java-多线程回调方法

概述我的应用程序中有一个服务,该服务使客户端可以注册以接收来自该服务的回调.我尝试实现它,以便在调用客户端回调实现时,它们可以异步运行或在服务线程上按顺序运行.每个回调的具体行为取决于使用哪种方法注册客户端以进行回调.客户端可以向registerClientForCallbacks注册以使回调发

我的应用程序中有一个服务,该服务使客户端可以注册以接收来自该服务的回调.我尝试实现它,以便在调用客户端回调实现时,它们可以异步运行或在服务线程上按顺序运行.每个回调的具体行为取决于使用哪种方法注册客户端以进行回调.客户端可以向registerClIEntForCallbacks注册以使回调发生在主线程上,也可以向registerClIEntForAsyncCallbacks注册以使回调发生在新线程上.

我遇到的问题是,当我尝试在新线程上调用回调时,线程在thread.run()上阻塞,直到可运行项完成为止,从而有效地消除了我对多线程的尝试.我已经在下面发布了我的服务的代码(使用Javadoc,因为我知道它的时间很长).有人可以帮我理解为什么callAllRegisteredClIEnts中的线程无法同时运行吗？

public class ExampleService extends Service {    /**     * A record of the clIEnts which have registered to receive callbacks from this service     * asynchronously.     */    private Set<ClIEntCallbacks> registeredClIEntsAsync;    /**     * A record of the clIEnts which have registered to receive callbacks from this service on the     * service's main thread.     */    private Set<ClIEntCallbacks> registeredClIEntsMainThread;    @OverrIDe    public voID onCreate() {        super.onCreate();        registeredClIEntsAsync = new HashSet<ClIEntCallbacks>();        registeredClIEntsMainThread = new HashSet<ClIEntCallbacks>();    }    @OverrIDe    public IBinder onBind(Intent intent) {        return new LocalBinder();    }    /**     * A binder with the singular purpose of returning a reference to the service.     */    public class LocalBinder extends Binder {        public ExampleService getService() {            return ExampleService.this;        }    }    /**     * Register this clIEnt to receive callback events from this service. Callback methods will     * execute sequentially on the service's main thread. ConsIDer using {@link     * #registerClIEntForAsyncCallbacks(ClIEntCallbacks) registerClIEntForAsyncCallbacks} for     * asynchronous callbacks.     *     * @param clIEnt the clIEnt to register, not null     * @return true if the clIEnt is unregistered or has been     * registered to receive callbacks asynchronously using {@link     * #registerClIEntForAsyncCallbacks(ClIEntCallbacks) registerClIEntForAsyncCallbacks}, false     * otherwise     */    public boolean registerClIEntForCallbacks(@NonNull ClIEntCallbacks clIEnt) {        if (clIEnt == null) {            throw new IllegalArgumentException("clIEnt cannot be null");        }        // Attempt to remove from async callbacks set (may do nothing)        registeredClIEntsAsync.remove(clIEnt);        return registeredClIEntsMainThread.add(clIEnt);    }    /**     * Register this clIEnt to receive callback events from this service. Callback methods will be     * executed asynchronously on separate threads.     *     * @param clIEnt the clIEnt to register, not null     * @return true if the clIEnt is unregistered or has been     * registered to receive callbacks in the service's main thread using {@link     * #registerClIEntForCallbacks(ClIEntCallbacks) registerClIEntForCallbacks}, false     * otherwise     */    public boolean registerClIEntForAsyncCallbacks(@NonNull ClIEntCallbacks clIEnt) {        if (clIEnt == null) {            throw new IllegalArgumentException("clIEnt cannot be null");        }        // Attempt to remove from async callbacks set (may do nothing)        registeredClIEntsMainThread.remove(clIEnt);        return registeredClIEntsAsync.add(clIEnt);    }    /**     * Calls the {@link #ClIEntCallbacks ClIEntCallbacks} callback methods in all registered     * clIEnts. ClIEnts registered for asynchronous callbacks will execute immediately, and     * clIEnts registered for sequential callbacks will be called in turn. Note that if the     * callback methods block, then the service's main thread will block.     */    private voID callAllRegisteredClIEnts() {        // First start asynchronous callbacks        for (ClIEntCallbacks clIEnt : registeredClIEntsAsync) {            Thread t = new Thread(new CallbackRunnable(clIEnt), clIEnt.toString());            t.run();        }        // Finally start sequential callbacks        for (ClIEntCallbacks clIEnt : registeredClIEntsMainThread) {            clIEnt.onServiceEvent(this);        }    }    /**     * Interface allows callback events to be delivered to registered server clIEnts.     */    public interface ClIEntCallbacks {        public voID onServiceEvent(Service service);    }    /**     * A utility class which allows clIEnt callback methods to be executed asynchronously.     */    private class CallbackRunnable implements Runnable {        /**         * The clIEnt to receive the callbacks.         */        private final ClIEntCallbacks clIEnt;        /**         * Creates a new CallbackRunnable.         * @param clIEnt the clIEnt to receive the callback methods, not null         */        private CallbackRunnable(@NonNull ClIEntCallbacks clIEnt) {            if (clIEnt == null) {                throw new IllegalArgumentException("clIEnt cannot be null");            }            this.clIEnt = clIEnt;        }        @OverrIDe        public voID run() {            androID.os.Process.setThreadPriority(Process.THREAD_PRIORITY_DEFAulT);            clIEnt.onServiceEvent(ExampleService.this);        }    }    /*     * Testing     * Todo remove     */    public voID activateCallbacks() {        callAllRegisteredClIEnts();    }}

解决方法:

您必须使用t.start()而不是t.run().

t.run()直接调用可运行对象的run()方法. t.start()启动一个新线程,然后调用run()方法.

另外,您应该考虑使用Executor而不是直接创建和启动线程…

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