Objectivec 反转 NSString 文本

发布于07月17日

我已经在谷歌上搜索了这么多关于如何做到这一点，但我该如何反转一个字符串呢？例如:hi会变成:ih

我正在寻找最简单的方法.

谢谢

@文斯一世提出了这个方法:

- (IBAction)doneKeyboard {

// first retrieve the text of textField1
NSString *myString = field1.text;
NSMutableString *reversedString = [NSMutableString string];
NSUInteger charIndex = 0;
while(myString && charIndex < [myString length]) {
    NSRange subStrRange = NSMakeRange(charIndex, 1);
    [reversedString appendString:[myString substringWithRange:subStrRange]];
    charIndex++;
}
// reversedString is reversed, or empty if myString was nil
field2.text = reversedString;
}

我把这个方法连接到了textfield1的DiEndonexit上.当我单击"完成"按钮时，它不会反转文本，UILabel只显示我输入的UITextField文本.怎么了？

推荐答案

编写一个简单的循环来实现这一点:

// myString is "hi"
NSMutableString *reversedString = [NSMutableString string];
NSInteger charIndex = [myString length];
while (charIndex > 0) {
    charIndex--;
    NSRange subStrRange = NSMakeRange(charIndex, 1);
    [reversedString appendString:[myString substringWithRange:subStrRange]];
}
NSLog(@"%@", reversedString); // outputs "ih"

In your case:

// first retrieve the text of textField1
NSString *myString = textField1.text;
NSMutableString *reversedString = [NSMutableString string];
NSInteger charIndex = [myString length];
while (myString && charIndex > 0) {
    charIndex--;
    NSRange subStrRange = NSMakeRange(charIndex, 1);
    [reversedString appendString:[myString substringWithRange:subStrRange]];
}
// reversedString is reversed, or empty if myString was nil
textField2.text = reversedString;