如何在viewWillDisappear上清除/清空粘貼板

Question

我使用UIPasteboard在兩個UITextView之間複製/粘貼文本。

代碼如下所示：

- (void)viewDidLoad { 
    [super viewDidLoad]; 
    pasteBoard = [UIPasteboard generalPasteboard]; //it is declared in .h as UIPasteboard *pasteBoard; 
} 

-(IBAction)doCopyBtn { 
    if (![toCopyTextView.text isEqualToString:@""]){ 
     pasteBoard.string = toCopyTextView.text; 
     NSLog(@"pasteb1 %@", pasteBoard.string); 
    } else { 
     NSLog (@"error! enter smth"); 
    } 
} 

-(IBAction)doPasteBtn { 
    if (![pasteBoard.string isEqualToString:@""]){ 
     toPasteTextView.text = pasteBoard.string; 
     NSLog(@"pasteb2 %@", pasteBoard.string); 
    } else { 
     NSLog (@"error! enter smth"); 
    } 
} 

即使這不能幫助（的NSLog返回：pasteb2 (null)）

-(void) viewWillDisappear:(BOOL)animated{ 
    [super viewWillDisappear:animated]; 
    [pasteBoard setString:@""]; 
} 

Answer 1

iOS版 - UIPasteboard

嘗試以下操作：

UIPasteboard *pb = [UIPasteboard generalPasteboard]; 
    [pb setValue:@"" forPasteboardType:UIPasteboardNameGeneral]; 

Arab_Geek的反應是正確的，但可用於可可（我懷疑你正在尋找的是iOS溶液）

Answer 2

OS X - NSPasteboard

在這裏，你去..

NSPasteboard *pb = [NSPasteboard generalPasteboard]; 
[pb declareTypes: [NSArray arrayWithObject:NSStringPboardType] owner: self]; 
[pb setString: @"" forType: NSStringPboardType]; 

Answer 3

將該值設置爲""會爲所有預期目的返回nil。但是，它會使粘貼板處於與粘貼操作之前稍微不同的狀態。

斯威夫特

let pb = self.pasteBoard() 
pb.setValue("", forPasteboardType: UIPasteboardNameGeneral) 

...不等同於UIPasteboard.removePasteboardWithName()。如果恢復UIPasteboard狀態令人擔憂（1），可以使用以下塊：

斯威夫特

let pb = self.pasteBoard() 

let items:NSMutableArray = NSMutableArray(array: pb.items) 
for object in pb.items { 
    if let aDictionary = object as? NSDictionary { 
     items.removeObject(aDictionary) 
    } 
} 
pb.items = items as [AnyObject] 

（1）中恢復狀態。