如何响应外部键盘箭头键？

Question

我知道这已被问及之前，我看到的唯一答案是“不需要外接键盘，因为它违背了UI准则”。但是，我想使用这样的脚踏板：http://www.bilila.com/page_turner_for_ipad在我的应用程序中的页面之间切换（除了滑动）。此页面翻转器模拟键盘并使用向上/向下箭头键。

所以这里是我的问题：我如何回应这些箭头键事件？它必须是可能的，因为其他应用程序管理，但我画空白。

Answer 1

对于那些在iOS 7下寻找解决方案的用户，有一个名为keyCommands的新UIResponder属性。创建UITextView的子类并执行如下的keyCommands ...

@implementation ArrowKeyTextView 

- (id) initWithFrame: (CGRect) frame 
{ 
    self = [super initWithFrame:frame]; 
    if (self) { 
    } 
    return self; 
} 

- (NSArray *) keyCommands 
{ 
    UIKeyCommand *upArrow = [UIKeyCommand keyCommandWithInput: UIKeyInputUpArrow modifierFlags: 0 action: @selector(upArrow:)]; 
    UIKeyCommand *downArrow = [UIKeyCommand keyCommandWithInput: UIKeyInputDownArrow modifierFlags: 0 action: @selector(downArrow:)]; 
    UIKeyCommand *leftArrow = [UIKeyCommand keyCommandWithInput: UIKeyInputLeftArrow modifierFlags: 0 action: @selector(leftArrow:)]; 
    UIKeyCommand *rightArrow = [UIKeyCommand keyCommandWithInput: UIKeyInputRightArrow modifierFlags: 0 action: @selector(rightArrow:)]; 
    return [[NSArray alloc] initWithObjects: upArrow, downArrow, leftArrow, rightArrow, nil]; 
} 

- (void) upArrow: (UIKeyCommand *) keyCommand 
{ 

} 

- (void) downArrow: (UIKeyCommand *) keyCommand 
{ 

} 

- (void) leftArrow: (UIKeyCommand *) keyCommand 
{ 

} 

- (void) rightArrow: (UIKeyCommand *) keyCommand 
{ 

} 

Answer 2

Sorted！我简单地使用一个1x1px文本查看和使用委托方法textViewDidChangeSelection:

编辑：对于iOS 6我不得不改变文本视图到50x50px（或至少足以实际显示文本）这个工作

当踏板断开连接时，我也设法抑制了屏幕键盘。

这是我的代码在viewDidLoad中：

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillAppear:) name:UIKeyboardWillShowNotification object:nil]; 
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillDisappear:) name:UIKeyboardWillHideNotification object:nil]; 

UITextView *hiddenTextView = [[UITextView alloc] initWithFrame:CGRectMake(0, 0, 50, 50)]; 
[hiddenTextView setHidden:YES]; 
hiddenTextView.text = @"aa"; 
hiddenTextView.delegate = self; 
hiddenTextView.selectedRange = NSMakeRange(1, 0); 
[self.view addSubview:hiddenTextView]; 

[hiddenTextView becomeFirstResponder]; 
if (keyboardShown) 
    [hiddenTextView resignFirstResponder]; 

keyboardShown被声明为我的头文件bool。

然后将这些方法：

- (void)textViewDidChangeSelection:(UITextView *)textView { 

    /******TEXT FIELD CARET CHANGED******/ 

    if (textView.selectedRange.location == 2) { 

     // End of text - down arrow pressed 
     textView.selectedRange = NSMakeRange(1, 0); 

    } else if (textView.selectedRange.location == 0) { 

     // Beginning of text - up arrow pressed 
     textView.selectedRange = NSMakeRange(1, 0); 

    } 

    // Check if text has changed and replace with original 
    if (![textView.text isEqualToString:@"aa"]) 
     textView.text = @"aa"; 
} 

- (void)keyboardWillAppear:(NSNotification *)aNotification { 
    keyboardShown = YES; 
} 

- (void)keyboardWillDisappear:(NSNotification *)aNotification { 
    keyboardShown = NO; 
} 

我希望这个代码可以帮助别人谁是寻找一个解决这个问题。随意使用它。