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Thread: Help with racecar applet?

  1. #26
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    Default Re: Help with racecar applet?

    If the user is not entering numbers in the textfields, initialize them with numbers:
    JTextField one = new JTextField("25", 3);

    at the same speed.
    Is that because their values are all being changed by the same amount: 1
    If you don't understand my answer, don't ignore it, ask a question.

  2. #27
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    Default Re: Help with racecar applet?

    Is there a way i could use my textfield text(for example: 25 is entered) to change the speeds for my pictures instead of making them all go the same speed? also a way to change the text into an int, because Integer.parseInt isnt working

  3. #28
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    Default Re: Help with racecar applet?

    Integer.parseInt isnt working
    Please explain what happens. Add some println() statements to the code that prints out the value of the String passed to the parseInt() method and to print out the value of the int returned by parseInt().

    If you want the positions of each picture to change by different amounts, add a different amount to their x,y location values.
    x++; // adds one to x
    x = x + 4; // adds four to x
    If you don't understand my answer, don't ignore it, ask a question.

  4. #29
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    Default Re: Help with racecar applet?

    this is the new error im getting:
    java.lang.NumberFormatException: null
            at java.lang.Integer.parseInt(Integer.java:417)
            at java.lang.Integer.parseInt(Integer.java:499)
            at superclass.init(superclass.java:72)
            at sun.applet.AppletPanel.run(AppletPanel.java:424)
            at java.lang.Thread.run(Thread.java:619)
    after adding this to get my x's and Timer to work right:
    //in init:
    one = new JTextField("",3);
    text1 = one.getText();
    Car1 = Integer.parseInt(text2);
     
    two = new JTextField("", 3);
    text2 = one.getText();
    Car2 = Integer.parseInt(text2);
     
    three = new JTextField("", 3);
    text3 = one.getText();
    Car3 = Integer.parseInt(text3);
     
    four = new JTextField("", 3);
    text4 = one.getText();
    Car4 = Integer.parseInt(text4);
     
    //what i have in ActionListener for timer:
     private class TimerHandler implements ActionListener
    {
     
    	public void actionPerformed(ActionEvent event)
     
    {
     
    	a++;
    	a=(Car1 + (a));
    	b++;
    	b=(Car2 + (b));
    	c++;
    	c=(Car3 + (c));
    	d++;
    	d=(Car4 + (d));
    	repaint();
     
     
     
    }
     
     
    }

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    Default Re: Help with racecar applet?

    java.lang.NumberFormatException: null
    at java.lang.Integer.parseInt(Integer.java:417)
    at java.lang.Integer.parseInt(Integer.java:499)
    at superclass.init(superclass.java:72)
    Why is the code passing a null value to the parseInt() method called on line 72?

    one = new JTextField("",3);
    text1 = one.getText();
    Car1 = Integer.parseInt(text2);  <<<<<<< note text2 here NOT text1
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  6. #31
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    Default Re: Help with racecar applet?

    that's what im wondering. the line 72 in my code is:
    [CODE]
    Car1 = Integer.parseInt(text1);

    [\CODE]
    it seems to not want to do anything with turning the text into an int.

  7. #32
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    Default Re: Help with racecar applet?

    Is the value of text1 null? How and where does text1 get assigned a value? How does it get a null value?
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  8. #33
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    Default Re: Help with racecar applet?

    i was trying to set the value of text1 up with the text of the JTextField, and was gonna use the text in an Integer.parseInt for the Car1. i never declared text1 as null or any of that.

  9. #34
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    Default Re: Help with racecar applet?

    Where does text1 get assigned a value? It will be null if no value is assigned to it. If it is null, then parseInt() will throw the exception. So you must change the code to make sure text1 gets a value.
    If you don't understand my answer, don't ignore it, ask a question.

  10. #35
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    Default Re: Help with racecar applet?

    would the:
    	String text1 = one.getText();
    	int Car1 = Integer.parseInt(text1);
    be assigning it a value? i was giving it the text of the JTextField. the problem i guess is that until the app is initialized, then no value can be assigned because the user hasn't put them in yet. is there a way i could make it to where the code would have to wait until AFTER i initialized, entered number into the textbox, and clicked the button to get it to read it right?

  11. #36
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    Default Re: Help with racecar applet?

    If you are getting the numbers BEFORE the user has entered them, that doesn't make sense.
    The program should show the GUI and wait for the user to enter the data and to tell the program that the data is ready and that it can now get the data from the input fields where the user entered it. One way for the user to tell the program that the data is ready is by having a button the user presses when the data is ready.
    If you don't understand my answer, don't ignore it, ask a question.

  12. #37
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    Default Re: Help with racecar applet?

    i moved the code that i had up there to the TimerHandler:
    //this is the code for my timer in the init:
    timer1 = new Timer(50, new TimerHandler());
     
    //this code is for my timer to work
    private class TimerHandler implements ActionListener
    {
     
    	public void actionPerformed(ActionEvent event)
     
    {
    	text1 = one.getText();
    	Car1 = Integer.parseInt(text1);
     
    	text2 = one.getText();
    	Car2 = Integer.parseInt(text2);
     
    	text3 = one.getText();
    	Car3 = Integer.parseInt(text3);
     
    	text4 = one.getText();
    	Car4 = Integer.parseInt(text4);
     
     
     
    	a++;
    	a=(Car1 + (a));
    	b++;
    	b=(Car2 + (b));
    	c++;
    	c=(Car3 + (c));
    	d++;
    	d=(Car4 + (d));
    	repaint();
     
     
     
    }
     
     
    }

  13. #38
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    Default Re: Help with racecar applet?

    How does the user tell the program that there is data now? The timer is going to get the data every 50ms even if the user is not ready.
    If you don't understand my answer, don't ignore it, ask a question.

  14. #39
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    Default Re: Help with racecar applet?

    the timer doesn't start until the button is clicked, right? and yes i dont get the null error or any other exception now, the only problems im having is:
    a) trying to get the images to start back at the beginning when the stop button is clicked and the the start button is clicked again, and
    b) trying to separate the image from traveling together because no matter the speed i put in for each text field, they all go the same speed as Car1.

  15. #40
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    Default Re: Help with racecar applet?

    they all go the same speed as Car1.
    Where do each of the cars get their speed from? Check the code.
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    Default Re: Help with racecar applet?

    i did, and i got it working now. but do you know how to add music files to a java applet? i have the code and everything working now, thanks to your assistance and some critical thinking, but i need to do both a music file and want to try out a double buffer

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