Updating JTable on button click

问题

I am working with a JTable with a Custom Table Model found here. I have updated my code with the suggestions provided in that post and have run into a new problem. The change I have made to my code was to inject an ArrayList<CompletedPlayer> into my JTable to avoid issues with threads. After doing that, the code to update my table by pressing a button has stopped working.

The code used to initialize the JTable is the following:

TableModel model = new PlayerTableModel(FileHandler.getCompletedPlayers());
JTable table = new JTable(model);

The code I used to update the JTable is the following:

JButton btnRefreshAllPlayers = new JButton("Refresh");

btnRefreshAllPlayers.addActionListener(new ActionListener() {

    public void actionPerformed(ActionEvent arg0) {

        PlayerTableModel model = (PlayerTableModel) table.getModel();
        model.fireTableDataChanged();

    }

});

I have also tried using repaint() but this does not work either. As of right now, the only way to get the JTable to update is to close and reopen the program. FileHandler has the ArrayList I am using for the JTable which increases in size as the user adds more players.

Why doesn't fireTableDataChanged() detect any changes?

回答1:

I have searched on stackoverflow and a couple of people have said to use that method.

No, you should not call any fireTableXxx methods outside of the context of the TableModel itself, people suggesting otherwise are simply wrong and it will cause you issues in the future. From the looks of your code, nothing has changed. If you've updated the TableModel according to the answer provided in your previous question, then there is no relationship with the data in the model to the external source. You need to manually reload the data from the external source, create a new TableModel and apply it to the table

For example...

JButton btnRefreshAllPlayers = new JButton("Refresh");

btnRefreshAllPlayers.addActionListener(new ActionListener() {

    public void actionPerformed(ActionEvent arg0) {

        TableModel model = new PlayerTableModel(FileHandler.getCompletedPlayers());
        table.setModel(model);

    }

});

I have also tried setting a new model with the updated ArrayList and it worked but did not keep the table row widths I previously set.

This is a reasonable thing for the table to do, because it has no idea if the new model has the same properties/columns as the old, so it resets them.

You could walk the ColumnModel, storing the column widths in a List or Map before you apply the model and reapply the widths

Is there a proper way to update the JTable?

You could provide your TableModel with a refresh method, which could load the data itself and trigger a tableDataChanged event

public class PlayerTableModel extends AbstractTableModel {
    private final List<PlayerSummary.Player> summaries;

    public PlayerTableModel(List<PlayerSummary.Player> summaries) {
        this.summaries = new ArrayList<PlayerSummary.Player>(summaries);
    }
    // Other TabelModel methods...

    public void refresh() {
        summaries = new ArrayList<>(FileHandler.getCompletedPlayers());
        fireTableDataChanged();
    }
}

Then you would need to call this method in your ActionListener...

PlayerTableModel model = (PlayerTableModel)table.getMode();
model.refresh();

来源：https://stackoverflow.com/questions/31527564/updating-jtable-on-button-click

标签

java

swing

jtable