Hello I'm a newbie here,
I want to add pictures in my JFrame. I used the Grouplayout and tried to load my Image with help of this JPanel-Class. But when I use ".addComponent(Image)" it gave me the following error:
Exception in thread "main" java.lang.IllegalArgumentException: Component must be non-null at javax.swing.GroupLayout$ComponentSpring.(Unknown Source) at javax.swing.GroupLayout$ComponentSpring.(Unknown Source) at javax.swing.GroupLayout$Group.addComponent(Unknown Source) at javax.swing.GroupLayout$ParallelGroup.addComponent(Unknown Source) at javax.swing.GroupLayout$ParallelGroup.addComponent(Unknown Source) at javax.swing.GroupLayout$Group.addComponent(Unknown Source) at javax.swing.GroupLayout$ParallelGroup.addComponent(Unknown Source) at infpp.OceanLife.OceanLifeGUI.initializeGUI(OceanLifeGUI.java:237) at infpp.OceanLife.OceanLifeGUI.(OceanLifeGUI.java:50) at infpp.OceanLife.OceanLifeController.start(OceanLifeController.java:39) at infpp.OceanLife.OceanLifeMain.main(OceanLifeMain.java:22)
MyCode:
private Images image;
GroupLayout.ParallelGroup drawHorizontal = drawLayout.createParallelGroup(Alignment.LEADING);
drawHorizontal.addComponent(image);
GroupLayout.ParallelGroup drawVertical = drawLayout.createParallelGroup(Alignment.LEADING);
drawVertical.addComponent(image);
Edit:
ImageClass
public class Image extends JPanel{
OceanInterface ocean;
/**
* All Images that display the ocean
*/
public static BufferedImage oceanImage,
fishImage1, fishImage2, fishImage3,
plantImage1,plantImage2, bubbleImage1,
bubbleImage2, bubbleImage3,
stoneImage1, stoneImage2, sharkImage;
public Image() {
try {
oceanImage = ImageIO.read(new File("media/ocean.png"));
} catch (IOException ex) {
// If there is an error:
final JOptionPane optionPane
= new JOptionPane();
JOptionPane.showMessageDialog(
optionPane,
"Fail.",
"ERROR",
JOptionPane.ERROR_MESSAGE);
System.exit(0);
}
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(oceanImage, 0, 0, null); // see javadoc for more info on the parameters
}
}
Whole Code of GUI:
package infpp.OceanLife;
import java.awt.Color;
import java.awt.Dimension;
import java.util.LinkedList;
import javax.swing.BorderFactory;
import javax.swing.GroupLayout;
import javax.swing.GroupLayout.Alignment;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
public class OceanLifeGUI extends JFrame{
/**
* Ocean the you want to control and get displayed
*/
public OceanInterface ocean;
private Image image;
/**
* OceanGraphic object which contains the oceans drawing
*/
private OceanLifeGraphic oceanGraphic;
/**
* Method to create a new GUI with a given Ocean
*
* @param oc - OceanInterface you want to control and get displayed
*/
public OceanLifeGUI(OceanInterface oc) {
// Set the ocean
this.ocean = oc;
// Initialize the objects of the GUI
initializeGUI();
}
private void initializeGUI(){
// Create new JFrame
JFrame OceanLife = new JFrame();
// Default exit
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
// Create Panels (layout, oceanDraw, oceanControl)
JPanel oceanLayout = new JPanel();
JPanel oceanDraw = new JPanel();
JPanel oceanControl = new JPanel();
// Layoutmanager
GroupLayout layout = new GroupLayout(oceanLayout);
GroupLayout drawLayout = new GroupLayout(oceanDraw);
GroupLayout controlLayout = new GroupLayout(oceanControl);
// Set Layout
oceanDraw.setLayout(drawLayout);
oceanControl.setLayout(controlLayout);
// Creates Buttons
JButton loadButton = new JButton("Load");
JButton saveButton = new JButton("Save");
JButton quitButton = new JButton(" Quit ");
JButton startButton = new JButton("Start");
JButton stepButton = new JButton("Step ");
JButton stopButton = new JButton("Stop ");
JButton addButton = new JButton("ADD");
addButton.setPreferredSize(new Dimension (200,20));
JButton deselectButton = new JButton("DESELECT");
JButton removeButton = new JButton("REMOVE");
JButton clearButton = new JButton("CLEAR");
// Create Labels
JLabel gameControlLabel = new JLabel("Gamecontrol");
JLabel objectControlLabel = new JLabel("Objectcontrol");
JLabel xLabel = new JLabel("x");
JLabel yLabel = new JLabel("y");
// Create Textfields
JTextField xInput = new JTextField("0");
JTextField yInput = new JTextField("0");
// Create ComboBox
JComboBox objectSelectBox = new JComboBox(new String[] { "Fish", "Plant", "Stone", "Bubble" });
// Create List
JList objectSelectList = new JList(new String[] { "Fish", "Plant", "Stone", "Bubble" });
JScrollPane objectSelectScroll = new JScrollPane(objectSelectList);
// Control Panel
GroupLayout.ParallelGroup controlHorizontal = controlLayout.createParallelGroup();
GroupLayout.ParallelGroup controlPanel = controlLayout.createParallelGroup(Alignment.CENTER);
// GamecontrolLabel (1)
// GamecontrolButtons (2)
GroupLayout.SequentialGroup gameControlButtons = controlLayout.createSequentialGroup();
GroupLayout.ParallelGroup columnLeft = controlLayout.createParallelGroup();
columnLeft.addComponent(loadButton);
columnLeft.addComponent(startButton);
GroupLayout.ParallelGroup columnMiddle = controlLayout.createParallelGroup();
columnMiddle.addComponent(saveButton);
columnMiddle.addComponent(stepButton);
GroupLayout.ParallelGroup columnRight = controlLayout.createParallelGroup();
columnRight.addComponent(quitButton);
columnRight.addComponent(stopButton);
gameControlButtons.addGroup(columnLeft);
gameControlButtons.addGap(5,5,5);
gameControlButtons.addGroup(columnMiddle);
gameControlButtons.addGap(5,5,5);
gameControlButtons.addGroup(columnRight);
// ObjectcontrolLabel (3)
// ObjectSelect and ADD (4)
GroupLayout.SequentialGroup objectSelect = controlLayout.createSequentialGroup();
objectSelect.addComponent(objectSelectBox);
objectSelect.addGap(5,5,5);
objectSelect.addComponent(xLabel);
objectSelect.addGap(5,5,5);
objectSelect.addComponent(xInput);
objectSelect.addGap(5,5,5);
objectSelect.addComponent(yLabel);
objectSelect.addGap(5,5,5);
objectSelect.addComponent(yInput);
// ADD-Button (5)
// ObjectSelectList with ScrollPanel (6)
// DESELECT-Button (7)
// REMOVE-Button (8)
// CLEAR-Button (9)
// Call controlPanel-Components
controlPanel.addComponent(gameControlLabel);
controlPanel.addGroup(gameControlButtons);
controlPanel.addComponent(objectControlLabel);
controlPanel.addGroup(objectSelect);
controlPanel.addComponent(addButton);
controlPanel.addComponent(objectSelectScroll);
controlPanel.addComponent(deselectButton);
controlPanel.addComponent(removeButton);
controlPanel.addComponent(clearButton);
// Call Horizontal-Groups
controlHorizontal.addGroup(controlPanel);
GroupLayout.SequentialGroup controlVertical = controlLayout.createSequentialGroup();
GroupLayout.ParallelGroup firstRow = controlLayout.createParallelGroup();
firstRow.addComponent(loadButton);
firstRow.addComponent(saveButton);
firstRow.addComponent(quitButton);
GroupLayout.ParallelGroup secondRow = controlLayout.createParallelGroup();
secondRow.addComponent(startButton);
secondRow.addComponent(stepButton);
secondRow.addComponent(stopButton);
GroupLayout.ParallelGroup thirdRow = controlLayout.createParallelGroup(Alignment.BASELINE);
thirdRow.addComponent(objectSelectBox);
thirdRow.addComponent(xLabel);
thirdRow.addComponent(xInput);
thirdRow.addComponent(yLabel);
thirdRow.addComponent(yInput);
GroupLayout.ParallelGroup fourthRow = controlLayout.createParallelGroup(Alignment.BASELINE);
fourthRow.addComponent(addButton, 200,200,200);
// Call Vertical-Groups
controlVertical.addComponent(gameControlLabel);
controlVertical.addGap(5,5,5);
controlVertical.addGroup(firstRow);
controlVertical.addGap(5,5,5);
controlVertical.addGroup(secondRow);
controlVertical.addGap(200,200,200);
controlVertical.addComponent(objectControlLabel);
controlVertical.addGap(5,5,5);
controlVertical.addGroup(thirdRow);
controlVertical.addGap(5,5,5);
controlVertical.addComponent(addButton);
controlVertical.addGap(5,5,5);
controlVertical.addComponent(objectSelectScroll);
controlVertical.addGap(5,5,5);
controlVertical.addComponent(deselectButton);
controlVertical.addGap(5,5,5);
controlVertical.addComponent(removeButton);
controlVertical.addGap(5,5,5);
controlVertical.addComponent(clearButton);
controlVertical.addGap(5,5,5);
// OceanDraw
GroupLayout.ParallelGroup drawHorizontal = drawLayout.createParallelGroup(Alignment.LEADING);
drawHorizontal.addComponent(image);
GroupLayout.ParallelGroup drawVertical = drawLayout.createParallelGroup(Alignment.LEADING);
drawVertical.addComponent(image);
// Layout
GroupLayout.ParallelGroup layoutHorizontal = layout.createParallelGroup();
layoutHorizontal.addComponent(oceanDraw);
layoutHorizontal.addComponent(oceanControl);
GroupLayout.SequentialGroup layoutVertical = layout.createSequentialGroup();
layoutVertical.addComponent(oceanControl);
layoutVertical.addComponent(oceanDraw);
controlLayout.setHorizontalGroup(controlHorizontal);
controlLayout.setVerticalGroup(controlVertical);
drawLayout.setHorizontalGroup(drawHorizontal);
drawLayout.setVerticalGroup(drawVertical);
layout.setHorizontalGroup(layoutHorizontal);
layout.setVerticalGroup(layoutVertical);
// Add Panels (OceanDraw, OceanControl) to jFrame (OceanLife)
OceanLife.add(oceanLayout);
//OceanLife.add(oceanDraw);
oceanDraw.setBackground(Color.black);
oceanDraw.setPreferredSize(new Dimension (1000,600));
// Pack?
OceanLife.pack();
OceanLife.setVisible(true);
OceanLife.setResizable(false);
OceanLife.setSize(1220, 650);
}
}
Your problem is that you have declared the variable image but did not initialise it. So the variable is null when you are using the variable image in drawHorizontal.addComponent(image);.
So, my suggestion is that you initialise the variable image like :
image = new Image();
before the line drawHorizontal.addComponent(image);