.btn_aidl_bank_save);
        initBtn(R.id.btn_aidl_bank_take);
    }

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

    private void initBtn(int resID){
        Button b = (Button) findViewById(resID);
        b.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.btn_aidl_bank_open:
                //这个RemoteException 是 AIDL跨进程通信的用法必须加上的异常捕获
                try {
                    tvMsg.setText(mBankBinder.openAccount("BigAss","123456"));
                }catch (RemoteException e){
                    e.printStackTrace();
                }
                break;

            case R.id.btn_aidl_bank_save:
                try {
                    tvMsg.setText(mBankBinder.saveMoney(8888888,"bigAss123"));
                }catch (RemoteException e){
                    e.printStackTrace();
                }
                break;

            case R.id.btn_aidl_bank_take:
                try {
                    tvMsg.setText(mBankBinder.takeMoney(520,"bigAss123","123456"));
                }catch (RemoteException e){
                    e.printStackTrace();
                }
                break;

            case R.id.btn_aidl_bank_close:
                try {
                    tvMsg.setText(mBankBinder.closeAccount("bigAss123","123456"));
                }catch (RemoteException e){
                    e.printStackTrace();
                }
                break;

        }
    }


    /***
     * Android L (lollipop, API 21) introduced a new problem when trying to invoke implicit intent,
     * "java.lang.IllegalArgumentException: Service Intent must be explicit"
     *
     * If you are using an implicit intent, and know only 1 target would answer this intent,
     * This method will help you turn the implicit intent into the explicit form.
     *
     * Inspired from SO answer: http://stackoverflow.com/a/26318757/1446466
     * @param context
     * @param implicitIntent - The original implicit intent
     * @return Explicit Intent created from the implicit original intent
     */
    public static Intent createExplicitFromImplicitIntent(Context context, Intent implicitIntent) {
        // Retrieve all services that can match the given intent
        PackageManager pm = context.getPackageManager();
        List<ResolveInfo> 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;
    }
}

主要思路是用隐式的方法启动一个服务，然后调用Aidl实例类的方法即可，具体的Aidl语言在BuildApp之后在

这里即可查看 内部是他实现进程间数据传输所做的转化代码，有兴趣可以看下