Creating a header file for android activity class

Question

I have added few native methods to my android Activity class.Now I want to create the header file for that class.

I get the following error while creating the header file from command line.

C:\AndroidProjects\JniTest\bin\classes>javah -classpath .;
C:\adt-bundle-windows-x86\sdk\platforms\android.jar com.example.jnitest.JniTest
Error: cannot access android.app.Activity
class file for android.app.Activity not found

Basically unable to access the activity class form the jar.

Please advice.

Answer 1

Try the following in Eclipse,

Go to > Run | External Tools| External Tool Configurations Under Program create new configuration by clicking small icon.

Name it.

Location would be : C:\Program Files\Java\jdk1.7.0_04\bin\javah.exe

Working Directory would be: ${workspace_loc:/My_First_NDK/bin/classes} and

Arguments would be: -classpath ${workspace_loc:/My_First_NDK/bin/classes} -bootclasspath "C:\adt-bundle-windows-x86-20140624\sdk\platforms\android-19\android.jar" -v -d ${workspace_loc:/My_First_NDK/jni} com.mypackage.ndk.HelloNDK

Answer 2

The command would be (use backslashes (\), instead of forward slashes (/) while using Windows cmd):

javah -bootclasspath $ANDROID_SDK_ROOT/platforms/android-17/android.jar -classpath bin/classes com.example.jnitest.JniTest

You should use -bootclasspath instead of -classpath, since android.jar re-implements Java Class Library.

Assumptions:

• Your current directory is: C:\AndroidProjects\JniTest;
• Your Android SDK is installed in $ANDROID_SDK_ROOT (%ANDROID_SDK_ROOT% for Windows);
• Your target API Level is android-17.

Please modify your command accordingly.