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/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
#ifndef _ANDROID_NATIVE_APP_GLUE_H
#define _ANDROID_NATIVE_APP_GLUE_H
#include <poll.h>
#include <pthread.h>
#include <sched.h>
#include <android/native_activity.h>
#include <android/looper.h>
#ifdef __cplusplus
extern "C"
#endif
/**
* The native activity interface provided by <android/native_activity.h>
* is based on a set of application-provided callbacks that will be called
* by the Activity's main thread when certain events occur.
*
* This means that each one of this callbacks _should_ _not_ block, or they
* risk having the system force-close the application. This programming
* model is direct, lightweight, but constraining.
*
* The 'threaded_native_app' static library is used to provide a different
* execution model where the application can implement its own main event
* loop in a different thread instead. Here's how it works:
*
* 1/ The application must provide a function named "android_main()" that
* will be called when the activity is created, in a new thread that is
* distinct from the activity's main thread.
*
* 2/ android_main() receives a pointer to a valid "android_app" structure
* that contains references to other important objects, e.g. the
* ANativeActivity obejct instance the application is running in.
*
* 3/ the "android_app" object holds an ALooper instance that already
* listens to two important things:
*
* - activity lifecycle events (e.g. "pause", "resume"). See APP_CMD_XXX
* declarations below.
*
* - input events coming from the AInputQueue attached to the activity.
*
* Each of these correspond to an ALooper callback that returns a "data"
* value of LOOPER_ID_MAIN and LOOPER_ID_EVENT, respectively.
*
* Your application can use the same ALooper to listen to additionnal
* file-descriptors.
*
* 4/ Whenever you receive a LOOPER_ID_MAIN event from the ALooper, your
* code should call the function android_app_read_cmd() to read the
* command value and act upon it. This is normally done by calling
* android_app_exec_cmd() directly.
*
* XXX: MAKE THIS STUFF MORE CLEAR !!
*
* 5/ Whenever you receive a LOOPER_ID_EVENT event from the ALooper, you
* should read one event from the AInputQueue with AInputQueue_getEvent().
*
* See the sample named "native-activity" that comes with the NDK with a
* full usage example.
*
*/
/**
* This is the interface for the standard glue code of a threaded
* application. In this model, the application's code is running
* in its own thread separate from the main thread of the process.
* It is not required that this thread be associated with the Java
* VM, although it will need to be in order to make JNI calls any
* Java objects.
*/
struct android_app {
// The application can place a pointer to its own state object
// here if it likes.
void* userData;
// The ANativeActivity object instance that this app is running in.
ANativeActivity* activity;
// The ALooper associated with the app's thread.
ALooper* looper;
// When non-NULL, this is the input queue from which the app will
// receive user input events.
AInputQueue* inputQueue;
// When non-NULL, this is the window surface that the app can draw in.
ANativeWindow* window;
// Current content rectangle of the window; this is the area where the
// window's content should be placed to be seen by the user.
ARect contentRect;
// Current state of the app's activity. May be either APP_CMD_START,
// APP_CMD_RESUME, APP_CMD_PAUSE, or APP_CMD_STOP; see below.
int activityState;
// -------------------------------------------------
// Below are "private" implementation of the glue code.
pthread_mutex_t mutex;
pthread_cond_t cond;
int msgread;
int msgwrite;
pthread_t thread;
// This is non-zero when the application's NativeActivity is being
// destroyed and waiting for the app thread to complete.
int destroyRequested;
int running;
int destroyed;
int redrawNeeded;
AInputQueue* pendingInputQueue;
ANativeWindow* pendingWindow;
ARect pendingContentRect;
};
enum {
/**
* Looper data ID of commands coming from the app's main thread.
* These can be retrieved and processed with android_app_read_cmd()
* and android_app_exec_cmd().
*/
LOOPER_ID_MAIN = 1,
/**
* Looper data ID of events coming from the AInputQueue of the
* application's window. These can be read via the inputQueue
* object of android_app.
*/
LOOPER_ID_EVENT = 2
};
enum {
/**
* Command from main thread: the AInputQueue has changed. Upon processing
* this command, android_app->inputQueue will be updated to the new queue
* (or NULL).
*/
APP_CMD_INPUT_CHANGED,
/**
* Command from main thread: the ANativeWindow has changed. Upon processing
* this command, android_app->window will be updated to the new window surface
* (or NULL).
*/
APP_CMD_WINDOW_CHANGED,
/**
* Command from main thread: the current ANativeWindow has been resized.
* Please redraw with its new size.
*/
APP_CMD_WINDOW_RESIZED,
/**
* Command from main thread: the system needs that the current ANativeWindow
* be redrawn. You should redraw the window before handing this to
* android_app_exec_cmd() in order to avoid transient drawing glitches.
*/
APP_CMD_WINDOW_REDRAW_NEEDED,
/**
* Command from main thread: the content area of the window has changed,
* such as from the soft input window being shown or hidden. You can
* find the new content rect in android_app::contentRect.
*/
APP_CMD_CONTENT_RECT_CHANGED,
/**
* Command from main thread: the app's activity window has gained
* input focus.
*/
APP_CMD_GAINED_FOCUS,
/**
* Command from main thread: the app's activity window has lost
* input focus.
*/
APP_CMD_LOST_FOCUS,
/**
* Command from main thread: the system is running low on memory.
* Try to reduce your memory use.
*/
APP_CMD_LOW_MEMORY,
/**
* Command from main thread: the app's activity has been started.
*/
APP_CMD_START,
/**
* Command from main thread: the app's activity has been resumed.
*/
APP_CMD_RESUME,
/**
* Command from main thread: the app's activity has been paused.
*/
APP_CMD_PAUSE,
/**
* Command from main thread: the app's activity has been stopped.
*/
APP_CMD_STOP,
/**
* Command from main thread: the app's activity is being destroyed,
* and waiting for the app thread to clean up and exit before proceeding.
*/
APP_CMD_DESTROY,
};
/**
* Call when ALooper_pollAll() returns LOOPER_ID_MAIN, reading the next
* app command message.
*/
int8_t android_app_read_cmd(struct android_app* android_app);
/**
* Call with the command returned by android_app_read_cmd() to do the
* default processing of the given command.
*
* Important: returns 0 if the app should exit. You must ALWAYS check for
* a zero return and, if found, exit your android_main() function.
*/
int32_t android_app_exec_cmd(struct android_app* android_app, int8_t cmd);
/**
* This is the function that application code must implement, representing
* the main entry to the app.
*/
extern void android_main(struct android_app* app);
#ifdef __cplusplus
}
#endif
#endif /* _ANDROID_NATIVE_APP_GLUE_H */