iOS 的輸入框，是使用 UIAlertController。
一個簡單的對話框例子
您可以比較一下兩種不同的創建對話框的代碼，創建基礎UIAlertController的代碼和創建UIAlertView的代碼非常相似：
Objective-C版本：
UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"標題" message:@"這個是UIAlertController的默認樣式" preferredStyle:UIAlertControllerStyleAlert];
swift版本：
var alertController = UIAlertController(title: "標題", message: "這個是UIAlertController的默認樣式", preferredStyle: UIAlertControllerStyle.Alert)
同創建UIAlertView相比，我們無需指定代理，也無需在初始化過程中指定按鈕。不過要特別注意第三個參數，要確定您選擇的是對話框樣式還是上拉菜單樣式。
How to add text input in alertview of ios 8?
http://stackoverflow.com/questions/33996443/how-to-add-text-input-in-alertview-of-ios-8
UIAlertController * alertController = [UIAlertController alertControllerWithTitle: @"Login"
message: @"Input username and password"
preferredStyle:UIAlertControllerStyleAlert];
[alertController addTextFieldWithConfigurationHandler:^(UITextField *textField) {
textField.placeholder = @"name";
textField.textColor = [UIColor blueColor];
textField.clearButtonMode = UITextFieldViewModeWhileEditing;
textField.borderStyle = UITextBorderStyleRoundedRect;
}];
[alertController addTextFieldWithConfigurationHandler:^(UITextField *textField) {
textField.placeholder = @"password";
textField.textColor = [UIColor blueColor];
textField.clearButtonMode = UITextFieldViewModeWhileEditing;
textField.borderStyle = UITextBorderStyleRoundedRect;
textField.secureTextEntry = YES;
}];
[alertController addAction:[UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
NSArray * textfields = alertController.textFields;
UITextField * namefield = textfields[0];
UITextField * passwordfiled = textfields[1];
NSLog(@"%@:%@",namefield.text,passwordfiled.text);
}]];
[self presentViewController:alertController animated:YES completion:nil];
看要增加幾個選項按鈕都可以，而且都是用Block來做後續處理
範例：
UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"修改暱稱"
message:@""
preferredStyle:UIAlertControllerStyleAlert];
[alert addTextFieldWithConfigurationHandler:^(UITextField *textField) {
// optionally configure the text field
textField.keyboardType = UIKeyboardTypeDefault;
}];
UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"送出"
style:UIAlertActionStyleDefault
handler:^(UIAlertAction *action) {
UITextField *textField = [alert.textFields firstObject];
}];
[alert addAction:okAction];
UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {
}];
[alert addAction:cancelAction];
[self presentViewController:alert animated:YES completion:nil];
UIAlertController Example in iOS
http://hayageek.com/uialertcontroller-example-ios/
UIAlertController Changes in iOS 8
https://useyourloaf.com/blog/uialertcontroller-changes-in-ios-8/
Swift 範例：
https://www.simplifiedios.net/ios-dialog-box-with-input/
Apple 官方文件：
UIAlertController
https://developer.apple.com/reference/uikit/uialertcontroller