014改变背景颜色

效果如下：

ViewController.h

 1 #import <UIKit/UIKit.h>
 2
 3 @interface ViewController : UIViewController {
 4     @private
 5     UILabel *lblMessage;
 6     CGFloat colorRed;
 7     CGFloat colorGreen;
 8     CGFloat colorBlue;
 9 }
10
11 @end

ViewController.m

 1 #import "ViewController.h"
 2
 3 @interface ViewController ()
 4 - (void)redDidPush;
 5 - (void)greenDidPush;
 6 - (void)blueDidPush;
 7 - (void)changeLabelColor:(CGFloat*)pColor;
 8 @end
 9
10 @implementation ViewController
11 #pragma mark - Start Implementation For Methods
12 - (void)viewDidLoad {
13     [super viewDidLoad];
14     colorRed = 0.0;
15     colorGreen = 0.0;
16     colorBlue = 0.0;
17     CGPoint newPoint = self.view.center;
18
19     //追加Label标签
20     lblMessage = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 320, 200)];
21     lblMessage.textAlignment = NSTextAlignmentCenter;
22     lblMessage.center = newPoint;
23     lblMessage.textColor = [UIColor whiteColor];
24     lblMessage.text = @"染上新的颜色吧...";
25     lblMessage.backgroundColor = [[UIColor alloc] initWithRed:colorRed green:colorGreen blue:colorBlue alpha:1.0];
26     //设置Label标签的圆角和边框
27     lblMessage.layer.cornerRadius = 8.0;
28     lblMessage.layer.masksToBounds = YES;
29     lblMessage.layer.borderColor = [UIColor yellowColor].CGColor;
30     lblMessage.layer.borderWidth = 2.0;
31     [self.view addSubview:lblMessage];
32
33     //追加红色按钮
34     UIButton *btnRed = [UIButton buttonWithType:UIButtonTypeRoundedRect];
35     btnRed.frame = CGRectMake(0, 0, 50, 40);
36     newPoint.x -= (btnRed.frame.size.width + 10);
37     newPoint.y = self.view.frame.size.height - 70;
38     btnRed.center = newPoint;
39     btnRed.backgroundColor = [UIColor grayColor];
40     [btnRed setTitle:@"红" forState:UIControlStateNormal];
41     [btnRed setTitleColor:[UIColor redColor] forState:UIControlStateNormal];
42     [btnRed addTarget:self action:@selector(redDidPush) forControlEvents:UIControlEventTouchUpInside];
43     [self.view addSubview:btnRed];
44
45     //追加绿色按钮
46     UIButton *btnGreen = [UIButton buttonWithType:UIButtonTypeRoundedRect];
47     btnGreen.frame = btnRed.frame;
48     newPoint.x += (btnRed.frame.size.width + 5);
49     btnGreen.center = newPoint;
50     btnGreen.backgroundColor = [UIColor grayColor];
51     [btnGreen setTitle:@"绿" forState:UIControlStateNormal];
52     [btnGreen setTitleColor:[UIColor greenColor] forState:UIControlStateNormal];
53     [btnGreen addTarget:self action:@selector(greenDidPush) forControlEvents:UIControlEventTouchUpInside];
54     [self.view addSubview:btnGreen];
55
56
57     //追加蓝色按钮
58     UIButton *btnBlue = [UIButton buttonWithType:UIButtonTypeRoundedRect];
59     btnBlue.frame = btnRed.frame;
60     newPoint.x += (btnRed.frame.size.width + 5);
61     btnBlue.center = newPoint;
62     btnBlue.backgroundColor = [UIColor grayColor];
63     [btnBlue setTitle:@"蓝" forState:UIControlStateNormal];
64     [btnBlue setTitleColor:[UIColor blueColor] forState:UIControlStateNormal];
65     [btnBlue addTarget:self action:@selector(blueDidPush) forControlEvents:UIControlEventTouchUpInside];
66     [self.view addSubview:btnBlue];
67 }
68
69 - (void)didReceiveMemoryWarning {
70     [super didReceiveMemoryWarning];
71     // Dispose of any resources that can be recreated.
72 }
73
74 #pragma mark - Private Methods
75 - (void)redDidPush {
76     [self changeLabelColor:&colorRed];
77 }
78
79 - (void)greenDidPush {
80     [self changeLabelColor:&colorGreen];
81 }
82
83 - (void)blueDidPush {
84     [self changeLabelColor:&colorBlue];
85 }
86
87 - (void)changeLabelColor:(CGFloat *)pColor {
88     if (pColor) {
89         if (*pColor > 0.99) {
90             *pColor = 0.0;
91         } else {
92             *pColor += 0.1;
93         }
94         lblMessage.backgroundColor = [[UIColor alloc] initWithRed:colorRed green:colorGreen blue:colorBlue alpha:1.0];
95     }
96 }
97 @end