我们如何使用HID键盘按键拍摄iphone / ipad设备的屏幕截图？

Question

我想创建一个可以帮助我们使用HID键盘按键进行屏幕截图的应用程序，但是我不知道如何检测HID键盘按键。请事先帮助我，谢谢

Answer 1

i dont know about that special keyboard but using of this code you can take a scree shot from your application. You can put this code in button action and check it's working but about your keyboard i have no idea.

UIGraphicsBeginImageContext(self.window.bounds.size);
[self.window.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
NSData * data = UIImagePNGRepresentation(image);
[data writeToFile:@"foo.png" atomically:YES];

UPDATE April 2011: for retina display, change the first line into this:

if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)])
UIGraphicsBeginImageContextWithOptions(self.window.bounds.size, NO, [UIScreen mainScreen].scale);
else
UIGraphicsBeginImageContext(self.window.bounds.size);

Answer 2

You can use Keyboard notification

#pragma mark - Keyboard notification
- (void)registerForKeyboardNotifications
{    
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardWillBeShown:)
                                                 name:UIKeyboardWillShowNotification object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardWillBeHidden:)
                                                 name:UIKeyboardWillHideNotification object:nil];
}

-(void)keyboardWillBeShown:(NSNotification*)aNotification
{

}
- (void)keyboardWillBeHidden:(NSNotification*)aNotification
{

}