在按钮点击上显示interstital广告

Question

所以在我的LIBGDX游戏中，我想在点击按钮时显示Interstital广告，例如，重启游戏的按钮。

在我有这个按钮的课程中，我已经全局设置了这个：

 AdControlller adController;


    public MainMenu(AdControlller adController) {
        this.adController = adController;
    }

然后在按钮的touchUp方法中我设置了这个：

public void touchUp (InputEvent event, float x, float y, int pointer, int button){
                howToPlayButton.addAction(Actions.scaleTo(1, 1,.1f));
                mainMenu.addAction(Actions.sequence(Actions.fadeOut(0.24f),Actions.run(new Runnable() {
                    @Override
                    public void run() {
                        if (adController.isNetworkConnected()) {
                            adController.showInterstitalAd(new Runnable() {
                                @Override
                                public void run() {
                                    game.setScreen(new HowToPlay(game));
                                    loopMusic.dispose();
                                }
                            });
                        }

                    }
                })));

            }
        });

问题是，当我点击按钮时，它会给我带来这个logcat错误：

FATAL EXCEPTION: GLThread 148306
                                                                Process: com.mygdx.game, PID: 30808
                                                                java.lang.NullPointerException: Attempt to invoke interface method 'boolean com.mygdx.game.AdControlller.isNetworkConnected()' on a null object reference
                                                                    at com.mygdx.game.screens.MainMenu$5$1.run(MainMenu.java:167)
                                                                    at com.badlogic.gdx.scenes.scene2d.actions.RunnableAction.run(RunnableAction.java:42)
                                                                    at com.badlogic.gdx.scenes.scene2d.actions.RunnableAction.act(RunnableAction.java:32)
                                                                    at com.badlogic.gdx.scenes.scene2d.actions.SequenceAction.act(SequenceAction.java:65)
                                                                    at com.badlogic.gdx.scenes.scene2d.Actor.act(Actor.java:95)
                                                                    at com.badlogic.gdx.scenes.scene2d.Group.act(Group.java:46)
                                                                    at com.badlogic.gdx.scenes.scene2d.Stage.act(Stage.java:222)
                                                                    at com.badlogic.gdx.scenes.scene2d.Stage.act(Stage.java:186)
                                                                    at com.mygdx.game.screens.MainMenu.render(MainMenu.java:267)
                                                                    at com.badlogic.gdx.Game.render(Game.java:46)
                                                                    at com.mygdx.game.Main.render(Main.java:37)
                                                                    at com.badlogic.gdx.backends.android.AndroidGraphics.onDrawFrame(AndroidGraphics.java:474)
                                                                    at android.opengl.GLSurfaceView$GLThread.guardedRun(GLSurfaceView.java:1522)
                                                                    at android.opengl.GLSurfaceView$GLThread.run(GLSurfaceView.java:1239)

我做错了什么？

IS网络连接方法

@Override
    public boolean isNetworkConnected() {
        ConnectivityManager connMgr = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
        return (networkInfo != null && networkInfo.isConnected());
    }