从主要活动切换到游戏面板类（Android Studio）后游戏崩溃

Question

我制作了2D游戏，效果很好。我决定创建一个简单的＆＃34;开始屏幕＆＃34;应该显示高分和＆＃34;开始＆＃34;应该开始游戏的按钮。

我认为我可以只使用常规意图从一个活动转到另一个活动，但它不起作用。单击＆＃34;开始＆＃34;然后应用程序崩溃按钮。

我使用场景管理器，因此并非所有代码都是在游戏面板中编写的。

这是我的MainActivity

package com.example.korisnik_pc.a2dgame;

import android.app.Activity;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Button;

    public class MainActivity extends Activity {

        @Override
        protected void onCreate(Bundle savedInstanceState) {

            Button button;
            super.onCreate(savedInstanceState);
            getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN); // MAKE IT FULLSCREEN
            this.requestWindowFeature(Window.FEATURE_NO_TITLE); // REMOVES TOOLBAR

            // setting the screen dimensions
            DisplayMetrics dm = new DisplayMetrics();
            getWindowManager().getDefaultDisplay().getMetrics(dm);
            Constants.SCREEN_HEIGHT = dm.heightPixels;
            Constants.SCREEN_WIDTH = dm.widthPixels;
            setContentView(R.layout.activity_main);

            button = (Button) findViewById(R.id.button);

            button.setOnClickListener(new View.OnClickListener() {
                public void onClick(View v) {
                    Intent intent = new Intent(MainActivity.this, GamePanel.class);
                    startActivity(intent);
                }
            });


        }

游戏小组

public class GamePanel extends SurfaceView implements SurfaceHolder.Callback {
    private MainThread thread;
    private SceneManager sceneManager;


    public GamePanel(Context context) {
        super(context);

        getHolder().addCallback(this);

        thread = new MainThread(getHolder(), this);

        sceneManager = new SceneManager();


        setFocusable(true);
    }


    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        thread = new MainThread(getHolder(), this);

        thread.setRunning(true);
        thread.start();
    }


    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        boolean retry = true;
        while (true) {
            try {
                thread.setRunning(false);
                thread.join();
            } catch (Exception e) {
                e.printStackTrace();
            }
            retry = false;
        }
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        sceneManager.receiveTouch(event);


        return true;


    }

    public void update() {

        sceneManager.update();

    }


    public void draw(Canvas canvas) {
        super.draw(canvas);
        sceneManager.draw(canvas);

    }


}