iOS开发初级（一、基础002）

UILable、UIImageView、UIButton的拓展：
三个控件，当显示文字时，使用UILable，当显示图片时，使用UIImageView，当带有点击事件时，使用UIButton。对于UIButton的拓展，需要知道：

    [button setTitle:@"我是按钮" forState:UIControlStateNormal];//设置button的文字
    [button setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];//设置button的文字颜色

上面的代码，已经介绍了，现在，拓展一下按钮控件UIButton的状态（state）：

typedef NS_OPTIONS(NSUInteger, UIControlState) {
    UIControlStateNormal       = 0,//一般状态
    UIControlStateHighlighted  = 1 << 0,                  // 高亮状态used when UIControl isHighlighted is set
    UIControlStateDisabled     = 1 << 1,//不可以状态
    UIControlStateSelected     = 1 << 2,                  // 选中的状态 flag usable by app (see below)
    UIControlStateFocused NS_ENUM_AVAILABLE_IOS(9_0) = 1 << 3, // Applicable only when the screen supports focus
    UIControlStateApplication  = 0x00FF0000,              // additional flags available for application use
    UIControlStateReserved     = 0xFF000000               // flags reserved for internal framework use
};

代码练习：

@interface ViewController ()
{
    UIButton *_buttonStateNormal;//声明一个变量，该类的全局变量 _buttonStateNormal
    UIButton *_buttonStateHighlighted;//声明一个变量，该类的全局变量_buttonStateHighlighted
    UIButton *_buttonStateSelected ;//声明一个变量，该类的全局变量_buttonStateSelected
    UIButton *_buttonStateDisabled;//声明一个变量，该类的全局变量_buttonStateDisabled
}
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    _buttonStateNormal = [UIButton buttonWithType:UIButtonTypeCustom];//使用类方法初始化按钮
    _buttonStateNormal.frame = CGRectMake(20.0, 20.0, 80.0, 40.0);
    _buttonStateNormal.backgroundColor = [UIColor orangeColor];
    [_buttonStateNormal setTitle:@"按钮" forState:UIControlStateNormal];
    [_buttonStateNormal setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    [_buttonStateNormal setBackgroundImage:[UIImage imageNamed:@"bg"] forState:UIControlStateNormal];//设置背景图片
    [self.view addSubview:_buttonStateNormal];
    
    
    _buttonStateHighlighted = [UIButton buttonWithType:UIButtonTypeCustom];//使用类方法初始化按钮
    _buttonStateHighlighted.frame = CGRectMake(20.0, 70, 80.0, 40.0);
    _buttonStateHighlighted.backgroundColor = [UIColor orangeColor];
    [_buttonStateHighlighted setTitle:@"按钮" forState:UIControlStateNormal];
    [_buttonStateHighlighted setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    [_buttonStateHighlighted setTitle:@"按钮Highlighted" forState:UIControlStateHighlighted];
    [_buttonStateHighlighted setTitleColor:[UIColor greenColor] forState:UIControlStateHighlighted];
    [self.view addSubview:_buttonStateHighlighted];

    _buttonStateSelected = [UIButton buttonWithType:UIButtonTypeCustom];//使用类方法初始化按钮
    _buttonStateSelected.frame = CGRectMake(20.0, 120, 80.0, 40.0);
    _buttonStateSelected.backgroundColor = [UIColor orangeColor];
    [_buttonStateSelected setTitle:@"按钮" forState:UIControlStateNormal];
    [_buttonStateSelected setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    [_buttonStateSelected setTitle:@"按钮Selected" forState:UIControlStateSelected];
    [_buttonStateSelected setTitleColor:[UIColor greenColor] forState:UIControlStateSelected];
    [_buttonStateSelected addTarget:self action:@selector(buttonSelectedClick:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:_buttonStateSelected];

    _buttonStateDisabled = [UIButton buttonWithType:UIButtonTypeCustom];//使用类方法初始化按钮
    _buttonStateDisabled.frame = CGRectMake(20.0, 170.0, 80.0, 40.0);
    _buttonStateDisabled.backgroundColor = [UIColor orangeColor];
    [_buttonStateDisabled setTitle:@"按钮" forState:UIControlStateNormal];
    [_buttonStateDisabled setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    [_buttonStateDisabled setTitle:@"按钮Disabled" forState:UIControlStateDisabled];
    [_buttonStateDisabled setTitleColor:[UIColor greenColor] forState:UIControlStateDisabled];
    [_buttonStateDisabled addTarget:self action:@selector(buttonDisableClick:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:_buttonStateDisabled];
    
    // Do any additional setup after loading the view, typically from a nib.
}


-(void)buttonSelectedClick:(UIButton *)sender {
    sender.selected = !sender.selected;
}
-(void)buttonDisableClick:(UIButton *)sender{
    [sender setEnabled:NO];//设置为不可点击UIControlStateDisabled

}

@end

运行效果：（以及点击后效果）

屏幕快照 2018-07-19 下午2.48.22.png 屏幕快照 2018-07-19 下午2.48.34.png

UIButton的响应事件event(事件)：
代码：

[_buttonStateSelected addTarget:self action:@selector(buttonSelectedClick:) forControlEvents:UIControlEventTouchUpInside];

event的几种枚举：

typedef NS_OPTIONS(NSUInteger, UIControlEvents) {
    UIControlEventTouchDown                                         = 1 <<  0,      // 点击下去响应on all touch downs
    UIControlEventTouchDownRepeat                                   = 1 <<  1,      // 重复点击响应on multiple touchdowns (tap count > 1)
    UIControlEventTouchDragInside                                   = 1 <<  2,//向内部拖拽响应
    UIControlEventTouchDragOutside                                  = 1 <<  3,//向外部拖拽响应
    UIControlEventTouchDragEnter                                    = 1 <<  4,
    UIControlEventTouchDragExit                                     = 1 <<  5,
    UIControlEventTouchUpInside                                     = 1 <<  6,//点击下去响应
    UIControlEventTouchUpOutside                                    = 1 <<  7,
    UIControlEventTouchCancel                                       = 1 <<  8,

    UIControlEventValueChanged                                      = 1 << 12,     // sliders, etc.
    UIControlEventPrimaryActionTriggered NS_ENUM_AVAILABLE_IOS(9_0) = 1 << 13,     // semantic action: for buttons, etc.

    UIControlEventEditingDidBegin                                   = 1 << 16,     // UITextField
    UIControlEventEditingChanged                                    = 1 << 17,
    UIControlEventEditingDidEnd                                     = 1 << 18,
    UIControlEventEditingDidEndOnExit                               = 1 << 19,     // 'return key' ending editing

    UIControlEventAllTouchEvents                                    = 0x00000FFF,  // for touch events
    UIControlEventAllEditingEvents                                  = 0x000F0000,  // for UITextField
    UIControlEventApplicationReserved                               = 0x0F000000,  // range available for application use
    UIControlEventSystemReserved                                    = 0xF0000000,  // range reserved for internal framework use
    UIControlEventAllEvents                                         = 0xFFFFFFFF
};