在子类的初始化方法中，UIView我添加了几个UIImageViews. 渲染视图时，它们存在于subviews数组中并具有有效的框架矩形，但不会在屏幕上绘制。有谁知道为什么会这样？
- (id) initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (!self)
return nil;
[self commonInit];
return self;
}
- (void) commonInit {
_padding = 128.0f;
// Add the chord views here
_chordImages = [NSArray arrayWithObjects:[UIImage imageNamed:@"fn_maj_x_x_x_x_1_e_1_fn"], [UIImage imageNamed:@"en_maj_x_x_x_x_1_e_1_en"], [UIImage imageNamed:@"dn_maj_x_x_x_x_1_d_1_f#"], [UIImage imageNamed:@"an_min_x_x_x_x_1_a_1_en"], nil];
CGFloat containerWidth = [self bounds].size.width;
NSLog(@"containerWidth: %f",containerWidth);
CGFloat chordWidth = [[_chordImages objectAtIndex:0] size].width;
NSLog(@"chordWidth: %f",chordWidth);
CGFloat chordMarkerWidth = [[[GVChordMarkerView alloc] initWithFrame:CGRectMake(0, 0, 12, 12)] frame].size.width;
NSLog(@"chordMarkerWidth: %f",chordMarkerWidth);
// [self setFrame:CGRectMake(chordXPosition, 0, [self bounds].size.width, [self bounds].size.height]);
CGFloat chordXPosition = 0;
CGFloat chordXSpacing = (containerWidth/4 - (chordMarkerWidth + chordWidth));
chordXPosition += containerWidth/4;
for (NSUInteger i = 0; i < [_chordImages count]; i++) {
chordXPosition += chordXSpacing;
CGRect chordImageViewFrame = CGRectMake(chordXPosition, 0, [[_chordImages objectAtIndex:0] size].width, [[_chordImages objectAtIndex:0] size].height);
UIImageView *chordImageView = [[UIImageView alloc] initWithFrame:chordImageViewFrame];
[self addSubview:chordImageView];
chordXPosition += (chordMarkerWidth + chordWidth);
}
NSLog(@"Finished");
}