StateFragment.java

package org.commcare.android.framework;

import org.commcare.android.tasks.templates.CommCareTask;

import android.app.Activity;
import android.content.Context;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.PowerManager;
import android.os.PowerManager.WakeLock;
import android.support.v4.app.Fragment;
import android.util.Log;
/**
 * @author ctsims
 *
 */
public class StateFragment extends Fragment {
    
    CommCareActivity boundActivity;
    CommCareActivity lastActivity;
    
    CommCareTask currentTask;
    /*
     * (non-Javadoc)
     * @see android.support.v4.app.Fragment#onAttach(android.app.Activity)
     * 
     * Hold a reference to the parent Activity so we can report the
     * task's current progress and results. The Android framework 
     * will pass us a reference to the newly created Activity after 
     * each configuration change.
     */
      @Override
      public void onAttach(Activity activity) {
        super.onAttach(activity);
        if(activity instanceof CommCareActivity) {
            this.boundActivity = (CommCareActivity)activity;
            this.boundActivity.stateHolder = this;
            if(this.currentTask != null && this.currentTask.getStatus() == AsyncTask.Status.RUNNING) {
                this.currentTask.connect(boundActivity);
            }
        }
      }
      
      public CommCareActivity getPreviousState() { 
          return lastActivity;
      }
      
      public void connectTask(CommCareTask task) {
          this.currentTask = task;
      }
     
      /*
       * (non-Javadoc)
       * @see android.support.v4.app.Fragment#onCreate(android.os.Bundle)
       * 
       * This method will only be called once when the retained
       * Fragment is first created.
       */
      @Override
      public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
     
        // Retain this fragment across configuration changes.
        setRetainInstance(true);
      }
     
      /*
       * (non-Javadoc)
       * @see android.support.v4.app.Fragment#onDetach()
       * 
       * Set the callback to null so we don't accidentally leak the 
       * Activity instance.
       */
      @Override
      public void onDetach() {
        super.onDetach();
        if(this.boundActivity != null) {
            lastActivity = boundActivity;
        }
        if(currentTask != null) {
            Log.i("CommCareUI", "Detaching activity from current task: " + this.currentTask);
            currentTask.disconnect();
            unlock();
        }
      }

    public void cancelTask() {
        if(currentTask != null) {
            currentTask.cancel(false);
        }
    }

    private WakeLock wakelock;

    public synchronized void wakelock(int lockLevel) {
        if(wakelock != null) {
            if(wakelock.isHeld()) {
                wakelock.release();
            }
        }
        PowerManager pm = (PowerManager) boundActivity.getSystemService(Context.POWER_SERVICE);
        wakelock = pm.newWakeLock(lockLevel, "CommCareLock");
        wakelock.acquire();
    }

    public synchronized void unlock() {
        if(wakelock != null) {
            wakelock.release();
            wakelock = null;
        }

    }
}