修改UISearchBar背景

转载：http://blog.csdn.net/favormm/archive/2010/11/30/6045463.aspx

UISearchBar是由两个subView组成的，一个是UISearchBarBackGround,另一个是UITextField. 而IB中没有直接操作背景的属性，在此我总结了几个方法去修改它。

1. 只显示UITextField.采用了layer mask.代码如下：

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1. //first make sure you include core animation so that the compiler will know about your view's layer
2. #import <QuartzCore/QuartzCore.h>
3. //now make a mask.  this is basically just a solid colored shape.  When you apply the mask, anywhere where the color is solid will become transparent in your view.  i used the excellent Opacity (http://likethought.com/opacity/) to generate this code, but you can do it any way you'd like
4. @interface SearchMaskLayer : CALayer {
5. }
6. @end
7. @implementation SearchMaskLayer
8. - (void)drawInContext:(CGContextRef)context
9. {
10. CGRect imageBounds = CGRectMake(0, 0, 310, 34);
11. CGRect bounds = imageBounds;
12. CGFloat alignStroke;
13. CGFloat resolution;
14. CGMutablePathRef path;
15. CGPoint point;
16. CGPoint controlPoint1;
17. CGPoint controlPoint2;
18. UIColor *color;
19. resolution = 0.5 * (bounds.size.width / imageBounds.size.width + bounds.size.height / imageBounds.size.height);
20. CGContextSaveGState(context);
21. CGContextTranslateCTM(context, bounds.origin.x, bounds.origin.y);
22. CGContextScaleCTM(context, (bounds.size.width / imageBounds.size.width), (bounds.size.height / imageBounds.size.height));
23. // Layer 1
24. alignStroke = 0.0;
25. path = CGPathCreateMutable();
26. point = CGPointMake(295.0, 32.0);
27. point.x = (round(resolution * point.x + alignStroke) - alignStroke) / resolution;
28. point.y = (round(resolution * point.y + alignStroke) - alignStroke) / resolution;
29. CGPathMoveToPoint(path, NULL, point.x, point.y);
30. point = CGPointMake(310.0, 17.0);
31. point.x = (round(resolution * point.x + alignStroke) - alignStroke) / resolution;
32. point.y = (round(resolution * point.y + alignStroke) - alignStroke) / resolution;
33. controlPoint1 = CGPointMake(303.229, 32.0);
34. controlPoint1.x = (round(resolution * controlPoint1.x + alignStroke) - alignStroke) / resolution;
35. controlPoint1.y = (round(resolution * controlPoint1.y + alignStroke) - alignStroke) / resolution;
36. controlPoint2 = CGPointMake(310.0, 25.229);
37. controlPoint2.x = (round(resolution * controlPoint2.x + alignStroke) - alignStroke) / resolution;
38. controlPoint2.y = (round(resolution * controlPoint2.y + alignStroke) - alignStroke) / resolution;
39. CGPathAddCurveToPoint(path, NULL, controlPoint1.x, controlPoint1.y, controlPoint2.x, controlPoint2.y, point.x, point.y);
40. point = CGPointMake(310.0, 17.0);
41. point.x = (round(resolution * point.x + alignStroke) - alignStroke) / resolution;
42. point.y = (round(resolution * point.y + alignStroke) - alignStroke) / resolution;
43. CGPathAddLineToPoint(path, NULL, point.x, point.y);
44. point = CGPointMake(295.0, 2.0);
45. point.x = (round(resolution * point.x + alignStroke) - alignStroke) / resolution;
46. point.y = (round(resolution * point.y + alignStroke) - alignStroke) / resolution;
47. controlPoint1 = CGPointMake(310.0, 8.771);
48. controlPoint1.x = (round(resolution * controlPoint1.x + alignStroke) - alignStroke) / resolution;
49. controlPoint1.y = (round(resolution * controlPoint1.y + alignStroke) - alignStroke) / resolution;
50. controlPoint2 = CGPointMake(303.229, 2.0);
51. controlPoint2.x = (round(resolution * controlPoint2.x + alignStroke) - alignStroke) / resolution;
52. controlPoint2.y = (round(resolution * controlPoint2.y + alignStroke) - alignStroke) / resolution;
53. CGPathAddCurveToPoint(path, NULL, controlPoint1.x, controlPoint1.y, controlPoint2.x, controlPoint2.y, point.x, point.y);
54. point = CGPointMake(15.0, 2.0);
55. point.x = (round(resolution * point.x + alignStroke) - alignStroke) / resolution;
56. point.y = (round(resolution * point.y + alignStroke) - alignStroke) / resolution;
57. CGPathAddLineToPoint(path, NULL, point.x, point.y);
58. point = CGPointMake(0.0, 17.0);
59. point.x = (round(resolution * point.x + alignStroke) - alignStroke) / resolution;
60. point.y = (round(resolution * point.y + alignStroke) - alignStroke) / resolution;
61. controlPoint1 = CGPointMake(6.771, 2.0);
62. controlPoint1.x = (round(resolution * controlPoint1.x + alignStroke) - alignStroke) / resolution;
63. controlPoint1.y = (round(resolution * controlPoint1.y + alignStroke) - alignStroke) / resolution;
64. controlPoint2 = CGPointMake(0.0, 8.771);
65. controlPoint2.x = (round(resolution * controlPoint2.x + alignStroke) - alignStroke) / resolution;
66. controlPoint2.y = (round(resolution * controlPoint2.y + alignStroke) - alignStroke) / resolution;
67. CGPathAddCurveToPoint(path, NULL, controlPoint1.x, controlPoint1.y, controlPoint2.x, controlPoint2.y, point.x, point.y);
68. point = CGPointMake(0.0, 17.0);
69. point.x = (round(resolution * point.x + alignStroke) - alignStroke) / resolution;
70. point.y = (round(resolution * point.y + alignStroke) - alignStroke) / resolution;
71. CGPathAddLineToPoint(path, NULL, point.x, point.y);
72. point = CGPointMake(15.0, 32.0);
73. point.x = (round(resolution * point.x + alignStroke) - alignStroke) / resolution;
74. point.y = (round(resolution * point.y + alignStroke) - alignStroke) / resolution;
75. controlPoint1 = CGPointMake(0.0, 25.229);
76. controlPoint1.x = (round(resolution * controlPoint1.x + alignStroke) - alignStroke) / resolution;
77. controlPoint1.y = (round(resolution * controlPoint1.y + alignStroke) - alignStroke) / resolution;
78. controlPoint2 = CGPointMake(6.771, 32.0);
79. controlPoint2.x = (round(resolution * controlPoint2.x + alignStroke) - alignStroke) / resolution;
80. controlPoint2.y = (round(resolution * controlPoint2.y + alignStroke) - alignStroke) / resolution;
81. CGPathAddCurveToPoint(path, NULL, controlPoint1.x, controlPoint1.y, controlPoint2.x, controlPoint2.y, point.x, point.y);
82. point = CGPointMake(295.0, 32.0);
83. point.x = (round(resolution * point.x + alignStroke) - alignStroke) / resolution;
84. point.y = (round(resolution * point.y + alignStroke) - alignStroke) / resolution;
85. CGPathAddLineToPoint(path, NULL, point.x, point.y);
86. CGPathCloseSubpath(path);
87. color = [UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:1.0];
88. [color setFill];
89. CGContextAddPath(context, path);
90. CGContextFillPath(context);
91. CGPathRelease(path);
92. }
93. 然后在你的controller中应用这个mask layer到你的UISearchBar
94. - (void)viewDidLoad {
95. [super viewDidLoad];
96. SearchMaskLayer *maskLayer = [[SearchMaskLayer alloc] init];
97. [maskLayer setFrame:CGRectMake(0, 0, 310, 34)];
98. [maskLayer setPosition:CGPointMake(162,21)];
99. [maskLayer setNeedsDisplay];
100. [self.searchBar.layer setNeedsDisplay];
101. [self.searchBar.layer setMask:maskLayer];
102. [maskLayer release];
103. }

2. 隐藏背景。非官方的方法。

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1. for (UIView *subview in searchBar.subviews) {
2. if ([subview isKindOfClass:NSClassFromString(@"UISearchBarBackground")]) {
3. [subview removeFromSuperview];
4. break;
5. }
6. }

3. 改变UISearchBar外观。 你可以子类化或category UISearchBar,然后实现两个方法，见代码。

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1. - (void)drawRect:(CGRect)rect {
2. //  UIImage *image = [UIImage imageNamed: @"background.png"];
3. //  [image drawInRect:rect];
4. }
5. - (void)drawLayer:(CALayer *)layer inContext:(CGContextRef)ctx {
6. UIImage *img = [UIImage imageNamed: @"background.png"];
7. UIImageView *v = [[[UIImageView alloc] initWithFrame:CGRectZero] autorelease];
8. [v setImage:img];
9. v.bounds = CGRectMake(0, 0, img.size.width, img.size.height);
10. NSLog([NSString stringWithFormat:@"%f:%f",img.size.width, img.size.height]);
11. NSArray *subs = self.subviews;
12. for (int i = 0; i < [subs count]; i++) {
13. id subv = [self.subviews objectAtIndex:i];
14. if ([subv isKindOfClass:NSClassFromString(@"UISearchBarBackground")])
15. {
16. CGRect viewRect = [subv frame];
17. [v setFrame:viewRect];
18. [self insertSubview:v atIndex:i];
19. }
20. }
21. [v setNeedsDisplay];
22. [v setNeedsLayout];
23. }

UISearchBar也是一个UIView,所以你可以像对待UIView一样对待它。