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textfield有个属性leftview,设置一个只有宽度的leftView.然后需要将leftViewMode设置为UITextFieldViewModeAlways.因为默认textfield.leftView是不显示的.
//设置文本框左边的view
UITextField *textField = [[UITextField alloc]init];
textField.frame = CGRectMake(50, 50, 300, 30);
[self.view addSubview:textField];
textField.leftView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 6, 0)];
//设置显示模式为永远显示(默认不显示)
textField.leftViewMode = UITextFieldViewModeAlways;