1// Copyright 2014 The Chromium Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style license that can be 3// found in the LICENSE file. 4 5#ifndef BASE_ANDROID_APPLICATION_STATUS_LISTENER_H_ 6#define BASE_ANDROID_APPLICATION_STATUS_LISTENER_H_ 7 8#include <jni.h> 9 10#include "base/android/jni_android.h" 11#include "base/base_export.h" 12#include "base/basictypes.h" 13#include "base/memory/ref_counted.h" 14#include "base/memory/singleton.h" 15#include "base/observer_list_threadsafe.h" 16 17namespace base { 18namespace android { 19 20// Define application state values like APPLICATION_STATE_VISIBLE in a 21// way that ensures they're always the same than their Java counterpart. 22enum ApplicationState { 23#define DEFINE_APPLICATION_STATE(x, y) APPLICATION_STATE_##x = y, 24#include "base/android/application_state_list.h" 25#undef DEFINE_APPLICATION_STATE 26}; 27 28// A native helper class to listen to state changes of the Android 29// Application. This mirrors org.chromium.base.ApplicationStatus. 30// any thread. 31// 32// To start listening, create a new instance, passing a callback to a 33// function that takes an ApplicationState parameter. To stop listening, 34// simply delete the listener object. The implementation guarantees 35// that the callback will always be called on the thread that created 36// the listener. 37// 38// Example: 39// 40// void OnApplicationStateChange(ApplicationState state) { 41// ... 42// } 43// 44// // Start listening. 45// ApplicationStatusListener* my_listener = 46// new ApplicationStatusListener( 47// base::Bind(&OnApplicationStateChange)); 48// 49// ... 50// 51// // Stop listening. 52// delete my_listener 53// 54class BASE_EXPORT ApplicationStatusListener { 55 public: 56 typedef base::Callback<void(ApplicationState)> ApplicationStateChangeCallback; 57 58 explicit ApplicationStatusListener( 59 const ApplicationStateChangeCallback& callback); 60 ~ApplicationStatusListener(); 61 62 // Internal use: must be public to be called from base_jni_registrar.cc 63 static bool RegisterBindings(JNIEnv* env); 64 65 // Internal use only: must be public to be called from JNI and unit tests. 66 static void NotifyApplicationStateChange(ApplicationState state); 67 68 private: 69 void Notify(ApplicationState state); 70 71 ApplicationStateChangeCallback callback_; 72 73 DISALLOW_COPY_AND_ASSIGN(ApplicationStatusListener); 74}; 75 76} // namespace android 77} // namespace base 78 79#endif // BASE_ANDROID_APPLICATION_STATUS_LISTENER_H_ 80