NSResponder方法只调用setNeedsDisplay

Question

我有一个openGl视图的子类。在其中一种方法中，我设置了一个标记来绘制背景黑色或白色。在方法结束时，我调用setNeedsDisplay。永远不会被称为！我在mouseDownEvent中也有一个setNeedsDisplay。当我点击视图IT CALLS IT！我的背景改变了颜色。有任何想法吗？这是代码。

在openGL视图中

-(long)setBackgroundBlack:(BOOL)flag{
if(flag == YES){
    blkBg = YES;

    [self setNeedsDisplay:YES];

}else if (flag == NO){
    blkBg = NO;
    [self  setNeedsDisplay:YES];

}

if (flag == blkBg){

    return 0;



}else{
    return 1;
}
}

- (void)mouseDown:(NSEvent *)theEvent
{
lastDragLocation = [[self superview] convertPoint:[theEvent locationInWindow] fromView:nil];
    NSPoint newPoint;
    newPoint.x = lastDragLocation.x * (2.0 / self.bounds.size.width) - 1.0;
    newPoint.y = lastDragLocation.y * (2.0 / self.bounds.size.width) - 1.0;
    [self setNeedsDisplay:YES];
}

在app appate

中

-(IBAction)claim1931BW:(id)sender{

long res = [_myPlotView setBackgroundBlack:NO];

NSLog(@"%ld", res);
[self.cie1931BWMenu setState:NSOnState];
[self.cie1931ColorMenu setState:NSOffState];

}