Passing a variable problem.

[kaizen9001]

Hi guys. I'm having a bit of bother (once again) with passing a variable between 2 classes.
In my first class(called imageFrame), I have the following line of code:

myImagePanel.displayPicture(defaultLoadImage);

the method that this refers to in the second class(called ImagePanel) is as follows:

     public void displayPicture(Image  displayImage) {
        gBuffer.drawImage(displayImage, 0, 0, null);
        paintComponent(this.getGraphics());
    }

The idea is that, I'd like "defaultLoadImage" to be passed into "displayImage", but I can't work out how to go about doing it. I know this is going to be a really simple answer, so sorry for the stupid question, but any help would really be appreciated.

Thanks.

[DarrylBurke]

Never use getGraphics of a Component in client code. Learn how to correctly perform custom painting:
Lesson: Performing Custom Painting (The Java™ Tutorials > Creating a GUI With JFC/Swing)

db

[kaizen9001]

The code above is from a lab as part of a my coursework so I'm afraid it has to be used in order to appease my lecturers. Regardless of how useless or inefficient it is.

[dlorde]

The code above is from a lab as part of a my coursework so I'm afraid it has to be used in order to appease my lecturers. Regardless of how useless or inefficient it is.

:eek:

Perhaps you could point out that in reading up about it, you've discovered that the lab code is, er, misguided, and provide the reference to the tutorial that explains why...

[kaizen9001]

Agreed, It's completely stupid. The idea is that we're being taught to work with other peoples code etc. Any ideas what I have to do to pass this variable across? I'm sure it's just a variable declaration somewhere, but I have no idea where it goes or how to go about writing it...

[DarrylBurke]

To call that code misguided is like calling murder a misdemeanor. Using getGraphics() of a Component in client code is 99.999% of the time just plain wrong.

The remaining 0.001% applies to sophisticated programs that perform necessary checks on the returned Graphics value to decide whether to use it for rendering. Certainly not coursework.

db

[kaizen9001]

... Ok, I understand that it's not correct... Regardless, it's still what I have to do. Can anyone please help me pass this variable?

[JosAH]

... Ok, I understand that it's not correct... Regardless, it's still what I have to do. Can anyone please help me pass this variable?

Most likely not because even if all our code is correct that getGraphics() call is likely to return null and your program will throw a NullPointerException.

kind regards,

Jos

[kaizen9001]

Ok doke. Thanks for your time guys.

[Fubarable]

Phew !

[JosAH]

Phew !

And remember: it was me who got you all off the hook ;-)

kind regards,

Jos

[Fubarable]

And remember: it was me who got you all off the hook ;-)

Heck, I wasn't even an active participant but was getting frustrated just reading this thread!

Kind regards,

not Jos

[DarrylBurke]

It's even more exasperating that this crappy code has evidently been around for at least four years.
Java Programming: NullPointerException doing my head in - thatsjava.com

Their one member who responded was even worse than the questioners.

db