隨機選擇的對象 -

Question

一個項目我已經改變我的背景顏色，三種顏色之一以下方法：

- (void) setBackgroundOfView { 
    // change the background color 
    UIColor *feijoa = [UIColor colorWithRed:0.565 green:0.82 blue:0.478 alpha:1]; /*#90d17a*/ 
    UIColor *turquoise = [UIColor colorWithRed:0.2 green:0.78 blue:0.773 alpha:1]; /*#33c7c5*/ 
    UIColor *lavendar = [UIColor colorWithRed:0.765 green:0.541 blue:0.898 alpha:1] /*#c38ae5*/ 
    UIColor *randomColor = random.choose(feijoa, turquoise, lavendar) // in pseudocode 
} 

是什麼正確的方式做random.choose(feijoa, turquoise, lavendar)？

Answer 1

您可以將顏色存儲到NSArray，並選擇其中一個隨機：

#include <stdlib.h> 

- (void) setBackgroundOfView { 
    // change the background color 
    UIColor *feijoa = [UIColor colorWithRed:0.565 green:0.82 blue:0.478 alpha:1]; /*#90d17a*/ 
    UIColor *turquoise = [UIColor colorWithRed:0.2 green:0.78 blue:0.773 alpha:1]; /*#33c7c5*/ 
    UIColor *lavendar = [UIColor colorWithRed:0.765 green:0.541 blue:0.898 alpha:1] /*#c38ae5*/ 

    NSArray *colors = @[feijoa, turquoise, lavendar]; 
    int index = arc4random_uniform(colors.count); 
    UIColor *randomColor = colors[index]; 
} 

Answer 2

我會成立三個數組。紅，綠，藍各一個。然後使用一個隨機數發生器來選擇一個索引。然後，你插入arrayRed [指數），arrayGreen [索引]，數組[藍] arrayBlue [索引]

UIColor *feijoa = [UIColor colorWithRed:arrayRed[index) green:arrayGreen[Index] blue:arrayBlue[Index] alpha:1]; 

UE中的arc4Random()函數生成索引。這種方法現在允許您輕鬆地向陣列或其他顏色添加更多顏色。

Answer 3

你有一組結果：

UIColor *feijoa = [UIColor colorWithRed:0.565 green:0.82 blue:0.478 alpha:1]; /*#90d17a*/ 
    UIColor *turquoise = [UIColor colorWithRed:0.2 green:0.78 blue:0.773 alpha:1]; /*#33c7c5*/ 
    UIColor *lavendar = [UIColor colorWithRed:0.765 green:0.541 blue:0.898 alpha:1] /*#c38ae5*/ 

而且你需要選擇一個隨機。把結果到一個數組：

NSArray *choices = @[feijoa, turquoise, lavender]; 

然後選擇一個隨機指數：

int index = arc4random() % ([choices count]); 

所以，選擇[指數]是你的項目