UIButton 定义中的'hides instance variable'警告

Question

我正在以编程方式将UIButton添加到datePicker：

 //today button
 CGRect todayButtonFrame = CGRectMake(180.0, 200.0, 40.0, 40.0);
 UIButton *todayButtonDatePicker = [[UIButton alloc]initWithFrame:todayButtonFrame];
 [todayButtonDatePicker addTarget:self action:@selector(myCustomFunction:) forControlEvents:UIControlEventTouchUpInside];
 [todayButtonDatePicker setBackgroundImage:[UIImage imageNamed:@"today.png"] forState:UIControlStateNormal];
[self.view addSubview: todayButtonDatePicker];

但是，编译器给了我一个警告：

Local declaration of 'todayButtonDatePicker' hides instance variable

Answer 1

如果要将UIButton保留为属性，请执行以下操作：

 //today button
 CGRect todayButtonFrame = CGRectMake(180.0, 200.0, 40.0, 40.0);
 self.todayButtonDatePicker = [[UIButton alloc]initWithFrame:todayButtonFrame];
 [self.todayButtonDatePicker addTarget:self action:@selector(myCustomFunction:)forControlEvents:UIControlEventTouchUpInside];
 [self.todayButtonDatePicker setBackgroundImage:[UIImage imageNamed:@"today.png"] forState:UIControlStateNormal];
 [self.view addSubview: self.todayButtonDatePicker];

或者，您可以删除该属性并仅使用局部变量。