Application built for API 8 does not work with API 7 - what goes wrong?

Hey guys I simply want to downgrade my api level 8 to 7 so that i can run the application both on 2.2 and 2.1 devices. The application is running perfectly fine on 2.2 and is having problem working on 2.1

I have done changes in manifest.xml and project -> properties

My application basically uses sax parser , facebook sdk , twitter connect

This is the log cat:

03-05 12:32:13.553: WARN/dalvikvm(232): threadid=3: thread exiting with uncaught exception (group=0x4001b188)
03-05 12:32:13.563: ERROR/AndroidRuntime(232): Uncaught handler: thread main exiting due to uncaught exception
03-05 12:32:13.623: ERROR/AndroidRuntime(232): java.lang.NullPointerException
03-05 12:32:13.623: ERROR/AndroidRuntime(232):     at com.test.activity.MyActivity$FetchTopMusic.onPostExecute(MusicScreen.java:161)
03-05 12:32:13.623: ERROR/AndroidRuntime(232):     at com.test.activity.MyActivity$FetchTopMusic.onPostExecute(MusicScreen.java:1)
03-05 12:32:13.623: ERROR/AndroidRuntime(232):     at android.os.AsyncTask.finish(AsyncTask.java:417)
03-05 12:32:13.623: ERROR/AndroidRuntime(232):     at android.os.AsyncTask.access$300(AsyncTask.java:127)
03-05 12:32:13.623: ERROR/AndroidRuntime(232):     at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:429)
03-05 12:32:13.623: ERROR/AndroidRuntime(232):     at android.os.Handler.dispatchMessage(Handler.java:99)
03-05 12:32:13.623: ERROR/AndroidRuntime(232):     at android.os.Looper.loop(Looper.java:123)
03-05 12:32:13.623: ERROR/AndroidRuntime(232):     at android.app.ActivityThread.main(ActivityThread.java:4363)
03-05 12:32:13.623: ERROR/AndroidRuntime(232):     at java.lang.reflect.Method.invokeNative(Native Method)
03-05 12:32:13.623: ERROR/AndroidRuntime(2开发者_开发问答32):     at java.lang.reflect.Method.invoke(Method.java:521)
03-05 12:32:13.623: ERROR/AndroidRuntime(232):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
03-05 12:32:13.623: ERROR/AndroidRuntime(232):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
03-05 12:32:13.623: ERROR/AndroidRuntime(232):     at dalvik.system.NativeStart.main(Native Method)

And i get this message after the splash screen. Music Screen has async task which is calling various classes in various packages for parsing the xml content. Is this a problem in xml parser??

The line 161 is :- for (int i = 0; i < tracks.size(); i++)

Where tracks is an arrayList and all this code is working fine in 2.2

Have you checked in the default properties and set the target to 7? Then check whether it is possible or not.

Let me know...