OC自带的Alert弹窗

一，UIAlertController的使用：

UIAlertController是一个控制器，所以需要按照控制器的方式进行显示：

- (void)presentViewController:(UIViewController *)viewControllerToPresent animated: (BOOL)flag completion:(void (^ __nullable)(void))completion；

手动销毁的时候也需要按照控制器的方式进行退出：

- (void)dismissViewControllerAnimated: (BOOL)flag completion: (void (^ __nullable)(void))completion

下面将详细介绍一下这个控制器的使用：

1，创建控制器

//在这里控制alert的样式是UIAlertControllerStyleAlert还是UIAlertControllerStyleActionSheet
UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"alertController" message:@"This is an alertController" preferredStyle:UIAlertControllerStyleAlert];

2，添加按钮，并为按钮设置样式//可以添加很多个，随意，通过后面的block进行回调，无需代理方法

//这一步是为了防止循环引用
__weak typeof(alertController) weakAlert = alertController;

UIAlertAction *actionDefault = [UIAlertAction actionWithTitle:@"action Default" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
    NSLog(@"action Default did clicked");
    //为了防止循环引用，在这里需要进行弱引用设置，下面如果有用到alertController的也需要做相同的处理
    NSString *text = weakAlert.textFields.lastObject.text;
    NSLog(@"%@",text);
}];
[alertController addAction:actionDefault];

UIAlertAction *actionCancel = [UIAlertAction actionWithTitle:@"action cancel" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {
    NSLog(@"action cancel did clicked");
}];
[alertController addAction:actionCancel];

UIAlertAction *actionDestructive = [UIAlertAction actionWithTitle:@"action destructive" style:UIAlertActionStyleDestructive handler:^(UIAlertAction * _Nonnull action) {
    NSLog(@"action destructive did clicked");
}];
[alertController addAction:actionDestructive];

UIAlertAction *actionDestructive01 = [UIAlertAction actionWithTitle:@"action destructive 01" style:UIAlertActionStyleDestructive handler:^(UIAlertAction * _Nonnull action) {
    NSLog(@"action destructive 01 did clicked");
}];
[alertController addAction:actionDestructive01];

3，添加文本框//可以添加很多个，随意，文本框的属性可以在后面的block中设置

[alertController addTextFieldWithConfigurationHandler:^(UITextField * _Nonnull textField) {
    
}];
[alertController addTextFieldWithConfigurationHandler:^(UITextField * _Nonnull textField) {
    
}];
[alertController addTextFieldWithConfigurationHandler:^(UITextField * _Nonnull textField) {
    textField.text = @"zhangdanfeng";
}];

4，显示控制器

[self presentViewController:alertController animated:YES completion:^{
    
}];

二，UIAlertView的使用：

1，创建view：

//你可以在创建的时候决定上面有多少个按钮
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Alert" message:@"This is an alert" delegate:self cancelButtonTitle:@"cancel" otherButtonTitles:@"Are you sure?",@"ddd",@"fad", nil];
//创建后如果想要增加按钮也可以：（按钮如果太多，会通过scroll方式展示）
[alertView addButtonWithTitle:@"zhhhhhh"];

2，设置UIAlertView样式：（共有四种样式）


//    UIAlertViewStyleDefault = 0,
//    UIAlertViewStyleSecureTextInput,
//    UIAlertViewStylePlainTextInput,
//    UIAlertViewStyleLoginAndPasswordInput
alertView.alertViewStyle = UIAlertViewStyleLoginAndPasswordInput;

3，设置代理<UIAlertViewDelegate>，然后展示出来

//其实在创建的时候已经设置过代理了，这里不需要再重新设置了
//    alertView.delegate = self;
[alertView show];

4，实现代理方法：

//代理方法

// Called when a button is clicked. The view will be automatically dismissed after this call returns
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{
    NSLog(@"%ld",(long)buttonIndex);
}

// Called when we cancel a view (eg. the user clicks the Home button). This is not called when the user clicks the cancel button.
// If not defined in the delegate, we simulate a click in the cancel button
- (void)alertViewCancel:(UIAlertView *)alertView{
    NSLog(@"break");
}

- (void)willPresentAlertView:(UIAlertView *)alertView{// before animation and showing view
    NSLog(@"%s",__func__);
}
- (void)didPresentAlertView:(UIAlertView *)alertView{// after animation
    NSLog(@"%s",__func__);
}

- (void)alertView:(UIAlertView *)alertView willDismissWithButtonIndex:(NSInteger)buttonIndex{// before animation and hiding view
    NSLog(@"%s--index---%ld",__func__,(long)buttonIndex);
    
};
- (void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex{ // after animation
    NSLog(@"%s--index---%ld",__func__,(long)buttonIndex);
    
}

// Called after edits in any of the default fields added by the style
- (BOOL)alertViewShouldEnableFirstOtherButton:(UIAlertView *)alertView{
    return YES;
}


//注意：
//1,如果想要自动的退出alertView而不是点击按钮推出，选择相面的方式：(需要设置定时器,定时器的使用可以在定时器章节查看)
[alertView dismissWithClickedButtonIndex:3 animated:YES];
/

三，UIActionSheet的使用：

1，创建actionSheet：//你可以在创建的时候决定上面有多少个按钮

UIActionSheet *actionSheet = [[UIActionSheet alloc] initWithTitle:@"ActionSheet" delegate:self cancelButtonTitle:@"cancel" destructiveButtonTitle:@"Sure?" otherButtonTitles:@"really?", nil];

//创建后如果想要增加按钮也可以：（按钮如果太多，会通过scroll方式展示）
[actionSheet addButtonWithTitle:@"jjjjjjj"];

2，设置UIAlertView样式：（共有四种样式）(不知道为什么我设置的时候好想没有什么作用，以后在研究)


//    UIActionSheetStyleAutomatic        = -1,       // take appearance from toolbar style otherwise uses 'default'
//    UIActionSheetStyleDefault          = UIBarStyleDefault,
//    UIActionSheetStyleBlackTranslucent = UIBarStyleBlackTranslucent,
//    UIActionSheetStyleBlackOpaque      = UIBarStyleBlackOpaque ,
actionSheet.actionSheetStyle = UIActionSheetStyleBlackOpaque;

3，若还未设置代理，请在这里设置代理，（由于在创建的时候我已经设置过了，这里就不再设置）展示出来

[actionSheet showInView:self.view];