首先设置TextField 或 TextView的 delegate

/////UITextView

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text

{

    if ([text isEqualToString:@"\n"]) {

        NSLog("点击return");

        return NO;

    }

    return YES;

}

/////UITextField

- (BOOL)textFieldShouldReturn:(UITextField *)textField

{

    NSLog("点击return");

    return YES;

}