ios - 附加字符串不起作用

Question

我正在尝试这段代码...

NSString *tileString = [[NSString alloc] init];    

for (int i = 0; i < [[GameP objectForKey:@"groundMap"] length]; i += 5) {

            tileString = [[GameP objectForKey:@"groundMap"] substringWithRange:NSMakeRange(i, 5)];

            [tileString stringByAppendingString:@"0000"];

            [sharedInstance.groundMap addObject:tileString];
        }

来自对象的 5 个字符字符串是“t0001”，所以我想以“t0001000”结束，但它不起作用，当我检查 sharedInstance.groundMap 时，数组中的所有字符串仍然是“t0001”

我应该改用 NSMutableString 吗？

Answer 1

您没有分配结果。改变这个：

[tileString stringByAppendingString:@"0000"];

至：

titleString = [tileString stringByAppendingString:@"0000"];

你也可以做更多的清理工作：

for (int i = 0; i < [[GameP objectForKey:@"groundMap"] length]; i += 5) {
    NSString *tileString = [[GameP objectForKey:@"groundMap"] substringWithRange:NSMakeRange(i, 5)];
    titleString = [tileString stringByAppendingString:@"0000"];
    [sharedInstance.groundMap addObject:tileString];
}