textFiled

当输入条太靠近文本框左边，可以设置一个leftView 来设置文本框

// 设置文本框左边的内容
    UIView *leftView = [[UIView alloc] init];
    leftView.frame = CGRectMake(0, 0, 10, 0);
    self.messageField.leftView = leftView;
    self.messageField.leftViewMode = UITextFieldViewModeAlways;