Question

我有自定义画布的主要活动：

    public void onCreate(Bundle savedInstanceState) {
        ...
        CustomCanvas c = new CustomCanvas(this);
        c.requestFocus();
        cll = (LinearLayout)findViewById(R.id.CLL);
        cll.addView(c);
    }

    public void qwerty(String w) {
        ....
        TextView abc = (TextView)findViewById(R.id.TextViewabc);
        abc.setText(w);
        ....
    }

在CustomCanvas中，我有一个带有SimpleOnGestureListener的GestureDetector。我想从SimpleOnGestureListener的方法调用qwerty（）（例如onSingleTapConfirmed）

这可能吗？如果没有，还有另一种方法吗？感谢

....编辑.....（更多信息）

GestureDetector是我的CustomCanvas

中的一个对象

public class CustomCanvas extends View {

    GestureDetector gd;
    ...

    public CustomCanvas(final Context context) {
        super(context);

        gd = new GestureDetector(getContext(), new SimpleOnGestureListener() {
            ....
            //  I also use getScrollX() and getScrollY() in some of the methods here
        });
    }

    ....

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        return gd.onTouchEvent(ev);
    }
}

Answer 1

你有两个选择。要么在Activity中实现SimpleOnGestureListener并将其设置为CustomCanvas，要么将Activity传递给CustomCanavas，以便可以从CustomCanvas类中的侦听器调用qwerty（）。

更新

public class CustomCanvas extends View {

    GestureDetector gd;
    YourActivity mYourActivity;
    ...

    public CustomCanvas(final Context context) {
        super(context);

        gd = new GestureDetector(getContext(), new SimpleOnGestureListener() {                   
              public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY){
                  // this implementation makes no sense 
                  if(mYourActivity != null){
                     mYourActivity.qwerty(); 
                  }    
              }    
        });
    }

    public setActivity(YourActivity activity){
         mYourActivity = activity;
    }
}

在Activity类中，您必须将活动传递给CustomCanvas。

public class YourActivity {

    public void onCreate(Bundle savedInstanceState) {
        ...
        CustomCanvas c = new CustomCanvas(this);

        // pass the activity to the canvas
        c.setActivity(this);

        c.requestFocus();
        cll = (LinearLayout)findViewById(R.id.CLL);
        cll.addView(c);
    }

    public void qwerty(String w) {
        ....
        TextView abc = (TextView)findViewById(R.id.TextViewabc);
        abc.setText(w);
        ....
    }
}

从SimpleOnGestureListener调用活动中的函数

1 个答案: