输入号码 以银行卡号的形式显示出来，每隔四位数有空格的形式

- (void)viewDidLoad {

[superviewDidLoad];

[self.textFieldaddTarget:selfaction:@selector(textFieldChange:)forControlEvents:UIControlEventEditingChanged];

self.textField.keyboardType=UIKeyboardTypeNumberPad;

}

#pragma mark -输入框实时更新

- (void)textFieldChange:(UITextField*)textField

{

self.resultLab.text= [selfjointWithString:self.textField.text];

}

#pragma mark -拼接成中间有空格的字符串

- (NSString*)jointWithString:(NSString*)str{

NSString*getString =@"";

inta = (int)str.length/4;

intb = (int)str.length%4;

intc = a;

if(b>0){

c = a+1;

}else{

c = a;

}

for(inti =0; i

NSString*string =@"";

if(i == (c-1)){

if(b>0){

string = [strsubstringWithRange:NSMakeRange(4*(c-1), b)];

}else{

string = [strsubstringWithRange:NSMakeRange(4*i,4)];

}

}else{

string = [strsubstringWithRange:NSMakeRange(4*i,4)];

}

getString = [NSStringstringWithFormat:@"%@ %@",getString,string];

}

returngetString;

}