ios - 如何在 objective-c 中禁用以编程方式创建的 UIBarButtonItem？

Question

我以编程方式创建了一个工具栏，并在工具栏中也以编程方式添加了四个 UIBarButtonItem。当 TextView 开始编辑时，此按钮将出现，如果 TextView 中没有文本清除按钮和翻译按钮将禁用。这是我的四个按钮创建代码。

UIToolbar* numberToolbar = [[UIToolbar alloc]initWithFrame:CGRectMake(0, 0, 320, 50)];
numberToolbar.backgroundColor = [UIColor lightGrayColor];

numberToolbar.items = [NSArray arrayWithObjects:
                       [[UIBarButtonItem alloc]initWithTitle:@"Hide" style:UIBarButtonItemStyleDone target:self action:@selector(cancelKeyboard)],
                       [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil],
                       [[UIBarButtonItem alloc]initWithTitle:@"Clear" style:UIBarButtonItemStyleDone target:self action:@selector(clearTextView)],
                       [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil],
                       [[UIBarButtonItem alloc]initWithTitle:@"Paste" style:UIBarButtonItemStyleDone target:self action:@selector(paste)],
                       [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil],
                       [[UIBarButtonItem alloc]initWithTitle:@"Translate" style:UIBarButtonItemStyleDone target:self action:@selector(translate)],
                       nil];
[numberToolbar sizeToFit];
_sorceTextview.inputAccessoryView = numberToolbar;
_sorceTextview.autocorrectionType = UITextAutocorrectionTypeNo;

现在我如何禁用清除和翻译按钮:

-(BOOL)textViewShouldBeginEditing:(UITextView *)textView {} 

方法？请帮忙。

Answer 1

为这些按钮使用实例变量。然后你可以设置enabled属性(property)根据需要。

@implementation MyViewController {
    UIBarButtonItem *_btnClear;
    UIBarButtonItem *_btnTranslate;
}

然后在您的工具栏设置代码中:

_btnClear = [[UIBarButtonItem alloc]initWithTitle:@"Clear" style:UIBarButtonItemStyleDone target:self action:@selector(clearTextView)];
_btnTranslate = [[UIBarButtonItem alloc]initWithTitle:@"Translate" style:UIBarButtonItemStyleDone target:self action:@selector(translate)];
UIBarButtonItem *flex = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];

numberToolbar.items = @[
                       [[UIBarButtonItem alloc]initWithTitle:@"Hide" style:UIBarButtonItemStyleDone target:self action:@selector(cancelKeyboard)],
                       flex,
                       _btnClear,
                       flex,
                       [[UIBarButtonItem alloc]initWithTitle:@"Paste" style:UIBarButtonItemStyleDone target:self action:@selector(paste)],
                       flex,
                       _btnTranslate
                       ];

然后在需要禁用的任何地方都可以执行以下操作:

_btnClear.enabled = NO;

并启用:

_btnClear.enabled = YES;