Question

我有一个警报视图，显示用户必须输入的文本字段作为必填项。问题是如果用户点击＆＃34;授权＆＃34;没有进入它，alertview被解雇。我无法找到一种方法，向用户显示它是强制性的，而不会忽略警报视图。

代码：

func tableView（tableView：UITableView！，didSelectRowAtIndexPath indexPath：NSIndexPath！） {

    print("You selected cell #\(self.empNameArr[indexPath.row])!")
    let alertController = UIAlertController(title: "OD Authorise", message: "", preferredStyle: UIAlertControllerStyle.Alert)

    let AUTHORISE = UIAlertAction(title: "AUTHORISE", style: UIAlertActionStyle.Default, handler: {
        alert -> Void in

        let firstTextField = alertController.textFields![3] as UITextField
        print("<><><><><><>",firstTextField.text)

    })

    let DENY = UIAlertAction(title: "DENY", style: UIAlertActionStyle.Default, handler: {
        (action : UIAlertAction!) -> Void in

    })

    let CANCEL = UIAlertAction(title: "CANCEL", style: UIAlertActionStyle.Default, handler: {
        (action : UIAlertAction!) -> Void in

    })


    alertController.addTextFieldWithConfigurationHandler { (txtRemarks : UITextField!) -> Void in
        txtRemarks.font = UIFont(name: (txtRemarks.font?.fontName)!, size: 11)
        txtRemarks.text = " Employee Name :\(self.empNameArr[indexPath.row]) "
        txtRemarks.userInteractionEnabled=false
        txtRemarks.borderStyle = UITextBorderStyle.None

    }

    alertController.addTextFieldWithConfigurationHandler { (txtRemarks : UITextField!) -> Void in
        txtRemarks.font = UIFont(name: (txtRemarks.font?.fontName)!, size: 11)
        txtRemarks.text = " From Date :\(self.leavDateArr[indexPath.row]) "
        txtRemarks.userInteractionEnabled=false
        txtRemarks.borderStyle = UITextBorderStyle.None

    }
    alertController.addTextFieldWithConfigurationHandler { (txtRemarks : UITextField!) -> Void in
        txtRemarks.font = UIFont(name: (txtRemarks.font?.fontName)!, size: 11)
        txtRemarks.text = " To Date :\(self.ToDate[indexPath.row]) "
        txtRemarks.userInteractionEnabled=false
        txtRemarks.borderStyle = UITextBorderStyle.None

    }



    alertController.addTextFieldWithConfigurationHandler { (txtRemarks : UITextField!) -> Void in
        txtRemarks.font = UIFont(name: (txtRemarks.font?.fontName)!, size: 11)
        txtRemarks.text = " Leave reason :\(self.Reason[indexPath.row]) "
        txtRemarks.userInteractionEnabled=false
        txtRemarks.borderStyle = UITextBorderStyle.None

    }


    alertController.addTextFieldWithConfigurationHandler { (txtRemarks : UITextField!) -> Void in
        txtRemarks.placeholder = "Enter Your Remarks"
        txtRemarks.font = UIFont(name: (txtRemarks.font?.fontName)!, size: 15)
        txtRemarks.userInteractionEnabled=true
        txtRemarks.borderStyle = UITextBorderStyle.Line
        txtRemarks.textAlignment = NSTextAlignment.Center

    }


    alertController.addAction(AUTHORISE)
    alertController.addAction(DENY)
    alertController.addAction(CANCEL)

    self.presentViewController(alertController, animated: true, completion: nil)

}

Answer 1

将您的班级设置为UIAlertViewDelegate，并将您的alrtView委托设置为您的班级。

然后这样做

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {
if (buttonIndex == 1) {
    NSString *name = [alertView textFieldAtIndex:0].text;
    // Here check for validation. If the text is empty disable button or however you would like to handle it
}
}

Answer 2

    class ViewController: UIViewController,UITextFieldDelegate
    {

        override func viewDidLoad() {
            super.viewDidLoad()
            // Do any additional setup after loading the view, typically from a nib.
        }

        override func didReceiveMemoryWarning() {
            super.didReceiveMemoryWarning()
            // Dispose of any resources that can be recreated.
        }

        var authorizeaction:UIAlertAction?

        @IBAction func tapBtnaction(sender: AnyObject)
        {
            let titleStr = "title"
            let messageStr = "message"

            let alert = UIAlertController(title: titleStr, message: messageStr, preferredStyle: UIAlertControllerStyle.Alert)

            let placeholderStr =  "Enter your Remarks"

            alert.addTextFieldWithConfigurationHandler({(textField: UITextField) in
                textField.placeholder = placeholderStr
                textField.addTarget(self, action: #selector(self.textChanged(_:)), forControlEvents: .EditingChanged)
            })

            let authorize = UIAlertAction(title: "Authorize", style: UIAlertActionStyle.Default, handler: { (_) -> Void in

            })

            let deny = UIAlertAction(title: "Deny", style: UIAlertActionStyle.Default, handler: { (_) -> Void in
                let textfield = alert.textFields!.first!

                //Do what you want with the textfield!
            })
            let cancel = UIAlertAction(title: "Cancel", style: UIAlertActionStyle.Cancel, handler: { (_) -> Void in
                let textfield = alert.textFields!.first!

                //Do what you want with the textfield!
            })
            alert.addAction(cancel)
            alert.addAction(authorize)
            alert.addAction(deny)

            //self.actionToEnable = action
            authorizeaction = authorize
            authorizeaction!.enabled = false
            self.presentViewController(alert, animated: true, completion: nil)


        }
        func textChanged(sender:UITextField)
        {

           if sender.text?.characters.count > 0
        {
        authorizeaction?.enabled = true
        }
        else
        {
            authorizeaction?.enabled = false
        }

        }

    }
Output:

修改

如果您不想启用或停用授权操作，则可以使用以下代码。

let authorize = UIAlertAction(title: "Authorize", style: UIAlertActionStyle.Default, handler: { (_) -> Void in if let textfield : UITextField = alert.textFields![0] { if textfield.text?.characters.count == 0 { //empty self.presentViewController(alert, animated: true, completion: { let tempAlert = UIAlertController(title: "Error", message: "Please Enter remarks", preferredStyle: UIAlertControllerStyle.Alert) tempAlert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.Cancel, handler: { (action) in })) alert.presentViewController(tempAlert, animated: true, completion: nil) }) } else { //authorize } } })

仅显示消息的替代选项是Toast。 https://github.com/scalessec/Toast

Answer 3

您需要将手势识别器添加到在解雇之前触发的UIAlertController 为此，您可以参考以下答案： Prevent UIAlertController to dismiss

否则，您可以使用以下代码：

import ilog.concert.*;
import ilog.cplex.*;
import java.util.*;

public class SimpleLP {

    public static void main(String[] args) {
        Solve();
    }
    public static void Solve() {
        int n = 4;
        int m = 3;

        double[] p = { 310.0, 380.0, 350.0, 285.0 };
        double[] v = { 480.0, 650.0, 580.0, 390.0 };
        double[] a = { 18.0, 15.0, 23.0, 12.0 }; 
        double[] c = { 10.0, 16.0, 8.0 }; 
        double[] V = { 6800.0, 8700.0, 5300.0 }; 

        try {

            IloCplex model = new IloCplex();

            IloNumVar[][] x = new IloNumVar[n][];
            for (int i = 0; i < n; i++) {
                x[i] = model.numVarArray(m, 0, Double.MAX_VALUE);
            }

            IloNumVar y = model.numVar(0, Double.MAX_VALUE);

            IloLinearNumExpr obj = model.linearNumExpr();
            for (int i = 0; i < n; i++) {
                for (int j = 0; j < m; j++) {
                    obj.addTerm(p[i], x[i][j]);
                }
            }

            model.addMaximize(obj);

            for (int i = 0; i < n; i++) {
                model.addLe(model.sum(x[i]), a[i]);
            }


            List<IloRange> Constraints = new ArrayList<IloRange>();

            IloLinearNumExpr [] usedWeightCap = new IloLinearNumExpr[m];
            IloLinearNumExpr [] usedVolumeCap = new IloLinearNumExpr[m];
            IloLinearNumExpr [] proportionalWeight = new IloLinearNumExpr[m];

            for (int j = 0; j < m; j++) {
                usedWeightCap[j] = model.linearNumExpr();
                usedVolumeCap[j] = model.linearNumExpr();
                proportionalWeight[j] = model.linearNumExpr();

                for (int i = 0; i < n; i++) {
                    usedWeightCap[j].addTerm(1.0, x[i][j]);
                    usedVolumeCap[j].addTerm(v[i], x[i][j]);
                    proportionalWeight[j].addTerm(1/c[j], x[i][j]);
                }
            }
            for (int j = 0; j < m; j++) {

                Constraints.add(model.addLe(usedWeightCap[j], c[j]));

                Constraints.add(model.addLe(usedVolumeCap[j], V[j]));

                //model.addEq(model.prod(1/c[j], usedWeightCap[j]), y);
                //Constraints.add(model.addEq(proportionalWeight[j], y)); /*This is my problem that I cannot add this constraint into the list*/
                model.addEq(proportionalWeight[j], y);
            }
            if (model.solve()) {
                System.out.println("Objective Value: "+ model.getObjValue());
                for (int i = 0; i < n; i++) {
                    for (int j = 0; j < m; j++) {
                        System.out.println("x*["+(i+1)+"]"+"["+(j+1)+"] : "+model.getValue(x[i][j]));
                    }
                }
                System.out.println("y* : "+ model.getValue(y));
            } else {
                System.out.println("Problem not solved :(");
            }

            model.end();

        } catch (IloException ex) {
            ex.printStackTrace();
        }
    }
}

有没有办法在使用swift的alertview内部的文本字段中提供验证

3 个答案: