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
