How to switch Display between different classes in Java ME

Question

I am developing a Java ME program. The different forms are located in separate classes. I tried to switch display between main MIDlet and a class and succeeded. How to do the same between two classes? I am just a beginner in Java ME.

Lucifer · Accepted Answer · 2012-07-19T04:54:56.213

4

I use following code for the same,

First display a static Display variable in Midlet
```
private static Display display;
```

Now initialize the dislplay variable in class Constructor

public MyMidlet() {
     display = Display.getDisplay(this);
}

Now declare a getDisplay() method in Midlet class

public static Display getDisplay () {
     return display;
}

Now you can use this getDisplay() method to get the current Display's object and then set any class's form

MyMidlet.getDisplay().setCurrent(form);

edited Jul 19 '12 at 04:54

answered Jul 19 '12 at 04:08

Lucifer

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I am getting a nullopinter exception. Can you please elaborate the getDisplay() method. – Sabin Jose Jul 19 '12 at 04:52
@SabinJose, sorry, it was mistake from my side, please check the updated answer. – Lucifer Jul 19 '12 at 04:55

Douglas Frari · Answer 2 · 2012-07-19T16:20:50.470

3

Simplification is:

  Display.getDisplay(this).setCurrent(screen);

Where screen is an instance of LCDUI (Form, Alert...) or intance of Canvas object. The this is an instance of the MIDlet

edited Jul 19 '12 at 16:20

answered Jul 19 '12 at 16:15

Douglas Frari

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How to switch Display between different classes in Java ME

2 Answers2