首先必須知道鍵盤出現的時間點，在 viewDidLoad 的函式中加入：
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
這樣就可以註冊一個observer，在鍵盤要出現的時候會呼叫我們定義的keyboardWillShow method：
- (void)keyboardWillShow:(NSNotification *)note {
[self performSelector:@selector(removeBar) withObject:nil afterDelay:0];
}
這邊需要一個短暫的delay再去呼叫removeBar，因為在收到的當下鍵盤的view還沒實際出現。不過這樣一來就有可能執行removeBar的時候鍵盤其實還沒出現（我反覆測試了很多次，都還沒遇到有失敗的case）。
實際上真正移除的code如下，先找到非UI-Window的keyboardWindow，之後在從keyboard的subviews裡面找到鍵盤上方的按鈕subview：
- (void)removeBar {
// Locate non-UIWindow.
UIWindow *keyboardWindow = nil;
for (UIWindow *testWindow in [[UIApplication sharedApplication] windows]) {
if (![[testWindow class] isEqual:[UIWindow class]]) {
keyboardWindow = testWindow;
break;
}
}
// Locate UIWebFormView.
for (UIView *possibleFormView in [keyboardWindow subviews]) {
// iOS 5 sticks the UIWebFormView inside a UIPeripheralHostView.
if ([[possibleFormView description] rangeOfString:@"UIPeripheralHostView"].location != NSNotFound) {
for (UIView *subviewWhichIsPossibleFormView in [possibleFormView subviews]) {
if ([[subviewWhichIsPossibleFormView description] rangeOfString:@"UIWebFormAccessory"].location != NSNotFound) {
[subviewWhichIsPossibleFormView removeFromSuperview];
}
}
}
}
}
此文參考：A one stop blog for iPhone Application Development
