Motorola C450, C550, C370 technical manual Using GameScreen

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Gaming API and Sound

•public void playBackgroundMusic (BackgroundMusic bgm, boolean loop) - Plays the specified BackgroundMusic object from the beginning. This method first stops the current BackgroundMusic if any. Thus, this method may be used to start background music (by specifying a non-null BackgroundMusic object), restart the current background music (by specifying the same BackgroundMusic object), change the background music, or end the background music (by specifying null). The loop parameter is set to true if the BackgroundMusic is to repeat indefinitely. Otherwise, set to false.

Using GameScreen

The GameDemoScreen class uses the GameScreen class to provide a UI screen for a hypothetic game. GameDemoScreen is a subclass of GameScreen that implements runnable for running the main game loop thread.

The following code sample shows implementation of using GameScreen.

GameScreen

class GameDemoScreen extends GameScreen implements Runnable{

// ...

public void run() {

//Get the Graphics object for the

//off-screen buffer

Graphics g = getGraphics(); while (true) {

//Check user input and update

//positions if necessary

int keyState = getKeyStates(); if ((keyState & LEFT_KEY) != 0) {

sprite.move(-1, 0);

}

else if ((keyState & RIGHT_KEY) != 0) { sprite.move(1, 0);

}

//Draw the background g.drawImage(backgroundImage,0,0, Graphics.TOP

+Graphics.LEFT);

//Draw the sprite on top of the background sprite.draw(g);

//Flush the off-screen buffer flushGraphics();

}

}

// ...

}

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