UIControlState在繼承UIButton的時候獲取值的名稱是什麼？

Question

我是繼承UIButton。 但我需要知道狀態該按鈕在繪製按鈕的顏色向上或向下：

- (void)drawRect:(CGRect)rect{ 
    if (state==UIControlStateNormal) { 
     //draw rect RED 
    } 
    if (state==UIControlEventTouchDown) 
     //draw rect BLUE 
    } 
} 

Answer 1

你甚至嘗試在看文檔？

1. 轉到UIButton Reference
2. 檢查屬性
3. 沒有明顯
4. 看看UIButton有超
5. 轉到UIControl Reference - UIButton的超
6. 檢查屬性
7. 哦，看有是state財產

---

更新

接受的答案是不正確略，並可能導致一些煩人的臭蟲很難追查。

爲UIControl頭聲明state作爲

@property(nonatomic,readonly) UIControlState state;     // could be more than one state (e.g. disabled|selected). synthesized from other flags. 

現在擡頭看怎麼UIControlState定義，我們看到

enum { 
    UIControlStateNormal  = 0,      
    UIControlStateHighlighted = 1 << 0,     // used when UIControl isHighlighted is set 
    UIControlStateDisabled  = 1 << 1, 
    UIControlStateSelected  = 1 << 2,     // flag usable by app (see below) 
    UIControlStateApplication = 0x00FF0000,    // additional flags available for application use 
    UIControlStateReserved  = 0xFF000000    // flags reserved for internal framework use 
}; 
typedef NSUInteger UIControlState; 

因此當你正在處理一個位掩碼您應檢查適當地說，例如

if (self.state & UIControlStateNormal) { ... } 

---

更新2

你可以通過繪製成圖像，然後設置圖像爲背景，例如做

- (void)clicked:(UIButton *)button; 
{ 
    UIGraphicsBeginImageContext(button.frame.size); 

    // Draw gradient 

    UIImage *gradient = UIGraphicsGetImageFromCurrentImageContext(); 

    UIGraphicsEndImageContext(); 

    [button setBackgroundImage:image forState:UIControlStateNormal]; 
} 

Answer 2

由於state是一個屬性，你可以使用self.state訪問它。

更新：

查看下一個答案的更新。

Answer 3

重新繪製矩形，我這樣做...

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{ 
    myState = 1; 
    [self setNeedsDisplay]; 
} 

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{ 
    myState = 0; 
    [self setNeedsDisplay]; 
} 


- (void)drawRect:(CGRect)rect 
{ 
    // Drawing code 
    NSLog(@"drawRect state: %d", self.state); 
    NSLog(@"rect %@", NSStringFromCGRect(self.frame)); 
    c = UIGraphicsGetCurrentContext(); 

    if (myState==0){ 
    ///////// plot border ///////////// 
    CGContextBeginPath(c); 
    CGContextSetLineWidth(c, 2.0); 
    CGContextMoveToPoint(c, 1, 1); 
    CGContextAddLineToPoint(c, 1, 20); 
    CGContextAddLineToPoint(c, 299, 20); 
    CGContextAddLineToPoint(c, 299, 1); 
    CGContextSetRGBFillColor(c, 0.0, 0.0, 1.0, 1.0); 
    CGContextFillPath(c); 
    CGContextClosePath(c); 
    CGContextStrokePath(c); 
    }else{ 
    CGContextBeginPath(c); 
    CGContextSetLineWidth(c, 2.0); 
    CGContextMoveToPoint(c, 1, 20); 
    CGContextAddLineToPoint(c, 1, 40); 
    CGContextAddLineToPoint(c, 299, 40); 
    CGContextAddLineToPoint(c, 299, 20); 
    CGContextSetRGBFillColor(c, 1.0, 0.0, 1.0, 1.0); 
    CGContextFillPath(c); 
    CGContextClosePath(c); 
    CGContextStrokePath(c); 
    } 
}