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POTrying to print Array
 

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  1. POTrying to print Array
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    <p>I am currently trying to take user input from a textArea, place it into an array and then output the array in a textField. I am running into a nullPointerExeception currently. I am guessing it is because I am not gathering the input from the textArea correctly and placing it into the array. Please help. Eventually I am going to have to sort it out with Bubble, Merge, and Quick sort but I just want to make sure that I am taking the input and placing it into the array correctly. Please do NOT give me the answer on the sorting. Thank you.</p> <p>Currently the area that I am working with is within the Bubble Sort JButton.</p> <pre><code>import java.awt.EventQueue; import javax.swing.*; import java.awt.event.*; import java.util.*; public class Sorting { private JFrame frame; private JTextArea inputArea; private JTextField outputArea; List&lt;String&gt; list = new ArrayList&lt;String&gt;(); Scanner input = new Scanner(System.in); int array[]; int inputNumber = 0; /** * Launch the application. */ public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { public void run() { try { Sorting window = new Sorting(); window.frame.setVisible(true); } catch (Exception e) { e.printStackTrace(); } } }); } /** * Create the application. */ public Sorting() { initialize(); } /** * Initialize the contents of the frame. */ private void initialize() { frame = new JFrame(); frame.setBounds(100, 100, 450, 300); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setTitle("Sorting"); frame.getContentPane().setLayout(null); JButton bubbleButton = new JButton("Bubble Sort"); bubbleButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent arg0) { inputArea.getText(); array[inputNumber] = input.nextInt(); printArray(array); } private void printArray(int[] array) { int n = inputNumber; for(int i = 0; i &lt; n; i++){ outputArea.setText(array[i] + " "); } } }); bubbleButton.setBounds(10, 211, 114, 23); frame.getContentPane().add(bubbleButton); JButton mergeButton = new JButton("Merge Sort"); mergeButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { } }); mergeButton.setBounds(305, 211, 114, 23); frame.getContentPane().add(mergeButton); JButton quickButton = new JButton("Quick Sort"); quickButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { } }); quickButton.setBounds(163, 211, 114, 23); frame.getContentPane().add(quickButton); inputArea = new JTextArea(); inputArea.setBounds(10, 36, 414, 51); frame.getContentPane().add(inputArea); outputArea = new JTextField(); outputArea.setEditable(false); outputArea.setBounds(10, 98, 414, 59); frame.getContentPane().add(outputArea); outputArea.setColumns(10); JLabel label = new JLabel("Please Enter 5 Numbers"); label.setHorizontalAlignment(SwingConstants.CENTER); label.setBounds(10, 11, 414, 14); frame.getContentPane().add(label); } } </code></pre> <p>Currently when I run this program and press the Bubble Sort button it freezes and doesn't do anything.</p> <p>So I added this into the Bubble Sort button area to which I have changed.</p> <pre><code> JButton bubbleButton = new JButton("Bubble Sort"); bubbleButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent arg0) { ArrayList&lt;Integer&gt; list = new ArrayList&lt;Integer&gt;(); while (input.hasNext()) { list.add(input.nextInt()); } for (int i = 0; i &lt; 5; i++) { outputArea.setText(list.toString()); } } }); </code></pre> <p>It is still currently freezing but I am unsure as to why it would be freezing. Is there something I need to do to getText from inputArea??</p>
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    1. This table or related slice is empty.
    1. PTQuestion
    1. USuser2929005
    1. USuser2929005
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
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    1. PO
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    1. This table or related slice is empty.
    1. COyou never initialize your array, or do you?
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      1. POTrying to print Array
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    2. COThe stack trace of the exception tells you at which line it happens, which should tell you which variable is null.
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      1. USJB Nizet
    3. COSo I am guessing that I am not even adding the input into the array? for(int i = 0; i < array.length; i++){ array[i] = input.nextInt(); } In the for loop when it tries to run that line with array.length is when it throws the exception.
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