ボタンの背景色をプログラムで変える方法 Changing the background color of UIButton without a image file

gistfile1.m

/** 使い方 sample usage */

#define BUTTON_RADIUS         10.0f
#define BUTTON_BORDER_WIDTH   1.0f
NSString *title           = @"something";
UIButton *button          = [UIButton buttonWithType:UIButtonTypeCustom];
button.frame              = rect;
[button setTitle:title forState:UIControlStateNormal];
[button setTitleColor:[UIColor redColor] forState:UIControlStateNormal];
[button setBackgroundColor:[UIColor colorWithWhite:0.8 alpha:0.5] forState:UIControlStateNormal radius:BUTTON_RADIUS];
button.layer.borderColor  = [UIColor whiteColor].CGColor;
button.layer.borderWidth  = BUTTON_BORDER_WIDTH;
button.layer.cornerRadius = BUTTON_RADIUS;

/** 以下、必要クラス Required Classes are as follows: */

//
// UIButton+MyCategory.h
//

#import <Foundation/Foundation.h>
@interface UIButton (MyCategory)
- (void)setBackgroundColor:(UIColor *)color forState:(UIControlState)state radius:(CGFloat)radius;
- (void)setBackgroundColorString:(NSString *)colorStr forState:(UIControlState)state radius:(CGFloat)radius;
@end

//
// UIButton+MyCategory.m
//

#import "UIButton+MyCategory.h"
#import <QuartzCore/QuartzCore.h>
#import "UIColor+MyCategory.h"

@implementation UIButton (MyCategory)

/**
 * 特定のStateのボタンの背景色を変える
 * change UIButton background color for the specified button state
 * e.g. [buttonObj setBackgroundColorString:[UIColor redColor] forState:UIControlStateNormal radius:10.0f];
 *
 * @param color 新しい背景色
 * @param state 適用State
 * @param radius 角丸
 */
- (void)setBackgroundColor:(UIColor *)color forState:(UIControlState)state radius:(CGFloat)radius {
  // imageを生成して、setBackgroundImageにセットしている
  // create images dynamically, then setBackgroundImage
  UIView *view            = [[UIView alloc] initWithFrame:self.bounds];
  view.layer.cornerRadius = radius;
  view.clipsToBounds      = YES;
  view.backgroundColor    = color;
  UIGraphicsBeginImageContext(self.frame.size);
  [view.layer renderInContext:UIGraphicsGetCurrentContext()];
  UIImage *image          = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();
  [self setBackgroundImage:image forState:state];
  [view release];
}

/**
 * 特定のStateのボタンの背景色をRGB文字列で指定する
 * change UIButton background color for the specified button state
 * e.g. [buttonObj setBackgroundColorString:@"#123456" forState:UIControlStateNormal radius:10.0f];
 *
 * @param colorStr 新しい背景色
 * @param state 適用State
 * @param radius 角丸
 */
- (void)setBackgroundColorString:(NSString *)colorStr forState:(UIControlState)state radius:(CGFloat)radius {
  UIColor *color = [UIColor colorWithHexString:colorStr];
  [self setBackgroundColor:color forState:state radius:radius];
}
@end

//
// UIColor+MyCategory.h
//

#import <Foundation/Foundation.h>

/** 色をRGB指定 */
@interface UIColor (MyCategory)
+ (UIColor *)colorWithHex:(uint)rgbValue;
+ (UIColor *)colorWithHexString:(NSString *)str;
@end

//
// UIColor+MyCategory.m
//

#import "UIColor+MyCategory.h"
@implementation UIColor (MyCategory)

/**
 * RGB値からUIColorを生成する
 * Create UIColor instance from a RGB value
 * e.g. [UIColor colorWithHex:0x123456]
 *
 * @param rgbValue RGB値
 * @return RGB値から生成した[UIColor]オブジェクト
 */
+ (UIColor *)colorWithHex:(uint)rgbValue {
	return [UIColor colorWithRed:((float)((rgbValue & 0xFF0000) >> 16))/255.0 
                               green:((float)((rgbValue & 0xFF00) >> 8))/255.0 
                                blue:((float)(rgbValue & 0xFF))/255.0 alpha:1.0];
}

/**
 * RGB文字列からUIColorを生成する
 * Create UIColor instance from a RGB string
 * e.g. [UIColor colorWithHexString:@"#123456"]
 *
 * @param str RGB文字列
 * @return RGB文字列から生成した[UIColor]オブジェクト
 */
+ (UIColor *)colorWithHexString:(NSString *)str {
  const char *cStr = [str cStringUsingEncoding:NSASCIIStringEncoding];
  long x = strtol(cStr+1, NULL, 16);
  return [UIColor colorWithHex:x];
}
@end

References in English
http://stackoverflow.com/questions/2808888/is-it-even-possible-to-change-a-uibuttons-background-color
http://pastie.org/830884

References in Japanese
http://d.hatena.ne.jp/masatoshisw20/20111018/1318972544
http://d.hatena.ne.jp/masatoshisw20/20090514/1242272735