iOS中的键盘处理

• UIKeyboardWillShowNotification;
• UIKeyboardDidShowNotification;
• UIKeyboardWillHideNotification;
• UIKeyboardDidHideNotification;

iOS5.0以后

• UIKeyboardWillChangeFrameNotification
• UIKeyboardDidChangeFrameNotification

ChangeFrame 可用于监听键盘的显示和隐藏

- (void)viewDidLoad {
    [super viewDidLoad];
    
    // 发出通知监听键盘的显示或隐藏
    /*
     * UIKeyboardWillShowNotification;
     * UIKeyboardDidShowNotification;
     * UIKeyboardWillHideNotification;
     * UIKeyboardDidHideNotification;
     * UIKeyboardWillChangeFrameNotification
     * UIKeyboardDidChangeFrameNotification
     */
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillChangeFrame:) name:UIKeyboardWillChangeFrameNotification object:nil];
}

- (void)keyboardWillChangeFrame:(NSNotification *)note
{
    // 这里我们通过 note.userInfo 这个字典来取出对应的 key 进行操作
    NSLog(@"%@", note);
}

NSConcreteNotification 0x7fed62569a50 {name = UIKeyboardWillChangeFrameNotification; userInfo = {
    UIKeyboardAnimationCurveUserInfoKey = 7;
    UIKeyboardAnimationDurationUserInfoKey = "0.25";
    UIKeyboardBoundsUserInfoKey = "NSRect: {{0, 0}, {414, 271}}"; // 键盘尺寸
    UIKeyboardCenterBeginUserInfoKey = "NSPoint: {207, 871.5}";
    UIKeyboardCenterEndUserInfoKey = "NSPoint: {207, 600.5}";
    UIKeyboardFrameBeginUserInfoKey = "NSRect: {{0, 736}, {414, 271}}"; // 弹出前的 frame
    UIKeyboardFrameEndUserInfoKey = "NSRect: {{0, 465}, {414, 271}}"; // 弹出后的 frame
    UIKeyboardIsLocalUserInfoKey = 1;
}}