如何绘制NSString atPoint withAttributes和调整大小？

Question

我可以绘制我的NSString，但是在绘制它们时我无法调整大小。 我的drawRect：方法是：

- (void)drawRect:(CGRect)rect
{

NSArray *objectArray = [NSArray arrayWithObjects:[UIFont systemFontOfSize:80.0f], nil];
NSArray *keyArray = [NSArray arrayWithObjects:@"NSFontAttributeName", nil];
NSMutableDictionary *textAttributes = [NSMutableDictionary dictionaryWithObjects:objectArray forKeys:keyArray];
NSString *myTestString = @"Test String";
[textAttributes setObject:[UIColor redColor] forKey:NSForegroundColorAttributeName];
[myTestString drawAtPoint:CGPointMake(20, 30) withAttributes:textAttributes];
[myTestString drawInRect:CGRectMake(50, 50, 500, 500) withAttributes:textAttributes];

NSLog(@"wrote %@ with %@", myTestString, textAttributes);
}

textAttributes看起来不错，并且字体信息返回为：

 NSFontAttributeName = "<UICTFont: 0x14eeff40> font-family: \".HelveticaNeueInterface-M3\"; font-weight: normal; font-style: normal; font-size: 80.00pt"

我可以使用属性数组正确更改颜色，为什么这会导致文本成为默认的10pt大小？

Answer 1

NSAttributedString是您想要的。 UICatalog示例代码提供了NSAttributedString用法的示例：

#pragma mark - UIPickerViewDataSource

- (NSAttributedString *)pickerView:(UIPickerView *)pickerView attributedTitleForRow:(NSInteger)row forComponent:(NSInteger)component
{
    NSMutableAttributedString *attrTitle = nil;

    // note: for the custom picker we use custom views instead of titles
    if (pickerView == self.myPickerView)
    {
        if (row == 0)
        {
            NSString *title;
            if (component == 0)
                title = [self.pickerViewArray objectAtIndex:row];
            else
                title = [[NSNumber numberWithInt:row] stringValue];

            // apply red text for normal state
            attrTitle = [[NSMutableAttributedString alloc] initWithString:title];
            [attrTitle addAttribute:NSForegroundColorAttributeName
                          value:[UIColor redColor]
                          range:NSMakeRange(0, [attrTitle length])];
        }
    }

    return attrTitle;
}

iOS上的Stanford U MOOC课程（由Paul Hegarty运行， 可以在iTunes上找到 ）在第4讲中概述了NSAttributedString的用法。第5讲还提供了NSAttributedString代码演示，您可以遵循。 最后，github用户m2mtech已发布了该课程的所有代码练习和作业的存储库 ，您可以在此处下载相关的项目文件。