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Iphone 如何在UIButton子类中重写-drawrect？

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Iphone 如何在UIButton子类中重写-drawrect？,iphone,uibutton,Iphone,Uibutton,嗨。我需要在自定义按钮上写一些文字。所以我将UIButton子类化。在drawrect中，我编写所需的文本。问题是，文本最终位于按钮下方。在我写完我的文本后，UIButton的drawrect继续在我的上方绘制 我甚至没有打电话给[super drawrect:rect]，尽管我在画画之前就想打电话给它。看起来UIButton的drawrect无论如何都会被调用 有什么想法吗？谢谢。您不需要为UIButton创建子类来添加一些文本。以下是在UIViewController子类的-viewDidL

嗨。我需要在自定义按钮上写一些文字。所以我将UIButton子类化。在drawrect中，我编写所需的文本。问题是，文本最终位于按钮下方。在我写完我的文本后，UIButton的drawrect继续在我的上方绘制

我甚至没有打电话给[super drawrect:rect]，尽管我在画画之前就想打电话给它。看起来UIButton的drawrect无论如何都会被调用

有什么想法吗？谢谢。

您不需要为UIButton创建子类来添加一些文本。以下是在UIViewController子类的-viewDidLoad方法中为自定义按钮设置按钮标题的示例：

UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
button.frame = CGRectMake(0, 0, 44, 44);
[button setTitle:@"x" forState:UIControlStateNormal];
[self.view addSubview:button];
您还可以设置按钮的字体属性，或使用-setTitleColor:forState:”更改颜色。

在按钮视图上添加子视图如何？然后你就可以完全控制它，而不在乎按钮做了什么。你甚至可以把它做成一个标签，保存自己的drawRect。

正如其他人所说，你不需要对UIButton进行子类化——事实上，最好不要这样做，因为UIButton非常复杂（正如你所发现的）。您有三种选择：

  • 将按钮标题留空，并在所需位置向按钮添加新文本字段
  • 如果使用3.0，请访问按钮的标签属性。虽然标签本身是只读的，但其属性（包括框架）不是只读的
  • 子类UIControl。UIControl是UIView，因此您可以添加其他视图-文本和图像，而UIView实现了操作消息行为（
    addTarget:action:forControlEvents:
    ）。UIButton在此基础上实现状态性
如果您不需要UIButton的
setTitle:forState:
和相关功能，但是您使用了大量这些控件，那么我会使用第三个选项。否则，请使用第一个答案（如果您使用的是3.0，则使用第二个）。

根据您对其他答案之一的评论，这是一个问“我如何使用Y实现X以实现Z？”的情况，而您实际上应该问“我如何实现Z？”

如果您想让按钮在图像上方而不是旁边绘制文本，只需将图像作为按钮的背景图像即可。使用
setBackgroundImage:forState:
，而不是
setImage:forState:
，然后正常设置标题

在任何情况下，您都必须在
drawRect:
中绘制图像，或者将文本移动到子视图中，以便在图像上方绘制。我提到的解决方案是第二个选项的一个版本。

这对我来说很好…（忽略复杂的绘图代码）

  • 创建UIButton的子类
  • 在故事板中创建UIButton
  • 转到Identity Inspector并键入自定义名称 按钮类
    • 下面是我的UIButton代码：

    h文件：

    #import <UIKit/UIKit.h>

@interface DoneButton : UIButton

@property (assign, nonatomic) BOOL selected;

@end
    如果选择按钮，则绘制第一个代码，否则绘制其他代码。
    我更喜欢这种方法，因为我使用绘制代码。因此，这节省了大量时间，您无需创建数千个PNG或JPEG。

    让我添加一些细节。按钮是一个小圆形对象的图像。如果我让默认标题发生，标题将显示在按钮的右侧，而不是顶部。所以我把标题留空，我想在上面画标题。我需要的字体大小可以容纳大约三个字符。但如果我以上面的操作为例，那么“x”将显示在按钮的一侧，而不是顶部。下面是使用setTitle时的情况，奇怪的是，当我这样做时，我仍然会显示在图像下，现在是背景图像-现在没有前景图像。我相信现在发生的事情是调用了我的drawRect，然后调用了super的drawRect，对我绘制的文本进行了透支。背景图像将在drawRect:上方绘制，但您实际上不需要自定义绘制，因为标题将在背景图像上方绘制。@mahboudz:正如Brent所说，您不应该覆盖-drawRect:如果您只需要图像上的文本。使用setTitle:forState:设置文本。你的情况听起来正是UIButton的目的——为什么要重新发明轮子？ 
     #import "DoneButton.h"

    @implementation DoneButton

    @synthesize selected = _selected;

    - (id)initWithFrame:(CGRect)frame
    {
        self = [super initWithFrame:frame];
        if (self) {
            // Initialization code
        }
        return self;
    }

    - (void)setSelected:(BOOL)selected
    {
        if (_selected != selected) {
            _selected = selected;
            [self setNeedsDisplay];
        }
    }


    - (void)drawRect:(CGRect)rect
    {
        // Drawing code

        if (_selected) {
            //// Color Declarations
            UIColor* color2 = [UIColor colorWithRed: 0 green: 0 blue: 0 alpha: 1];

            //// Bezier Drawing
            UIBezierPath* bezierPath = [UIBezierPath bezierPath];
            [bezierPath moveToPoint: CGPointMake(49.39, 31.25)];
            [bezierPath addLineToPoint: CGPointMake(49.39, 31.25)];
            [bezierPath addCurveToPoint: CGPointMake(46.64, 25.19) controlPoint1: CGPointMake(49.39, 29.02) controlPoint2: CGPointMake(48.38, 26.94)];
            [bezierPath addCurveToPoint: CGPointMake(44.3, 18.95) controlPoint1: CGPointMake(46.63, 22.72) controlPoint2: CGPointMake(45.88, 20.53)];
            [bezierPath addCurveToPoint: CGPointMake(42.44, 17.59) controlPoint1: CGPointMake(43.75, 18.4) controlPoint2: CGPointMake(43.13, 17.95)];
            [bezierPath addCurveToPoint: CGPointMake(38.07, 16.61) controlPoint1: CGPointMake(41.17, 16.93) controlPoint2: CGPointMake(39.67, 16.62)];
            [bezierPath addCurveToPoint: CGPointMake(33.15, 13.95) controlPoint1: CGPointMake(36.62, 15.18) controlPoint2: CGPointMake(34.95, 14.23)];
            [bezierPath addCurveToPoint: CGPointMake(32.78, 13.92) controlPoint1: CGPointMake(33.03, 13.93) controlPoint2: CGPointMake(32.9, 13.93)];
            [bezierPath addCurveToPoint: CGPointMake(32, 13.86) controlPoint1: CGPointMake(32.52, 13.89) controlPoint2: CGPointMake(32.26, 13.86)];
            [bezierPath addLineToPoint: CGPointMake(32, 13.86)];
            [bezierPath addLineToPoint: CGPointMake(32, 13.86)];
            [bezierPath addLineToPoint: CGPointMake(32, 13.86)];
            [bezierPath addLineToPoint: CGPointMake(32, 13.86)];
            [bezierPath addCurveToPoint: CGPointMake(31.38, 13.91) controlPoint1: CGPointMake(31.79, 13.86) controlPoint2: CGPointMake(31.59, 13.89)];
            [bezierPath addCurveToPoint: CGPointMake(30.85, 13.95) controlPoint1: CGPointMake(31.2, 13.92) controlPoint2: CGPointMake(31.02, 13.92)];
            [bezierPath addCurveToPoint: CGPointMake(26.92, 15.74) controlPoint1: CGPointMake(29.44, 14.17) controlPoint2: CGPointMake(28.12, 14.8)];
            [bezierPath addCurveToPoint: CGPointMake(25.94, 16.61) controlPoint1: CGPointMake(26.58, 16.01) controlPoint2: CGPointMake(26.25, 16.29)];
            [bezierPath addCurveToPoint: CGPointMake(24.13, 16.76) controlPoint1: CGPointMake(25.31, 16.61) controlPoint2: CGPointMake(24.71, 16.66)];
            [bezierPath addCurveToPoint: CGPointMake(19.7, 18.95) controlPoint1: CGPointMake(22.41, 17.06) controlPoint2: CGPointMake(20.88, 17.77)];
            [bezierPath addCurveToPoint: CGPointMake(17.36, 25.19) controlPoint1: CGPointMake(18.12, 20.53) controlPoint2: CGPointMake(17.37, 22.72)];
            [bezierPath addCurveToPoint: CGPointMake(14.61, 31.25) controlPoint1: CGPointMake(15.62, 26.94) controlPoint2: CGPointMake(14.61, 29.02)];
            [bezierPath addLineToPoint: CGPointMake(14.61, 31.25)];
            [bezierPath addCurveToPoint: CGPointMake(14.61, 31.25) controlPoint1: CGPointMake(14.61, 31.25) controlPoint2: CGPointMake(14.61, 31.25)];
            [bezierPath addCurveToPoint: CGPointMake(14.66, 31.92) controlPoint1: CGPointMake(14.61, 31.48) controlPoint2: CGPointMake(14.64, 31.7)];
            [bezierPath addCurveToPoint: CGPointMake(14.7, 32.4) controlPoint1: CGPointMake(14.67, 32.08) controlPoint2: CGPointMake(14.67, 32.24)];
            [bezierPath addCurveToPoint: CGPointMake(15.86, 35.44) controlPoint1: CGPointMake(14.86, 33.46) controlPoint2: CGPointMake(15.27, 34.48)];
            [bezierPath addCurveToPoint: CGPointMake(15.97, 35.64) controlPoint1: CGPointMake(15.9, 35.5) controlPoint2: CGPointMake(15.93, 35.57)];
            [bezierPath addCurveToPoint: CGPointMake(17.36, 37.32) controlPoint1: CGPointMake(16.36, 36.23) controlPoint2: CGPointMake(16.83, 36.78)];
            [bezierPath addCurveToPoint: CGPointMake(17.49, 38.98) controlPoint1: CGPointMake(17.36, 37.89) controlPoint2: CGPointMake(17.41, 38.44)];
            [bezierPath addCurveToPoint: CGPointMake(18.35, 41.7) controlPoint1: CGPointMake(17.65, 39.95) controlPoint2: CGPointMake(17.92, 40.87)];
            [bezierPath addCurveToPoint: CGPointMake(19.7, 43.55) controlPoint1: CGPointMake(18.7, 42.38) controlPoint2: CGPointMake(19.15, 43)];
            [bezierPath addCurveToPoint: CGPointMake(25.93, 45.89) controlPoint1: CGPointMake(21.28, 45.13) controlPoint2: CGPointMake(23.47, 45.88)];
            [bezierPath addCurveToPoint: CGPointMake(27.61, 47.28) controlPoint1: CGPointMake(26.47, 46.42) controlPoint2: CGPointMake(27.02, 46.89)];
            [bezierPath addCurveToPoint: CGPointMake(32, 48.64) controlPoint1: CGPointMake(28.96, 48.16) controlPoint2: CGPointMake(30.44, 48.64)];
            [bezierPath addLineToPoint: CGPointMake(32, 48.64)];
            [bezierPath addLineToPoint: CGPointMake(32, 48.64)];
            [bezierPath addLineToPoint: CGPointMake(32, 48.64)];
            [bezierPath addLineToPoint: CGPointMake(32, 48.64)];
            [bezierPath addCurveToPoint: CGPointMake(38.06, 45.89) controlPoint1: CGPointMake(34.23, 48.64) controlPoint2: CGPointMake(36.31, 47.63)];
            [bezierPath addCurveToPoint: CGPointMake(44.3, 43.55) controlPoint1: CGPointMake(40.53, 45.88) controlPoint2: CGPointMake(42.72, 45.13)];
            [bezierPath addLineToPoint: CGPointMake(44.3, 43.55)];
            [bezierPath addLineToPoint: CGPointMake(44.3, 43.55)];
            [bezierPath addCurveToPoint: CGPointMake(46.64, 37.31) controlPoint1: CGPointMake(45.88, 41.97) controlPoint2: CGPointMake(46.63, 39.78)];
            [bezierPath addCurveToPoint: CGPointMake(49.39, 31.25) controlPoint1: CGPointMake(48.38, 35.56) controlPoint2: CGPointMake(49.39, 33.48)];
            [bezierPath addLineToPoint: CGPointMake(49.39, 31.25)];
            [bezierPath closePath];
            [color2 setStroke];
            bezierPath.lineWidth = 1;
            [bezierPath stroke];


            //// Bezier 2 Drawing
            UIBezierPath* bezier2Path = [UIBezierPath bezierPath];
            [bezier2Path moveToPoint: CGPointMake(22.42, 29.85)];
            [bezier2Path addLineToPoint: CGPointMake(29.74, 37.17)];
            [bezier2Path addLineToPoint: CGPointMake(41.58, 25.33)];
            bezier2Path.usesEvenOddFillRule = YES;

            [color2 setStroke];
            bezier2Path.lineWidth = 1;
            [bezier2Path stroke];

        } else {

            //// Color Declarations
            UIColor* color3 = [UIColor colorWithRed: 0.5 green: 0.5 blue: 0.5 alpha: 1];

            //// Bezier 2 Drawing
            UIBezierPath* bezier2Path = [UIBezierPath bezierPath];
            [bezier2Path moveToPoint: CGPointMake(22.42, 29.85)];
            [bezier2Path addLineToPoint: CGPointMake(29.74, 37.17)];
            [bezier2Path addLineToPoint: CGPointMake(41.58, 25.33)];
            bezier2Path.usesEvenOddFillRule = YES;

            [color3 setStroke];
            bezier2Path.lineWidth = 1;
            [bezier2Path stroke];
        }
    }