建立及使用UIAlertController

一。UIAlertControllerStyleActionSheet底部

typedef NS_ENUM(NSInteger, UIAlertControllerStyle) {

UIAlertControllerStyleActionSheet = 0,底部

UIAlertControllerStyleAlert 中间

}

UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"自定义背景" message:nil preferredStyle:UIAlertControllerStyleActionSheet];//建立对象
	[self presentViewController:alertController animated:YES completion:nil];//展现alertController，相似于拍照的UIImagePickerController，是一个试图控制器。
	UIAlertAction *cancleAction = [UIAlertAction actionWithTitle:@"取消cancel" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {
		NSLog(@"cancel");//点击按钮触发的事件在这里写
	}];//建立按钮
UIAlertAction *defaultAction = [UIAlertAction actionWithTitle:@"默认default" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
		NSLog(@"默认default");
	}];
	UIAlertAction *defaultAction1 = [UIAlertAction actionWithTitle:@"默认default1" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
		NSLog(@"默认default1");
	}];
	UIAlertAction *resetAction = [UIAlertAction actionWithTitle:@"重置reset" style:UIAlertActionStyleDestructive handler:^(UIAlertAction * _Nonnull action) {
		NSLog(@"reset");
	}];
	UIAlertAction *resetAction1 = [UIAlertAction actionWithTitle:@"重置reset1" style:UIAlertActionStyleDestructive handler:^(UIAlertAction * _Nonnull action) {
		NSLog(@"reset1");
	}];
	[alertController addAction:cancleAction];//添加按钮
	[alertController addAction:defaultAction1];
	[alertController addAction:defaultAction];
	[alertController addAction:resetAction];
	[alertController addAction:resetAction1];

注：在苹果上，Cancel按钮在左边/最底部，其余的按添加顺序显示。

UIAlertActionStyle有三种：UIAlertActionStyleDefault = 0, UIAlertActionStyleCancel,和UIAlertActionStyleDestructive，除了style为cancel只能够addiction一次，其余的能够添加多个按钮。

二。添加文本输入框：UIAlertControllerStyleAlert，中间

一、文本输入框只能添加到Alert的风格中，ActionSheet是不容许的；

二、UIAlertController具备只读属性的textFields数组，须要可直接按本身须要的顺序添加；

三、添加方式是使用block，参数是UITextField；

四、添加UITextField监听方法和实现方法。

UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"自定义背景" message:nil preferredStyle:UIAlertControllerStyleAlert];//建立对象
UIAlertAction *cancleAction = [UIAlertAction actionWithTitle:@"取消cancel" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {
		NSLog(@"cancel");//点击按钮触发的事件在这里写
	}];//建立按钮
	[alertController addAction:cancleAction];//添加上去

	[alertController addTextFieldWithConfigurationHandler:^(UITextField * _Nonnull textField) {
		textField.placeholder = @"111111";
	}];//添加输入框
	[alertController addTextFieldWithConfigurationHandler:^(UITextField * _Nonnull textField) {
		textField.placeholder = @"34444";
		[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textfieldDidChanged:) name:UITextFieldTextDidChangeNotification object:textField];//添加UITextFieldTextDidChangeNotification通知，一旦输入框text改变，在textfieldDidChanged：方法里可检测到输入状况
	}];
	[alertController addTextFieldWithConfigurationHandler:^(UITextField * _Nonnull textField) {
		textField.placeholder = @"jianting";
		[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textfieldDidChanged:) name:UITextFieldTextDidChangeNotification object:textField];
	}];

	UIAlertAction *getAction = [UIAlertAction actionWithTitle:@"默认default" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
		UITextField *login = alertController.textFields[0];
		UITextField *password = alertController.textFields[1];
		UITextField *three = alertController.textFields[2];
		[self.view endEditing:YES];
		NSLog(@"登录：%@, 密码：%@,three : %@", login.text, password.text,three.text );
	}];//获取输入框中的内容
	
	[alertController addAction:getAction];//添加按钮，点击时触发上面handle的操做。
	
	[self presentViewController:alertController animated:YES completion:nil];//展现视图控制器，这个必须写在后面，写在添加textfield以前显示不出输入框的。

- (void)textfieldDidChanged:(NSNotification *)noti {

NSLog(@"\n\n\n%s, noti = %@", __func__, noti);

}

这个是监听方法示例。

三。一个自定义标题颜色文字的实现。

UIAlertController *alertVC = [UIAlertController alertControllerWithTitle:@"Dont care what goes here, since we're about to change below" message:@"" preferredStyle:UIAlertControllerStyleActionSheet];
	NSMutableAttributedString *hogan = [[NSMutableAttributedString alloc] initWithString:@"Presenting the great... Hulk Hogan!"];
	[hogan addAttribute:NSFontAttributeName
				  value:[UIFont systemFontOfSize:50.0]
				  range:NSMakeRange(24, 11)];
	[alertVC setValue:hogan forKey:@"attributedTitle"];
	
	
	
	UIAlertAction *button = [UIAlertAction actionWithTitle:@"Label text"
													 style:UIAlertActionStyleDefault
												   handler:^(UIAlertAction *action){
													   //add code to make something happen once tapped
												   }];
//	UIImage *accessoryImage = [UIImage imageNamed:@"someImage"];
//	[button setValue:accessoryImage forKey:@"image"];
	[alertVC addAction:button];
	[self presentViewController:alertVC animated:YES completion:nil];