ウチで使ってるのの劣化版

// Canvas#processEvent で呼び出す
public static void processEvent( int type, int param ) {
if( type == Display.KEY_PRESSED_EVENT ) {
keyDown |= 1 << param;
lastKeyDown = keyDown;
}
}

// メインループで呼び出す
public static void update() {
MyCanvas canvas = ( (MyApp) IApplication.getCurrentApp() ).canvas;
keyArea = keyDown | canvas.getKeypadState();
keyUp = lastKeyArea & ( ~keyArea );
lastKeyArea = keyArea;
keyDown = 0;
}
// ボタンアップ時にtrue
public static boolean isKeyUp( int key ) {
return ( keyUp & key ) == key;
}
// ボタンダウン時にtrue
public static boolean isKeyDown( int key ) {
return ( keyDown & key ) == key;
}
// ボタン押しっぱでtrue
public static boolean isKeyArea( int key ) {
return ( keyArea & key ) == key;
}