MIDP 2.0 version issues: $method is undefined for $type

问题

I've written a MIDlet that does several "advanced" things: fetching images from the web, resizing them, saving them on the phone, displaying them.

This all works perfectly in the Nokia S60 3rd Edition FP1 emulator. This device has MIDP 2.0 and CLDC 1.1 support (also JSR75, which I need in order to save files). It also works as it should on the Nokia E71 (physical device).

I then tried to run the MIDlet on several other emulators. One of them, the DefaultCldcJtwiPhone2 from the Java ME SDK 3.0, also claims MIDP 2.0 and CLDC 1.1 support. It doesn't have JSR75, which explains why "FileConnection can not be resolved to a type".

This does not, however, explain why List.deleteAll(), String.equalsIgnoreCase(String) and a few others are undefined.

The actual errors that I get:

• The method ceil(double) is undefined for the type Math
• The method deleteAll() is undefined for the type List
• The method equalsIgnoreCase(String) is undefined for the type String
• The method getWidth() is undefined for the type Displayable

When I look at the MIDP 2.0 (i.e. JSR118) API (http://java.sun.com/javame/reference/apis/jsr118/), I can clearly see all of these methods being present, with the "since" tag being either MIDP 2.0 or CLDC 1.1.

My question: why doesn't an emulator with MIDP 2.0 support have access to all MIDP 2.0 methods? Or alternatively, what am I doing wrong?

回答1:

Sounds like you're using methods defined in CLDC 1.1; the emulator you are using must only support CLDC 1.0 (this would certainly explain the lack of equalsIgnoreCase() and anything involving double and float primitives). See the full API here. And see here for a list of differences between 1.0 and 1.1.

EDIT: Some ways to check the CLDC version of your device:

1) Check the microedition.configuration system property as described here.

System.out.println("The CLDC version is:  " + System.getProperty("microedition.configuration"));

2) Check the existence of a class supported only in 1.1.

try {
    Class.forName("java.lang.ref.WeakReference");
    System.out.println("It's CLDC 1.1");
} catch (ClassNotFoundException e) {
    System.out.println("It's CLDC 1.0");
}

回答2:

Eclipse references both cldc_1.0.jar and cldc_1.1.jar (as well as midp_2.0.jar and midp_2.1.jar).

To fix it: Go to Window > Preferences > Java ME > Device Managment > your-device > Edit... > Libraries > cldc_1.0.jar > Remove

More details you can find here: http://thompsonng.blogspot.com/2009/09/j2me-setting-eclipse-to-use-cldc-11.html

回答3:

Even after you have chosen an emulator device that supports CLDC-1.1 , like DefaultCldcJtwiPhone2, you can still configure it to emulate a CLDC-1.0 only phone.

At least that's what the project properties on Netbeans look like.

回答4:

I got the same problem today(11/03/10) after updating from: SDK 1.6.0_17 + eclipse ee 3.5.1 + Java_ME_platform_SDK_3.0 EA. to: SDK 1.6.0_18 + eclipse ee 3.5.2 + Java_ME_platform_SDK_3.0.

The method ceil(double) is undefined for the type Math The method floor(double) is undefined for the type Math The method abs(int) in the type Math is not applicable for the arguments (double) The method sqrt(double) is undefined for the type Math

来源：https://stackoverflow.com/questions/2415778/midp-2-0-version-issues-method-is-undefined-for-type