App.h

00001 /*
00002  *  Copyright 2014 Embedded Artists AB
00003  *
00004  *  Licensed under the Apache License, Version 2.0 (the "License");
00005  *  you may not use this file except in compliance with the License.
00006  *  You may obtain a copy of the License at
00007  *
00008  *    http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  *  Unless required by applicable law or agreed to in writing, software
00011  *  distributed under the License is distributed on an "AS IS" BASIS,
00012  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  *  See the License for the specific language governing permissions and
00014  *  limitations under the License.
00015  */
00016 
00017 #ifndef APP_H
00018 #define APP_H
00019 
00020 /**
00021  * Base class for all Apps. The idea is that you can have multiple
00022  * Apps in your program. Each App has three funtions:
00023  *
00024  *  setup() is called to let the App load all needed resources
00025  *
00026  *  runToCompletion() is called and will not return until the App exits
00027  *
00028  *  teardown() is called to let the App free allocated resources
00029  *
00030  * For an example of Apps in use, see the AppLauncher class
00031  */
00032 class App {
00033 public:
00034     virtual ~App() {};
00035 
00036     /** Prepare the App before it is started.
00037      *
00038      *  This function can be implemented to allocate memory, load startup
00039      *  images or other time consuming preparations.
00040      *
00041      *  The return value is to let the caller now if the application can
00042      *  be started or not.
00043      *
00044      *  @param x       the touched x coordinate
00045      *  @param y       the touched y coordinate
00046      *  @param pressed true if the user pressed the display
00047      *
00048      *  @returns
00049      *       true if the app can be started
00050      *       false if the setup failed
00051      */
00052     virtual bool setup() { return true; }
00053     
00054     /** Runs the App to completion
00055      *
00056      *  This function should not return until the App has finished.
00057      */
00058     virtual void runToCompletion() = 0;
00059     
00060     /** Cleanup
00061      *
00062      *  Implement to free up the memory allocated in setup().
00063      *
00064      *  @returns
00065      *       true if the teardown finished successfully
00066      *       false if the teardown failed
00067      */
00068     virtual bool teardown() { return true; }
00069 };
00070 
00071 #endif