Hey everyone I am still working on this libgdx project and I am trying to figure out the best way to change the screens to my game screen Now, when a button is clicked I need it to transition to the game screen. I have seen a few implementations extending the game class but I am not sure what the best approach from here is. If you see some code that could be improved please let me know.
Here is the main application class:
public class ConnectFourApplication implements ApplicationListener {
private Screen screen;
public static void main(String[] args) {
new LwjglApplication(new ConnectFourApplication(), "PennyPop", 1280, 720,
true);
}
@Override
public void create() {
screen = new MainScreen();
screen.show();
}
@Override
public void dispose() {
screen.hide();
screen.dispose();
}
/** Clears the screen with a white color */
private void clearWhite() {
Gdx.gl.glClearColor(1, 1, 1, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
}
@Override
public void pause() {
screen.pause();
}
@Override
public void render() {
clearWhite();
screen.render(Gdx.graphics.getDeltaTime());
}
@Override
public void resize(int width, int height) {
screen.resize(width, height);
}
@Override
public void resume() {
screen.resume();
}
}
public class MainScreen implements Screen {
private final Stage stage;
private final SpriteBatch spriteBatch;
//Parameter for drawing the buttons
private final BitmapFont font;
private final TextureAtlas buttons;
private final Button SFXButton;
private final Button APIButton;
private final Button GameButton;
private final Skin images;
//Parameter for Sound
private final com.badlogic.gdx.audio.Sound SFXClick;
//Parameter for the api call
private final String WeatherUrl;
private final HttpRequest request;
private final City SanFrancisco;
//The screen to load after the game button is hit
private Screen gamescreen;
public MainScreen() {
//Set up our assets
spriteBatch = new SpriteBatch();
stage = new Stage(Gdx.graphics.getWidth(), Gdx.graphics.getHeight(), false, spriteBatch);
font = new BitmapFont(Gdx.files.internal("assets/font.fnt"),
Gdx.files.internal("assets/font.png"), false);
buttons = new TextureAtlas("assets/GameButtons.pack");
images = new Skin(buttons);
images.addRegions(buttons);
SFXButton = new Button(images.getDrawable("sfxButton"));
SFXButton.setPosition(295, 310);
APIButton = new Button(images.getDrawable("apiButton"));
APIButton.setPosition(405, 310);
GameButton = new Button(images.getDrawable("gameButton"));
GameButton.setPosition(515, 310);
SFXClick = Gdx.audio.newSound(Gdx.files.internal("assets/button_click.wav"));
//Add our actors to the stage
stage.addActor(SFXButton);
stage.addActor(APIButton);
stage.addActor(GameButton);
//Set up our Url request to be used when clicking the button
WeatherUrl = "http://api.openweathermap.org/data/2.5/weather?q=San%20Francisco,US";
request = new HttpRequest(HttpMethods.GET);
request.setUrl(WeatherUrl);
SanFrancisco = new City("Unavailable","Unavailable","0","0"); //init san fran to be displayed before they have clicked the button
//initialize the game screen that we will switch to when the button is pressed
gamescreen = new GameScreen();
}
@Override
public void dispose() {
spriteBatch.dispose();
stage.dispose();
}
@Override
public void render(float delta) {
stage.act(delta);
stage.draw();
//Begin sprite batch
spriteBatch.begin();
//Set our on click listeners for our buttons
if (SFXButton.isPressed())
SFXClick.play();
if(APIButton.isPressed())
{
CallApi();
}
if(GameButton.isPressed())
LoadGame();
//Set font color and render the screen
font.setColor(Color.RED);
font.draw(spriteBatch, "PennyPop", 455 - font.getBounds("PennpyPop").width/2,
460 + font.getBounds("PennyPop").height/2);
font.setColor(Color.BLACK);
font.draw(spriteBatch, "Current Weather", 900 - font.getBounds("PennpyPop").width/2,
460 + font.getBounds("PennyPop").height/2);
font.setColor(Color.LIGHT_GRAY);
font.draw(spriteBatch, SanFrancisco.Name, 940 - font.getBounds("PennpyPop").width/2,
420 + font.getBounds("PennyPop").height/2);
font.setColor(Color.RED);
font.draw(spriteBatch, SanFrancisco.CurrentCondition, 950 - font.getBounds("PennpyPop").width/2,
300 + font.getBounds("PennyPop").height/2);
font.draw(spriteBatch, SanFrancisco.Temperature + " Degrees,", 920 - font.getBounds("PennpyPop").width/2,
270 + font.getBounds("PennyPop").height/2);
font.draw(spriteBatch, SanFrancisco.WindSpeed, 1200 - font.getBounds("PennpyPop").width/2,
270 + font.getBounds("PennyPop").height/2);
//End or sprite batch
spriteBatch.end();
}
//Handles calling our API
public void CallApi(){
//Sends our stored HTTPRequest object
Gdx.net.sendHttpRequest(request, new HttpResponseListener() {
@Override
public void handleHttpResponse(HttpResponse httpResponse) {
//Uses our private response reader object to give us a the JSON from the api call
JSONObject json = HttpResponseReader(httpResponse);
//Gets the name of the city
SanFrancisco.Name = (String) json.get("name");
//Parsed through our returned JSON for the weather key
JSONArray WeatherArray = (JSONArray) json.get("weather");
//Gets the actual weather dictionary
JSONObject Weather = (JSONObject) WeatherArray.get(0);
//Finally get the value with the key of description and assign it
//To the San Fran current conditions field
SanFrancisco.CurrentCondition = (String) Weather.get("description");
//Gets the actual main dictionary
JSONObject main = (JSONObject) json.get("main");
//Finally get the values based on the keys
SanFrancisco.Temperature = (String) Double.toString((double) main.get("temp"));
//Finally get the wind speed
JSONObject wind = (JSONObject) json.get("wind");
SanFrancisco.WindSpeed = (String) Double.toString((double) wind.get("speed"));
}
@Override
public void failed(Throwable t) {
Gdx.app.log("Failed ", t.getMessage());
}
});
}
//When the button game button is clicked should load the connect four game
public void LoadGame(){
hide();
gamescreen.show();
}
//Converts our HttpResponse into a JSON OBject
private static JSONObject HttpResponseReader(HttpResponse httpResponse){
BufferedReader read = new BufferedReader(new InputStreamReader(httpResponse.getResultAsStream()));
StringBuffer result = new StringBuffer();
String line = "";
try {
while ((line = read.readLine()) != null) {
result.append(line);
}
JSONObject json;
try {
json = (JSONObject)new JSONParser().parse(result.toString());
return json;
} catch (ParseException e) {
e.printStackTrace();
}
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
@Override
public void resize(int width, int height) {
stage.setViewport(width, height, false);
}
@Override
public void hide() {
Gdx.input.setInputProcessor(null);
}
@Override
public void show() {
Gdx.input.setInputProcessor(stage);
render(0);
}
@Override
public void pause() {
// Irrelevant on desktop, ignore this
}
@Override
public void resume() {
// Irrelevant on desktop, ignore this
}
}
This is how I always implement screen switching:
First the main class needs to extend Game (From com.badlogic.gdx.Game) and you will need to have a new field of type Game:
public class ConnectFourApplication extends Game{
private Game game;
Now initialize game in the constructor:
public ConnectFourApplication(){
game = this; // Since this class extends Game
To set screen to MainScreen, now, all you need to do is to use setScreen(new MainScreen(game)); method (passing game so we can set screens from MainScreen class)
You now need a new constructor for MainScreen class, and a new field:
private Game game;
public MainScreen(Game game){
this.game = game;
Now you can use game.setScreen(new Screen(game)); to set the screen to yet another class that implements Screen.
But now, in the main class, in the render() method you must use super.render(); to make use everything from other screens render!
public void render() {
clearWhite();
super.render();
}
PS: Make sure that the class you are making as a screen, actually, implements Screen.
You have an example for this and many other concepts on LibGDX.info
来源：https://stackoverflow.com/questions/25837013/switching-between-screens-libgdx