How to access other elements in click listeners in libgdx

android, java, libgdx, tablelayout

Solution

William Morrison listed a number of ways you can create ClickListeners. I prefer the method of anonymous classes myself and I see that is the method used in your question.

You need to make all references outside of your anonymous class final so that you can reference them inside. This is how java ensures the reference does not change. Look at my code (and comments) for a complete solution, I only had to change a couple things. (I also have my skin file located at 'skin/uiskin.json' so keep that in mind if you wish to use this code).

import com.badlogic.gdx.ApplicationListener;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.scenes.scene2d.InputEvent;
import com.badlogic.gdx.scenes.scene2d.Stage;
import com.badlogic.gdx.scenes.scene2d.ui.Label;
import com.badlogic.gdx.scenes.scene2d.ui.Skin;
import com.badlogic.gdx.scenes.scene2d.ui.Table;
import com.badlogic.gdx.scenes.scene2d.ui.TextButton;
import com.badlogic.gdx.scenes.scene2d.utils.ClickListener;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class ClickTest implements ApplicationListener {
    private Stage stage;
    private Skin skin;

    @Override public void create() {
        Gdx.app.log("CREATE", "App Opening");

        this.skin = new Skin(Gdx.files.internal("skin/uiskin.json"));
        stage = new Stage();
        Gdx.input.setInputProcessor(stage);
        Table table = new Table();
        table.setFillParent(true);
        stage.addActor(table);

        String sentence = "One two three four five six seven eight";
        String[] temp = sentence.split(" ");
        List<String> words = new ArrayList<String>(Arrays.asList(temp));

        final Label info = new Label("Welcome to Android!", skin);

        for (int i = 0; i < words.size(); i++) {
            // make i final here so you can reference it inside
            // the anonymous class
            final int index = i; 

            TextButton button = new TextButton(words.get(i), skin);
            table.add(button);

            button.addListener(new ClickListener() {
                @Override public void clicked(InputEvent event, float x, float y) {
                    // When you click the button it will print this value you assign.
                    // That way you will know 'which' button was clicked and can perform
                    // the correct action based on it.
                    Gdx.app.log("button", "clicked " + index);  

                    info.setText(Integer.toString(index));
                };
            });
        }

        table.row();
        // Changed this so it actually centers the label.
        table.add(info).colspan(words.size()).expandX(); 

        Gdx.input.setInputProcessor(stage);

        Gdx.gl20.glClearColor(0f, 0f, 0f, 1);
    }

    @Override public void render() {
        this.stage.act();
        Gdx.gl20.glClear(GL20.GL_COLOR_BUFFER_BIT);
        Gdx.gl20.glEnable(GL20.GL_BLEND);
        this.stage.draw();
    }

    @Override public void dispose() {
        Gdx.app.log("DISPOSE", "App Closing");
    }

    @Override public void resize(final int width, final int height) {
        Gdx.app.log("RESIZE", width + "x" + height);
        Gdx.gl20.glViewport(0, 0, width, height);
        this.stage.setViewport(width, height, false);
    }

    @Override public void pause() { }

    @Override public void resume() { }
}

Problem

Original source

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