如何推動 GridbagLayout 不將組件放置在 JPanel 的中心

Question

問題在於組件的居中布局，GridBagLayout 始終“位於”JPanel 的中心，所以我不在乎它將如何在內部布局組件，我的問題是這些組件將在面板上的何處開始布局。

我試過：

panel.setAlignmentX( JPanel.LEFT_ALIGNMENT );

但它沒有幫助。

任何的想法？

Answer 1

您需要添加至少一個將填充水平空間的組件。 如果你沒有這樣的組件，你可以試試這個：

GridBagConstraints noFill = new GridBagConstraints();
noFill.anchor = GridBagConstraints.WEST;
noFill.fill = GridBagConstraints.NONE;

GridBagConstraints horizontalFill = new GridBagConstraints();
horizontalFill.anchor = GridBagConstraints.WEST;
horizontalFill.fill = GridBagConstraints.HORIZONTAL;    

panel.add(new JLabel("Left Aligned"), noFill);
panel.add(Box.createHorizontalGlue(), horizontalFill);

Answer 2

除了設置anchor和fill字段外，您可能還需要設置weightx字段。 這有助於指定調整大小的行為。

報價：

除非您為 weightx 或 weighty 指定至少一個非零值，否則所有組件都會聚集在其容器的中心。 這是因為當權重為 0.0（默認值）時，GridBagLayout 在其單元格網格和容器邊緣之間放置任何額外空間。

以下將保持myComponent錨定到NORTHWEST角。 假設this是JPanel或類似的：

setLayout(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();

// Specify horizontal fill, with top-left corner anchoring
c.fill = GridBagConstraints.HORIZONTAL;
c.anchor = GridBagConstraints.NORTHWEST;

// Select x- and y-direction weight. Without a non-zero weight,
// the component will still be centered in the given direction.
c.weightx = 1;
c.weighty = 1;

// Add child component
add(myComponent, c);

要保持子組件左對齊但垂直居中，只需設置anchor = WEST並刪除weighty = 1; .

Answer 3

您只需使用此實用程序 jar painless-gridbag即可完成。 它還使您使用 GridBagLayout 的代碼更漂亮，如下所示

PainlessGridBag gbl = new PainlessGridBag(getContentPane(), false);

gbl.row().cell(lblFirstName).cell(txtFirstName).fillX()
        .cell(lblFamilyName).cell(txtFamilyName).fillX();
gbl.row().cell(lblAddress).cellXRemainder(txtAddress).fillX();

gbl.doneAndPushEverythingToTop();

Answer 4

如果要更改組件在GridBagLayout創建的單元格中的位置，請使用GridBagConstraints 中的參數錨點。

Answer 5

我和你有同樣的問題。 通過將該面板添加到另一個具有 BorderLayout 和 NORTH 約束的面板中來解決它。

翁德雷

Answer 6

您可以將主布局設置為 flowlayout 並將對齊設置為左對齊。 在這個面板（flowlayout）中，添加一個gridbaglayout面板。 這也適用於 netbeans

Answer 7

另一種解決方案是在最右側，最底部添加兩個虛擬面板（容器）。 然后你調整 weightx 和 weighty 來分配額外的空間。 如果您將 1 設置為虛擬，那么所有額外的空間都分配給這個虛擬。

這是在netbeans 中形成的示例。

package tutorial;

/**
 *
 * @author ttn
 */
public class GridBag1 extends javax.swing.JPanel {

    /**
     * Creates new form GridBag1
     */
    public GridBag1() {
        initComponents();
    }

    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {
        java.awt.GridBagConstraints gridBagConstraints;

        jLabel1 = new javax.swing.JLabel();
        jTextField1 = new javax.swing.JTextField();
        jPanel1 = new javax.swing.JPanel();
        jPanel2 = new javax.swing.JPanel();
        jLabel2 = new javax.swing.JLabel();
        jTextField2 = new javax.swing.JTextField();
        jScrollPane1 = new javax.swing.JScrollPane();
        jTextArea1 = new javax.swing.JTextArea();

        setLayout(new java.awt.GridBagLayout());

        jLabel1.setText("jLabel1");
        gridBagConstraints = new java.awt.GridBagConstraints();
        gridBagConstraints.gridx = 0;
        gridBagConstraints.gridy = 0;
        add(jLabel1, gridBagConstraints);

        jTextField1.setText("jTextField1");
        jTextField1.setMinimumSize(new java.awt.Dimension(59, 20));
        gridBagConstraints = new java.awt.GridBagConstraints();
        gridBagConstraints.gridx = 1;
        gridBagConstraints.gridy = 0;
        gridBagConstraints.fill = java.awt.GridBagConstraints.HORIZONTAL;
        gridBagConstraints.weightx = 0.3;
        add(jTextField1, gridBagConstraints);

        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 227, Short.MAX_VALUE)
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 104, Short.MAX_VALUE)
        );

        gridBagConstraints = new java.awt.GridBagConstraints();
        gridBagConstraints.gridx = 2;
        gridBagConstraints.gridy = 0;
        gridBagConstraints.gridheight = 3;
        gridBagConstraints.fill = java.awt.GridBagConstraints.BOTH;
        gridBagConstraints.weightx = 1.0;
        add(jPanel1, gridBagConstraints);

        javax.swing.GroupLayout jPanel2Layout = new javax.swing.GroupLayout(jPanel2);
        jPanel2.setLayout(jPanel2Layout);
        jPanel2Layout.setHorizontalGroup(
            jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 172, Short.MAX_VALUE)
        );
        jPanel2Layout.setVerticalGroup(
            jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 196, Short.MAX_VALUE)
        );

        gridBagConstraints = new java.awt.GridBagConstraints();
        gridBagConstraints.gridx = 0;
        gridBagConstraints.gridy = 3;
        gridBagConstraints.gridwidth = 2;
        gridBagConstraints.fill = java.awt.GridBagConstraints.BOTH;
        gridBagConstraints.weighty = 1.0;
        add(jPanel2, gridBagConstraints);

        jLabel2.setText("jLabel2");
        gridBagConstraints = new java.awt.GridBagConstraints();
        gridBagConstraints.gridx = 0;
        gridBagConstraints.gridy = 1;
        add(jLabel2, gridBagConstraints);

        jTextField2.setText("jTextField2");
        jTextField2.setMinimumSize(new java.awt.Dimension(59, 20));
        gridBagConstraints = new java.awt.GridBagConstraints();
        gridBagConstraints.gridx = 1;
        gridBagConstraints.gridy = 1;
        gridBagConstraints.fill = java.awt.GridBagConstraints.HORIZONTAL;
        gridBagConstraints.weightx = 0.3;
        add(jTextField2, gridBagConstraints);

        jScrollPane1.setMinimumSize(new java.awt.Dimension(104, 64));

        jTextArea1.setColumns(20);
        jTextArea1.setRows(5);
        jScrollPane1.setViewportView(jTextArea1);

        gridBagConstraints = new java.awt.GridBagConstraints();
        gridBagConstraints.gridx = 0;
        gridBagConstraints.gridy = 2;
        gridBagConstraints.gridwidth = 2;
        gridBagConstraints.anchor = java.awt.GridBagConstraints.FIRST_LINE_START;
        add(jScrollPane1, gridBagConstraints);
    }// </editor-fold>                        


    // Variables declaration - do not modify                     
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JPanel jPanel1;
    private javax.swing.JPanel jPanel2;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JTextArea jTextArea1;
    private javax.swing.JTextField jTextField1;
    private javax.swing.JTextField jTextField2;
    // End of variables declaration                   
}