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 17 namespace base { 18 namespace 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. 22 enum 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 // 54 class 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
