iOS8 UIAlertView 推出页面后，键盘闪一下的问题，有需要的朋友可以参考下。

iOS8以后，当当前界面有UITextField输入框时，需要点击确定pop到上一个页面时，会出现pop界面后键盘出现又隐藏的问题，因为iOS8的SDK中，苹果提倡使用UIAlertController取代UIAlertView。

#define SYSTEM_VERSION [[UIDevice currentDevice].systemVersion floatValue]

if (SYSTEM_VERSION >= 8.0) {

    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:nil   message:@"提示文字" preferredStyle:UIAlertControllerStyleAlert];

    UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {

    [self.navigationController popToViewController:viewController animated:YES];

}];

    [alertController addAction:okAction];

    [self presentViewController:alertController animated:YES completion:nil];

} else {

    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"" message:@"提示文字" delegate:self cancelButtonTitle:@"确定" otherButtonTitles: nil];

    [alertView show];

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- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {

   [self.navigationController popToViewController:viewController animated:YES];

}