iOS iOS8新特性--UIAlertController

1. iOS7及iOS7之前警告类控件有UIAlertView和UIActionSheet

1.1 UIAlertView的使用

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"警告" message:@"这是一个UIAlertView" delegate:nil cancelButtonTitle:@"取消" otherButtonTitles:@"关闭", nil];

alert.alertViewStyle = UIAlertViewStylePlainTextInput;

/** alertViewStyle的枚举值如下

UIAlertViewStyleDefault = 0,

UIAlertViewStyleSecureTextInput,

UIAlertViewStylePlainTextInput,

UIAlertViewStyleLoginAndPasswordInput

*/

[alert show];

// UIAlertViewDelegate

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

1.2 UIActionSheet的使用

UIActionSheet *sheet = [[UIActionSheet alloc] initWithTitle:@"这是一个UIActionSheet" delegate:self cancelButtonTitle:@"取消" destructiveButtonTitle:@"确定"

otherButtonTitles:@"关闭", nil];

[sheet showInView:self.view];

// UIActionSheetDelegate

- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex

2. iOS8开始,用UIAlertController替代UIAlertView+UIActionSheet

2.1 UIAlertController的使用 (Style: UIAlertControllerStyleAlert)

// 初始化UIAlertController

　 UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"警告" message:@"iOS新控件UIAlertController" preferredStyle:UIAlertControllerStyleAlert];

// 添加按钮,注意如果Block的循环引用

__weak typeof(alert) weakAlert = alert;

[alert addAction:[UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDestructive handler:^(UIAlertAction *action) {

　　　　// block内部写点击按钮之后做的事情

　　　　NSLog(@"点击了确定按钮--%@-%@", [weakAlert.textFields.firstObject text], [weakAlert.textFields.lastObject text]);

}]];

// 添加文本框

[alert addTextFieldWithConfigurationHandler:^(UITextField *textField) {

textField.textColor = [UIColor blueColor];

textField.text = @"请输入用户名";

[textField addTarget:self action:@selector(usernameDidChange:) forControlEvents:UIControlEventEditingChanged];

// 也可以用通知监听TextField的变化

　　 //[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(usernameDidChange:) name:UITextFieldTextDidChangeNotification object:textField];

}];

[alert addTextFieldWithConfigurationHandler:^(UITextField *textField) {

textField.secureTextEntry = YES;

textField.text = @"123456";

}];

// 弹出UIAlertController

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

// textField EditingChanged时,回调的方法

- (void)usernameDidChange:(UITextField *)username

{

NSLog(@"%@", username.text);

}

2.2 UIAlertController的使用 (Style: UIAlertControllerStyleActionSheet)

// 在2.1代码上,修改 初始化UIAlertController 的代码

　 UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"警告" message:@"iOS新控件UIAlertController" preferredStyle:

UIAlertControllerStyleActionSheet];

运行程序后报错,因为text field只能用在Style:UIAlertControllerStyleAlert 的UIAlertController上,把添加textFiled的代码注销掉,再运行程序就正常了

reason: 'Text fields can only be added to an alert controller of style UIAlertControllerStyleAlert'

2.3通过上面的介绍,可以看出苹果有意把UIAlertView,UIActionSheet统一在一起,实际上,苹果还统一了iphone和ipad的UIAlertController的处理方式

2.3.1 新建项目时,Devices选择Universal,语言选OC(截图错误)



2.3.2 在Main.storyboard中拖导航控制器,让mainViewController成为导航控制器的rootViewController

2.3.3 代码示例

　 // 初始化UIAlertController

UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"警告" message:@"iOS新控件UIAlertController" preferredStyle:

UIAlertControllerStyleAlert];

// 设置popover指向的item

alert.popoverPresentationController.barButtonItem = self.navigationItem.leftBarButtonItem;

// 添加按钮

[alert addAction:[UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDestructive handler:^(UIAlertAction *action) {

NSLog(@"点击了确定按钮");

}]];

[alert addAction:[UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction *action) {

NSLog(@"点击了取消按钮");

}]];

// 弹出UIAlertController

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

注:左图是在iphone上运行效果,右图是在ipad上的运行效果,Style为UIAlertControllerStyleAlert时,显示样式一致





2.3.4 把2.3.3的初始化代码改成Style:UIAlertControllerStyleActionSheet

UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"警告" message:@"iOS新控件UIAlertController" preferredStyle:UIAlertControllerStyleActionSheet];

注:左图是iphone,右图是ipad,用一份代码实现了在iphone和ipad上不同的显示样式