Error: The method xxx is undefined for the type ActivityManager

Question

I am getting the following error:

ERROR: The method killBackgroundProcesses(String) is undefined for the type ActivityManager

Now I am dead sure that ActivityManager contains that method http://developer.android.com/reference/android/app/ActivityManager.html#killBackgroundProcesses%28java.lang.String%29.

Here is the code, please help me figure out where I am going wrong?

package com.robosoft.killswitch;

import java.util.List;

import android.app.ActivityManager;
import android.app.ListActivity;
import android.app.ActivityManager.RunningAppProcessInfo;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.AdapterView.OnItemClickListener;

public class KillSwitch extends ListActivity {
/** Called when the activity is first created. */
private RunningApplicationAdapter runningApplicationAdapter;
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    ActivityManager am = (ActivityManager)getSystemService(Context.ACTIVITY_SERVICE);
    final List<ActivityManager.RunningAppProcessInfo> RunningApp = am.getRunningAppProcesses();        
    runningApplicationAdapter = new RunningApplicationAdapter(this, RunningApp);
    //setContentView(R.layout.main);

    setListAdapter(runningApplicationAdapter);
    ListView lv = getListView();
    lv.setTextFilterEnabled(true);
    lv.setOnItemClickListener(new OnItemClickListener()
    {  
        public void onItemClick(AdapterView<?> parent, View v, int pos, long id) {
            RunningAppProcessInfo x = RunningApp.get(pos);
            String y = x.processName;
            am.killBackgroundProcesses(x.processName); //Error Here!
    }
    });
}
}

Answer 1

The only reason I see is the API level between the emulator (or device) you are using and the one you are using to develop could be different. i.e. You are using API level 8 to develop and deploying it on emulator AVD (or device) with API level lower than 8 (API 7 maybe)

The API level 7 did not have this method

Its only available in API level 8

Answer 2

This is your only solution.

private void initializeKillMethod() {
            try {
                    this.killMethod = ActivityManager.class.getMethod("killBackgroundProcesses", String.class);
            } catch (SecurityException e) {
                    e.printStackTrace();
            } catch (NoSuchMethodException e) {
                    e.printStackTrace();
            }

            if (this.killMethod != null) {
                    return;
            }

            try {
                    this.killMethod = ActivityManager.class.getMethod("restartPackage", String.class);
            } catch (SecurityException e) {
                    e.printStackTrace();
            } catch (NoSuchMethodException e) {
                    e.printStackTrace();
            }
    }

EDIT: For the record... I hate the code formatter here on StackOverflow because it sucks! Half of the time when you post code it kills all of the formatting.

Here is your solution with a button click listener. http://androidworkz.com/2010/07/26/backward-compatible-killbackgroundprocesses/