ios中UIButton選中狀態切換

關於UIButton的事件枚舉有許多，平時用的少所以很多的都不是很清楚，今天了解了下，看了以前的代碼，覺得在UIButton選中時操作寫了許多冗余代碼，而忽略了UIButton一個很重要的屬性，如下：

typedef NS_OPTIONS(NSUInteger, UIControlState) {
    UIControlStateNormal       = 0,
    UIControlStateHighlighted  = 1 << 0,                  // used when UIControl isHighlighted is set
    UIControlStateDisabled     = 1 << 1,
    UIControlStateSelected     = 1 << 2,                  // flag usable by app (see below)
#ifndef SDK_HIDE_TIDE
    UIControlStateFocused NS_ENUM_AVAILABLE_IOS(9_0) = 1 << 3, // Applicable only when the screen supports focus
#endif
    UIControlStateApplication  = 0x00FF0000,              // additional flags available for application use
    UIControlStateReserved     = 0xFF000000               // flags reserved for internal framework use
};

中的UIControlStateSelected表示是否選中，NO表示未選中，YES表示選中；

1.這是之前寫的：

創建UIButton，通過for 循環去創建

//頂部view的初始化
- (void)initTopView{

    topView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, kScreen_width, 40)];
    topFrame = topView.frame;
    topView.backgroundColor = [UIColor whiteColor];
    topView.alpha = .8;

    NSArray *titleArr = @[@"人氣",@"價格",@"桌數",@"優惠"];
    for (int i = 0; i < titleArr.count; i ++) {
        UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
        [btn setTitle:titleArr[i] forState:UIControlStateNormal];
        [btn setImage:[UIImage imageNamed:@"ph"] forState:UIControlStateNormal];
        [btn setTitleColor:[UIColor grayColor] forState:UIControlStateNormal];
        [btn setBackgroundImage:[UIImage imageNamed:@"button1"] forState:UIControlStateNormal];
        btn.titleLabel.font = [UIFont systemFontOfSize:12];
        btn.showsTouchWhenHighlighted = YES;
        btn.frame = CGRectMake(10 + i * ((kScreen_width - 50)/4 + 10) , 10, (kScreen_width - 50)/4, 25);
        //設置tag值
        btn.tag = i + 100;
        [btn addTarget:self action:@selector(choose:) forControlEvents:UIControlEventTouchUpInside];
        [topView addSubview:btn];
    }

    [self.view addSubview:topView];
}

添加響應事件：

//人氣、價格、作品數、優惠
- (void)choose:(UIButton *)sender{
    for (int i = 0; i < 4; i++) {
        UIButton *btn = (UIButton *)[[sender superview]viewWithTag:100 + i];
        [btn setSelected:NO];
        if (!btn.selected) {
            [btn setImage:[UIImage imageNamed:@"ph"] forState:UIControlStateNormal];
            [btn setTitleColor:[UIColor grayColor] forState:UIControlStateNormal];
            [btn setBackgroundImage:[UIImage imageNamed:@"button1"] forState:UIControlStateNormal];
        }
    }
    UIButton *button = (UIButton *)sender;
    [button setSelected:YES];
    [button setImage:[UIImage imageNamed:@"pho"] forState:UIControlStateNormal];
    [button setTitleColor:[UIColor colorWithRed:170.0/255 green:107.0/255 blue:208.0/255 alpha:1] forState:UIControlStateNormal];
    [button setBackgroundImage:[UIImage imageNamed:@"button2"] forState:UIControlStateNormal];
}

這種是最簡單的，相對也是最繁瑣的，多了很多不必要的冗余代碼，下面就讓我們看看改進的；

2.通過使用UIButton自己的一個selected屬性和normal屬性重構的，如下所示：

-(void)initUIButtonView{

    _titleArr = @[@"人氣",@"價格",@"桌數",@"優惠"];

    for (int i = 0; i < _titleArr.count; i ++) {
        UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
        btn.frame = CGRectMake(10 + i * ((kScreen_width - 50)/4 + 10) , 20, (kScreen_width - 50)/4, 25);
        [btn setTitle:_titleArr[i] forState:UIControlStateNormal];
        btn.titleLabel.font = [UIFont systemFontOfSize:12];
        btn.showsTouchWhenHighlighted = YES;
        //設置tag值
        btn.tag = i + 100;
        btn.selected = NO;
        [btn addTarget:self action:@selector(choose:) forControlEvents:UIControlEventTouchUpInside];
        [btn setTitleColor:[UIColor grayColor] forState:UIControlStateNormal];
        [btn setImage:[UIImage imageNamed:@"ph"] forState:UIControlStateNormal];
        [btn setBackgroundImage:[UIImage imageNamed:@"button1"] forState:UIControlStateNormal];

        [btn setTitleColor:[UIColor colorWithRed:170.0/255 green:107.0/255 blue:208.0/255 alpha:1] forState:UIControlStateSelected];
        [btn setImage:[UIImage imageNamed:@"pho"] forState:UIControlStateSelected];
        [btn setBackgroundImage:[UIImage imageNamed:@"button2"] forState:UIControlStateSelected];
        [self.view addSubview:btn];
    }

}

在創建的時候就給定了正常時候UIButton的樣式，和選中UIButton時的按鈕顏色，注意這里設置了默認的selected ＝ NO；和UIControlStateSelected

在給定按鈕選擇事件，設置對應selected的狀態值，如下所示：

//人氣、價格、作品數、優惠
- (void)choose:(UIButton *)sender{
    for (int i = 0; i < _titleArr.count; i++) {
        UIButton *btn = (UIButton *)[[sender superview]viewWithTag:100 + i];
        [btn setSelected:NO];
    }
    UIButton *button = (UIButton *)sender;
    [button setSelected:YES];
}

這樣看上去，第二種方法，是不是比第一種方法更簡單明了，去除了相關的冗余代碼的，效果如下所示

注：改進，上面的我們可以在不同的按鈕上面切換狀態，但在同一個按鈕上面點擊多次狀態不會改變，針對上述問題做了些許的改動，其實主要是在點擊事件里面，判斷當前按鈕的狀態去改變，代碼如下：

//人氣、價格、作品數、優惠
- (void)choose:(UIButton *)sender{
    for (int i = 0; i < _titleArr.count; i++) {
        UIButton *btn = (UIButton *)[[sender superview]viewWithTag:100 + i];
        //選中當前按鈕時
        if (sender.tag == btn.tag) {

            sender.selected = !sender.selected;
        }else{

            [btn setSelected:NO];
        }
    }

}

效果圖如下所示：