java - binder
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java binder是什麼,讓我們一起了解一下?
binder是基於c/s架構的,主要包括四個部分:服務端(Server),客戶端(Client),Binder驅動ServiceManager,四部分之間的交互都是透過Binder來實現的,而且java層binder架構實際上也是基於c/s架構的。
那麼binder機制在java層是如何使用的?
java層binder架構實際上也是基於c/s架構的,而且其在類的命名上也儘量與native層保持一致,因此可認爲java層的binder架構是native層binder架構的一個鏡像。
示例Binder類的初始化:
const char* const kBinderPathName = "android/os/Binder"; static int int_register_android_os_Binder(JNIEnv* env) {undefined jclass clazz = FindClassOrDie(env, kBinderPathName); gBinderOffsets.mClass = MakeGlobalRefOrDie(env, clazz); gBinderOffsets.mExecTransact = GetMethodIDOrDie(env, clazz, "execTransact", "(IJJI)Z"); gBinderOffsets.mObject = GetFieldIDOrDie(env, clazz, "mObject", "J"); return RegisterMethodsOrDie( env, kBinderPathName, gBinderMethods, NELEM(gBinderMethods)); }
也可以創建一個Service,在其onBind裏返回一個服務端Binder對象,在客戶端的ServiceConnection裏拿到這個Binder對象。
//服務端public class BinderPoolService extends Service {private static final String TAG = "BinderPoolService";private Binder mBinderPool = new BinderPool.BinderPoolImpl();@Nullable@Overridepublic IBinder onBind(Intent intent) {return mBinderPool;}}//客戶端private ServiceConnection mBinderPoolConnection = new ServiceConnection() {@Overridepublic void onServiceConnected(ComponentName name, IBinder service) {//拿到服務端返回的Binder接口mBinderPool = IBinderPool.Stub.asInterface(service);...}@Overridepublic void onServiceDisconnected(ComponentName name) {}};Intent intent = new Intent(mContext, BinderPoolService.class);mContext.bindService(intent, mBinderPoolConnection, Context.BIND_AUTO_CREATE);