iOS中如何實現TextView僅可粘貼不可輸入的功能

思路來源http://stackoverflow.com/questions/1920541/enable-copy-and-paste-on-uitextfield-without-making-it-editable

注意：此方法僅支持iOS6.0或者更新，5.0系統因粘貼觸發機制不一樣，若是設置editable爲NO，那麼長按時並不會觸發-- (BOOL)canPerformAction:(SEL)action withSender:(id)sender方法。如需支持6.0如下系統，請特別注意。

首先從UITextView繼承一個子類並重寫如下方法：

- (BOOL)canPerformAction:(SEL)action withSender:(id)sender
{
    if (action == @selector(paste:)) {
        return YES;
    }else{
        return [super canPerformAction:action withSender:sender];
    }
}

- (BOOL)canBecomeFirstResponder
{
    return YES;
}

- (BOOL)becomeFirstResponder
{
    if ([super becomeFirstResponder]) {
        return YES;
    }
    return NO;
}

- (void)paste:(id)sender
{
    UIPasteboard *board = [UIPasteboard generalPasteboard];
    self.text = board.string;
    [self resignFirstResponder];
}

而後在實例化時將textView的eidable屬性設爲NO便可；