How can i set the default selected value of a jcombobox which is inside a jtable?

Question!
model = new DefaultComboBoxModel<>();
    model.addElement("Absent");
    model.addElement("Present");
    model.addElement("On Leave");
    model.setSelectedItem("Absent");

    JComboBox cbox = new JComboBox(model);
    DefaultTableModel attModel = (DefaultTableModel)tableEmpAtt.getModel();
    TableColumn col = tableEmpAtt.getColumnModel().getColumn(3);
    col.setCellEditor(new DefaultCellEditor(cbox));

adding rows :

ResultSet rs = st.executeQuery("select Employee_ID,First_Name,Last_Name,Contact_No from Employee_Information");
        while(rs.next()){
            attModel.addRow(new Object[]{rs.getInt(1),rs.getString(2)+" "+rs.getString(3),rs.getString(4)});
        }

this is how it looks on load this is how it looks on load

this is how it looks when a cell under presence is clicked once this is how it looks when a cell under presence is clicked once

i want to set it so that when its loaded for the first time the column presence has a default value of absent



Answers

i want to set it so that when its loaded for the first time the column presence has a default value of absent

The combo box will only select the value that is in the TableModel.

So you need to add "Absent" to the table model when you add each row:

//attModel.addRow(new Object[]{rs.getInt(1),rs.getString(2)+" "+rs.getString(3),rs.getString(4)});

Vector<Object> row = new Vector<Object>();
row.addElement(rs.getInt(1));
row.addElement(rs.getString(2) + " " + rs.getString(3));
row.addElement(rs.getString(4));
row.addElement("Absent");
attModel.addRow( row );
By : camickr


You're first argument is the path to the executable. -> c://.../watcher.exe. The second is the directory to watch.

It's crashing when you print args[2] because there isn't a 3rd argument. If you wanted to add one in VS2015, you would click on the solution->properties->debug. You can set the command line arguments here under "Command line arguments." You should also be able to debug just by clicking on a line and adding breakpoints.

By : Ryan


I would do a little pre-processing before drawing the numbers to get a list of possible ranges. So let's assume we have a Range structure like so:

/// <summary> A possible range of values. </summary>
public struct Range
{
    /// <summary> Min value, inclusive. </summary>
    public readonly double Min;
    /// <summary> Max value, inclusive. </summary>
    public readonly double Max;
    public Range(double min, double max) { Min = min; Max = max; }
    /// <summary> Range length, distance between Min and Max. </summary>
    public double Length { get { return Max - Min; } }
}

And another structure RangeList which holds several ranges together. Range list also contains a cumulative length array of successive length sums of your Ranges, like so:

/// <summary> All possible ranges grouped together. </summary>
public struct RangeList
{
    /// <summary> Possible range. </summary>
    public readonly Range[] Ranges;
    /// <summary> Sum of each range length. </summary>
    public readonly double Length;
    /// <summary> Cumulative lengths values of each ranges. </summary>
    public readonly double[] CumulLengths;
    public RangeList(Range[] ranges)
    {
        Ranges = ranges;
        Length = 0;
        CumulLengths = new double[ranges.Length];
        for (var i = 0; i < ranges.Length; ++i)
        {
            Length += ranges[i].Length;
            CumulLengths[i] = Length;
        }
    }
}

We can then write easily a function that creates a RangeList from a given list of excluded ranges:

    /// <summary> Get possible ranges to draw from, considering exclusions. </summary>
    public static RangeList GetRangeList(Range range, params Range[] exclusions)
    {
        var ranges = new List<Range>();
        ranges.Add(range);
        if (exclusions != null)
        {
            foreach (var exclusion in exclusions)
            { // progressively eat latest range added to the list, cutting exclusions.
                var lastRange = ranges[ranges.Count - 1];
                if (exclusion.Min < lastRange.Max)
                {
                    ranges[ranges.Count - 1] = new Range(lastRange.Min, exclusion.Min);
                    if (exclusion.Max < lastRange.Max)
                    {
                        ranges.Add(new Range(exclusion.Max, lastRange.Max));
                    }
                }
            }
        }
        return new RangeList(ranges.ToArray());
    }

This method relies on several assumptions, including that not all space is excluded, exclusions are not overlapping, and exclusions are given in ascending order. It is then straight-forward to draw a number from the possible ranges:

    /// <summary> Assume exclusions are also given in ranges. </summary>
    public static double RangeWithExclusions(this Random random, Range range, params Range[] exclusions)
    {
        var rangeList = GetRangeList(range, exclusions);
        var rnd = random.NextDouble() * rangeList.Length;
        var rangeIndex = Array.BinarySearch(rangeList.CumulLengths, rnd);
        if (rangeIndex < 0)
        { // 'unlucky', we didn't hit a length exactly
            rangeIndex = ~rangeIndex;
        }
        var previousLength = rangeIndex > 0 ? rangeList.CumulLengths[rangeIndex - 1] : 0;
        var rndRange = rangeList.Ranges[rangeIndex]; // result range of our random draw
        return rndRange.Min + (rnd - previousLength); // scale rnd back into range space
    }

The following NUnit test demonstrate how to use the solution:

[TestFixture]
public class TestRandom
{
    [Test]
    public void Tests()
    {
        var random = new Random();
        double rnd;
        rnd = random.RangeWithExclusions(new Range(0, 1));
        Assert.IsTrue(rnd >= 0 && rnd <= 1);
        rnd = random.RangeWithExclusions(new Range(-100, 1));
        Assert.IsTrue(rnd >= -100 && rnd <= 1);
        rnd = random.RangeWithExclusions(new Range(0, 1), new Range(0.1, 0.9));
        Assert.IsTrue(rnd >= 0 && rnd <= 1 && (rnd <= 0.1 || rnd >= 0.9));
        rnd = random.RangeWithExclusions(new Range(0, 1), new Range(0, 0.9));
        Assert.IsTrue(rnd >= 0 && rnd <= 1 && (rnd >= 0.9));
        rnd = random.RangeWithExclusions(new Range(0, 1), new Range(0.2, 0.4), new Range(0.6, 0.8));
        Assert.IsTrue(rnd >= 0 && rnd <= 1 && (rnd <= 0.2 || rnd >= 0.4) && (rnd <= 0.6 || rnd >= 0.8));
    }
}

Hope this helps

By : pstrato


This video can help you solving your question :)
By: admin