How can I programmatically check whether a keyboard is present in iOS app?
I need to check the condition of keyboard visibility in my iOS app.
Pseudocode:
if(keyboardIsPresentOnWindow) {
//Do action 1
}
else if (keyboardIsNotPresentOnWindow) {
//Do action 2
}
How can I check this condition?
drawnonward的代码非常接近，但与UIKit的命名空间相冲突，并且可以更容易使用。
@interface KeyboardStateListener : NSObject {
BOOL _isVisible;
}
+ (KeyboardStateListener *)sharedInstance;
@property (nonatomic, readonly, getter=isVisible) BOOL visible;
@end
static KeyboardStateListener *sharedInstance;
@implementation KeyboardStateListener
+ (KeyboardStateListener *)sharedInstance
{
return sharedInstance;
}
+ (void)load
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
sharedInstance = [[self alloc] init];
[pool release];
}
- (BOOL)isVisible
{
return _isVisible;
}
- (void)didShow
{
_isVisible = YES;
}
- (void)didHide
{
_isVisible = NO;
}
- (id)init
{
if ((self = [super init])) {
NSNotificationCenter *center = [NSNotificationCenter defaultCenter];
[center addObserver:self selector:@selector(didShow) name:UIKeyboardDidShowNotification object:nil];
[center addObserver:self selector:@selector(didHide) name:UIKeyboardWillHideNotification object:nil];
}
return self;
}
@end
…or take the easy way:
When you enter a textField, it becomes first responder and the keyboard appears. You can check the status of the keyboard with [myTextField isFirstResponder] . If it returns YES , then the the keyboard is active.
I think you need to use the notifications that are provided about the keyboard:
From: http://developer.apple.com/iphone/library/documentation/UIKit/Reference/UITextField_Class/Reference/UITextField.html
Keyboard Notifications
When the system shows or hides the keyboard, it posts several keyboard notifications. These notifications contain information about the keyboard, including its size, which you can use for calculations that involve moving views. Registering for these notifications is the only way to get some types of information about the keyboard. The system delivers the following notifications for keyboard-related events:
* UIKeyboardWillShowNotification
* UIKeyboardDidShowNotification
* UIKeyboardWillHideNotification
* UIKeyboardDidHideNotification
For more information about these notifications, see their descriptions in UIWindow Class Reference. For information about how to show and hide the keyboard, see Text and Web.
链接地址: http://www.djcxy.com/p/44218.html