ios - 如何设置 CATextLayer 文本垂直位置？

Question

我使用以下代码在我的应用中创建了 UILabel 和 CATextLayer

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.textLabel = [[UILabel alloc] initWithFrame:CGRectMake(20, 90, 20, 20)];
    self.textLabel.text = @"1";
    self.textLabel.font = [UIFont systemFontOfSize:12];
    self.textLabel.backgroundColor = [UIColor redColor];
    [self.view addSubview:self.textLabel];

    self.textLayer = [CATextLayer layer];
    [self.textLayer setString:@"1"];
    [self.textLayer setFont:(__bridge CFTypeRef)([UIFont systemFontOfSize:12])];
    self.textLayer.backgroundColor = [UIColor greenColor].CGColor;
    self.textLayer.frame = CGRectMake(70, 90, 50, 20);
    [self.view.layer addSublayer:self.textLayer];
}

结果是

红色的是UILabel，绿色的是CALayer。我想知道如何垂直对齐 CALayer 中的文本，如 UILabel` 所示。

Answer 1

实际上，这对我有用:

self.layer.addSublayer(textLayer)
textLayer.font = font
textLayer.fontSize = font.pointSize
textLayer.frame = CGRectMake(self.layer.bounds.origin.x, ((self.layer.bounds.height - textLayer.fontSize) / 2) - lineWidth, self.layer.bounds.width, self.layer.bounds.height)
textLayer.alignmentMode - kCAAlignmentCenter
textLayer.contentsScale = UIScreen.mainScreen().scale

LineWidth 是我用来“框定”我的边界区域的。这使我的文本在垂直和水平方向上居中。