Java Invalidate（）未在draw（）上调用

作废未要求提款

我在invalidate中使用了类对象和imageview

当使用类名调用invalidate时会出错

这些是我的课

请帮忙

 public class DrawingClass extends View {
       Bitmap bitmap;
       Canvas canvas;
       Paint paint;
public DrawingClass(Context context,ImageView img) {
    super(context);
    bitmap = Bitmap.createBitmap(480, 800,
            Bitmap.Config.ARGB_8888);
    canvas = new Canvas(bitmap);
    canvas.drawColor(Color.CYAN);
    paint = new Paint();
    paint.setColor(Color.RED);
    img.setImageBitmap(bitmap);
    // TODO Auto-generated constructor stub
}
@Override
protected void onDraw(Canvas canvas) {
    // TODO Auto-generated method stub
     super.onDraw(canvas);
    System.out.println("++++++++++inside on drwaw()");
     Paint paint = new Paint();
    paint.setColor(Color.GREEN);
     paint.setStrokeWidth(6);
    canvas.drawLine(50, 50, 300, 400, paint);
       }
     }

及

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}

invalidate将刷新视图。这不是一个静态方法，所以在调用methodpost时不能使用classname。请在这里发布您的异常日志…检查此项并研究示例中的fingerpaint演示它似乎很有用，让我尝试一下，谢谢you@Raghunandan

    public class AddOnClick extends Activity implements OnTouchListener{
ImageView imageView;
DrawingClass draw_cls;
@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.addstore_2);
    imageView=(ImageView)findViewById(R.id.imageView1);
    draw_cls=new DrawingClass(this,imageView);
    imageView.setOnTouchListener(this); 
}
@Override
public boolean onTouch(View v, MotionEvent event) {
    // TODO Auto-generated method stub
    int action = event.getAction();
    switch (action) {
    case MotionEvent.ACTION_DOWN:   
        draw_cls.invalidate();
                 // imageView.invalidate();
    }
    return true;
}