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基于Binder的4种RPC调用

news 2025/10/6 13:22:41

基于Binder的4种RPC调用 - Wesley’s Blog

基于Binder的4种RPC调用一般有AIDL、Messenger、借助 intent 传递 messenger 和基于 contentprovider 的 call

AIDL 和Messenger 比较常见了，可以参考：绑定服务概览 | Background work | Android Developers

这里只讨论后面两种情况，代码链接：https://github.com/wesley666/BinderRPC

借助 intent 传递 messenger

应用场景：比如授权弹窗需要借助另外一个进程或者组件完成，比如小米 adb 安装应用时的弹窗，安装流程是 system_server 完成的，但安全校验弹窗是安全中心负责的，方便解耦。

class Test {companion object {private const val TAG = "TestIntentRPC"}fun testServer(context: Context) {val messenger = TestMessenger()val intent = Intent()intent.`package` = context.packageNameintent.action = "android.intent.action.AUTHORIZE"val bundle = Bundle().apply {putValue(MESSENGER_KEY, messenger)}intent.apply {addFlags(Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_SINGLE_TOP)putExtra(ACTIVITY_INTENT_KEY, bundle)}context.startActivity(intent)synchronized(messenger.lock) {while (!messenger.finished) {try {messenger.lock.wait(10 * 1000L)messenger.finished = true} catch (e: InterruptedException) {e.printStackTrace()}}}Log.e(TAG, "testServer messenger.result: ${messenger.result}")}fun testClient(intent: Intent?) {var iBinder: IBinder? = nullvar messenger: IMessenger? = nullintent?.getBundleExtra(ACTIVITY_INTENT_KEY)?.apply {iBinder = getBinderValue(MESSENGER_KEY)}iBinder?.let {messenger = IMessenger.Stub.asInterface(it)}messenger?.let {val message = Message()message.what = 99it.send(message)}}private inner class TestMessenger : IMessenger.Stub() {@Volatilevar finished: Boolean = falsevar result: Int = 0val lock = Object()@SuppressLint("RethrowRemoteException", "VisiblySynchronized", "MissingNullability")@Throws(RemoteException::class)override fun send(message: Message) {synchronized(lock) {Log.i(TAG, "onAuthCheck send result: ${message.what}")this.finished = truethis.result = message.whatlock.notifyAll()}}}
}

framework 的代码可以借助IMessenger.Stub，app的代码可以自定义IMessenger

@SuppressLint({"RawAidl", "CallbackMethodName", "MissingNullability", "RethrowRemoteException"})public static class TestCallback extends IMessenger.Stub {boolean finished;String msg;int result;@SuppressLint({"RethrowRemoteException", "VisiblySynchronized", "MissingNullability"})public void send(@NonNull Message message) throws RemoteException {synchronized (this) {this.finished = true;this.result = message.what;Bundle data = message.getData();if (data != null) {this.msg = data.getString("msg");}notifyAll();}}}

基于 contentprovider 的 call 方法

应用场景：比如需要同步 RPC 调用，aidl 是异步绑定的；新增或者删减方法更加方便，aidl 需要严格的方法定义顺序。

比如Settings.Secure.putInt()本质上就是利用了call方法进行rpc，可以参考：

frameworks/base/core/java/android/provider/Settings.java

frameworks/base/packages/SettingsProvider/src/com/android/providers/settings/SettingsProvider.java

定义服务端：contentprovider，call里面也可以增加鉴权等

    override fun call(method: String, arg: String?, extras: Bundle?): Bundle? {if (ProviderHelper.CALL_FUNCTION == method && extras != null && arg != null) {return funMap.callFun(arg, extras)}return super.call(method, arg, extras)}

服务端方法定义

class FunMap(private val context: Context) {private val functions: HashMap<String, (Bundle) -> Bundle?> = HashMap()init {init()}private fun init() {functions[MethodDef.SAY_HELLO] = { bundle ->Log.i(TAG, "say hello from ${bundle.getString(ProviderHelper.KEY_ONE)}")null}functions[MethodDef.GET_NAME] = lambda@{return@lambda Bundle().apply {putString(ProviderHelper.KEY_RET, context.packageName)}}}fun callFun(methodName: String, bundle: Bundle): Bundle {return functions[methodName]?.invoke(bundle) ?: Bundle()}companion object {private const val TAG = "ProviderFunMap"}
}

公共方法

object MethodDef {const val SAY_HELLO = "sayHello"const val GET_NAME = "getName"
}@SuppressLint("StaticFieldLeak")
class ProviderHelper(private val context: Context, private val uriPath: String) {companion object {const val KEY_ONE: String = "key_one"const val KEY_TWO: String = "key_two"const val KEY_THREE: String = "key_three"const val KEY_FOUR: String = "key_four"const val KEY_FIVE: String = "key_five"const val KEY_RET: String = "ret"const val CALL_FUNCTION: String = "callFunction"const val TAG: String = "ProviderHelper"}private val mContentResolver: ContentResolver? = context.contentResolverfun callFunction(methodName: String, bundle: Bundle): Bundle? {val client = getClient() ?: return Bundle().apply {Log.e(TAG, "callFunction $methodName: client is null")}return try {client.call(CALL_FUNCTION, methodName, bundle)} catch (e: Exception) {Bundle()} finally {//如果频繁调用，可独立成一个函数，避免每次都closeclient.release()}}fun setParams(obj: Any? = null,obj2: Any? = null,obj3: Any? = null,obj4: Any? = null,obj5: Any? = null): Bundle {val bundle = Bundle()putValue(bundle, KEY_ONE, obj)putValue(bundle, KEY_TWO, obj2)putValue(bundle, KEY_THREE, obj3)putValue(bundle, KEY_FOUR, obj4)putValue(bundle, KEY_FIVE, obj5)return bundle}private fun putValue(bundle: Bundle, key: String, obj: Any?) {if (obj == null) {return}bundle.putValue(key, obj)}private fun getClient(): ContentProviderClient? {val contentResolver = this.mContentResolver ?: return nullreturn contentResolver.acquireUnstableContentProviderClient(Uri.parse(this.uriPath))}
}

客户端

class TestProviderRPC(private val context: Context) {private val providerHelper =ProviderHelper(context, "content://${context.packageName}.rpc.provider")fun sayHello(str: String) {providerHelper.callFunction(MethodDef.SAY_HELLO, providerHelper.setParams(str))}fun getName(): String {val ret = providerHelper.callFunction(MethodDef.GET_NAME, providerHelper.setParams())return ret?.getString(ProviderHelper.KEY_RET) ?: ""}
}