iOS8數字鍵盤左下角添加完成按鈕的核心代碼如下：

- (void)addDoneButtonToNumPadKeyboard
{
    UIButton *doneButton = [UIButton buttonWithType:UIButtonTypeCustom];
    if (systemVersion < 8.0){
        doneButton.frame = CGRectMake(0, 163, 106, 53);
    }else{
        doneButton.frame = CGRectMake(0, SCREEN_SIZE.height-53, 106, 53);
    }
    doneButton.tag = NUM_PAD_DONE_BUTTON_TAG;
    doneButton.adjustsImageWhenHighlighted = NO;
    [doneButton setTitle:@"完成" forState:UIControlStateNormal];
    [doneButton setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    [doneButton addTarget:self action:@selector(doneButton:) forControlEvents:UIControlEventTouchUpInside];
    
    NSArray *windowArr = [[UIApplication sharedApplication] windows];
    if (windowArr != nil && windowArr.count > 1){
        UIWindow *needWindow = [windowArr objectAtIndex:1];
        UIView *keyboard;
        for(int i = 0; i < [needWindow.subviews count]; i++) {
            keyboard = [needWindow.subviews objectAtIndex:i];
            NSLog(@"%@", [keyboard description]);
            if(([[keyboard description] hasPrefix:@" 1){
        UIWindow *needWindow = [windowArr objectAtIndex:1];
        UIView *keyboard;
        for(int i = 0; i < [needWindow.subviews count]; i++) {
            keyboard = [needWindow.subviews objectAtIndex:i];
            if(([[keyboard description] hasPrefix:@"












注：
1.iOS8之後，鍵盤view的description變為以
2.iOS8之後，鍵盤view的大小變成了整個屏幕的大小，所以需要對按鈕添加的位置進行適配。