Question

我尝试将数据从MainActivity传递到我的类VistaJuego，它会在屏幕上移动玩偶但当它与障碍物碰撞时，游戏停止并且有意图应该转到另一个活动。我需要MainActivity的上下文来实现我的意图，但Eclipse总是显示NullPointerException。

我的MainActivity 公共类MainActivity扩展Activity { RelativeLayout相对; static Activity ac;

@Override
protected void onCreate(Bundle savedInstanceState) {
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    vistafaba=(VistaJuego)findViewById(R.id.faba);
    relative=(RelativeLayout)findViewById(R.id.relative);
    ac=this.getActivity();
}
public void goToActivityLosed(){
    Intent i= new Intent(this,ActivityLosed.class);
    startActivity(i);
}

我的VistaJuego

 public class VistaJuego extends View {



ThreadJuego juego = new ThreadJuego();
ThreadFaba hiloFaba= new ThreadFaba();

MainActivity main;

public VistaJuego(Context context, AttributeSet attrs) {
    super(context, attrs);
    //dialogo= new DialogoFinJuego(MainActivity.this);
    main= new MainActivity();

} public void whenBeanCrash（Grafico elementofaba，Grafico elementoBotella）{

    if((elementofaba.getPosX()+elementofaba.getAncho()>=elementoBotella.getPosX()+15)&&
            (elementofaba.getPosX()+elementofaba.getAncho() <= elementoBotella.getPosX()+elementoBotella.getAncho()+15)&&
            (elementofaba.getPosY()+elementofaba.getAlto()>=elementoBotella.getPosY())
            && (elementofaba.getPosY()+elementofaba.getAlto() <= elementoBotella.getPosY()+elementoBotella.getAlto())){
        juego.detener();
        hiloFaba.detener();

        main.goToActivityLosed();

    }

Answer 1

如果要启动活动，请使用上下文而非活动

示例：

public void whenBeanCrash(Grafico elementofaba,Grafico elementoBotella){
     // ...
     // and not main.goToActivityLosed()
     Context context = getContext();
     context.startActivity(new Intent(context, YourActivity.class));
}

或者您可以创建一个设置活动对象的函数：

public void setActivity(MainActivity activity){
       this.activity = activity;
       // and now in whenBeanCrash() you can use this.activity to call function from this class
}

传递数据从活动移动到类扩展视图

1 个答案: