iOS开发之UIKeyboardTypeNumberPad数字键盘自定义按键

// 搜索按钮
_searchButton = [UIButton buttonWithType:UIButtonTypeCustom];
_searchButton.frame = CGRectMake(0, 163, 106, 53);
[_searchButton setTitle:@"搜索" forState:UIControlStateNormal];
[_searchButton setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
[_searchButton addTarget:self action:@selector(SearchButtonDidTouch:) forControlEvents:UIControlEventTouchUpInside]; 

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShowOnDelay:) name:UIKeyboardWillShowNotification object:nil];
- (void)keyboardWillShowOnDelay:(NSNotification *)notification {
[self performSelector:@selector(keyboardWillShow:) withObject:nil afterDelay:0];
}

- (void)keyboardWillShow:(NSNotification *)notification {
UIView *foundKeyboard = nil;
UIWindow *keyboardWindow = nil;
for (UIWindow *testWindow in [[UIApplication sharedApplication] windows]) {
if (![[testWindow class] isEqual:[UIWindow class]]) {
keyboardWindow = testWindow;
break;
}
}
if (!keyboardWindow) return;
for (__strong UIView *possibleKeyboard in [keyboardWindow subviews]) {
if ([[possibleKeyboard description] hasPrefix:@"<UIInputSetContainerView"]) {
for (__strong UIView *possibleKeyboard_2 in possibleKeyboard.subviews) {
if ([possibleKeyboard_2.description hasPrefix:@"<UIInputSetHostView"]) {
foundKeyboard = possibleKeyboard_2;
}
}
}
}
if (foundKeyboard) {
if ([[foundKeyboard subviews] indexOfObject:_searchButton] == NSNotFound) {
[foundKeyboard addSubview:_searchButton];
} else {
[foundKeyboard bringSubviewToFront:_searchButton];
}
}
}