如何正确使用 wait 和 notify 方法？

Question

我的异步调用有问题。我需要 "do" 循环来等待异步调用继续。但是当你运行方法 "lock.wait ()" 应用程序冻结并且异步调用不是 cales.

lock.wait();

应用程序已冻结，但未调用以下命令行且应用程序未继续执行以下方法：

callUser.enqueue(new Callback<BaseResponse<User>>() {
    @Override
    public void onResponse(Response<BaseResponse<User>> response, Retrofit retrofit) {
        updateUsersFromServer(response.body());
    }

    @Override
    public void onFailure(Throwable t) {
        UserEvent UserEvent = new UserEvent(
                null, 500, R.string.order_unavailable);
        EventBus.getDefault().post(UserEvent);
    }
});

我需要更好地了解 "wait ()" 方法是什么样的。

如何让应用程序在"wait ()"方法中不停止？

public void fetchUser(Integer cdCode, String pinckingListNumber) {
    List<User> Users = new ArrayList<>();
    do {
        fetchUserApi(cdCode, pinckingListNumber);
        synchronized (lock) {
            try {
                lock.wait();
            } catch (InterruptedException e) {
                callUser = false;
                UserEvent UserEvent = new UserEvent(
                        null, 500, R.string.order_unavailable);
                EventBus.getDefault().post(UserEvent);
            }
        }
        offset = offset + 10;
        if (!ObjectValidation.isEmptyOrNull(response)) {
            for (int i = 0; i < response.getRecords().size(); i++) {
                Users.add(response.getRecords().get(i));
            }
            if (response.getMeta().getRecordCount() < response.getMeta().getOffset())
                callUser = false;
        } else {
            callUser = false;
            UserEvent UserEvent = new UserEvent(
                    null, 500, R.string.order_unavailable);
            EventBus.getDefault().post(UserEvent);
        }
        try {
            Thread.sleep(3000);
        } catch (InterruptedException e) {
            callUser = false;
            UserEvent UserEvent = new UserEvent(
                    null, 500, R.string.order_unavailable);
            EventBus.getDefault().post(UserEvent);
        }
    } while (callUser);

    UserEvent UserEvent = new UserEvent(
            Users, 200, R.string.delivery_success);
    EventBus.getDefault().post(UserEvent);
}

private void fetchUserApi(Integer cdCode, String pinckingListNumber) {
    UserResource UserResource = getRetrofit().create(UserResource.class);
    Call<BaseResponse<User>> callUser = UserResource.getListUsers(
            authController.getTokenHeader(),
            pinckingListNumber,
            cdCode,
            limit,
            offset
    );

    callUser.enqueue(new Callback<BaseResponse<User>>() {
        @Override
        public void onResponse(Response<BaseResponse<User>> response, Retrofit retrofit) {
            updateUsersFromServer(response.body());
        }

        @Override
        public void onFailure(Throwable t) {
            UserEvent UserEvent = new UserEvent(
                    null, 500, R.string.order_unavailable);
            EventBus.getDefault().post(UserEvent);
        }
    });
}

private void updateUsersFromServer(BaseResponse<User> baseResponseUsers) {
    synchronized (lock) {
        response = baseResponseUsers;
        lock.notify();
    }
}

Answer 1

在应用程序的情况下我不能使用Retrofit 异步方法。不知道是不是retrofit的bug，但是当我使用retrofit异步方法执行Wait()命令时，应用卡住了。

所以我不得不创建改造的同步方法，然后使用线程，这样我就可以在应用程序不冻结的情况下使用等待和通知方法。

public void fetchUser(Integer cdCode, String pinckingListNumber) {
     List<User> Users = new ArrayList<>();
        do {
            fetchUserApi(cdCode, pinckingListNumber);
            // My code modification
            synchronized (thread) {
                try {
                    thread.wait();
                } catch (InterruptedException e) {
                    callUser = false;
                    UserEvent UserEvent = new UserEvent(
                            null, 500, R.string.order_unavailable);
                    EventBus.getDefault().post(UserEvent);
                }
            }
            offset = offset + 10;
            if (!ObjectValidation.isEmptyOrNull(response)) {
                for (int i = 0; i < response.getRecords().size(); i++) {
                    Users.add(response.getRecords().get(i));
                }
                if (response.getMeta().getRecordCount() < response.getMeta().getOffset())
                    callUser = false;
            } else {
                callUser = false;
                UserEvent UserEvent = new UserEvent(
                        null, 500, R.string.order_unavailable);
                EventBus.getDefault().post(UserEvent);
            }
            try {
                Thread.sleep(3000);
            } catch (InterruptedException e) {
                callUser = false;
                UserEvent UserEvent = new UserEvent(
                        null, 500, R.string.order_unavailable);
                EventBus.getDefault().post(UserEvent);
            }
        } while (callUser);

        UserEvent UserEvent = new UserEvent(
                Users, 200, R.string.delivery_success);
        EventBus.getDefault().post(UserEvent);
    }

    private void fetchUserApi(Integer cdCode, String pinckingListNumber) {
        UserResource userResource = getRetrofit().create(UserResource.class);
        final Call<BaseResponse<User>> callUserAPI = userResource.getListUsers(
                    authController.getTokenHeader(),
                    pinckingListNumber,
                    cdCode,
                    limit,
                    offset
            );
            // My code modification
            thread = new Thread(new Runnable() {
                @Override
                public void run() {
                    try {
                        updateUsersFromServer(callUserAPI.execute().body());
                        synchronized (thread) {
                            thread.notify();
                        }
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            });

            thread.start();
    }
    private void updateUsersFromServer(BaseResponse<User> baseResponseUsers) {
            response = baseResponseUsers;
        }

如何正确使用 wait 和 notify 方法？

How to use the wait and notify methods correctly?

java

android

asynchronous

threadpool

async-await