Below is a sample custom achievement. It uses an alert dialog to display the achievement information. This is meant to illustrate how to make custom achievement API calls and shouldn't be used in a real app.

DialogAchievementActivity.java

package test.com.sessionm.app;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.util.Log;
import com.sessionm.api.AchievementData;
import com.sessionm.api.AchievementActivity;
import com.sessionm.api.AchievementActivityIllegalStateException;
import com.sessionm.api.SessionM;
 
public class DialogAchievementActivity extends AchievementActivity {
  private AlertDialog dialog;
  private Activity presentingActivity;
  public DialogAchievementActivity(Activity activity, AchievementData achievement) {
    super(achievement);
    presentingActivity = activity;
    AlertDialog.Builder builder = new AlertDialog.Builder(activity);
    builder.setTitle(achievement.getName());
    builder.setMessage(String.format("%s\n+%d mPoints", achievement.getMessage(), achievement.getMpointValue()));
    builder.setPositiveButton("Claim", new DialogInterface.OnClickListener() {
      @Override
      public void onClick(DialogInterface dialog, int which) {
        DialogAchievementActivity.this.claim();
      }
    });
    builder.setNegativeButton("Dismiss", new DialogInterface.OnClickListener() {
      @Override
      public void onClick(DialogInterface dialog, int which) {
        DialogAchievementActivity.this.dismiss();
      }
    });
    dialog = builder.create();
  }
  
  public void present() {
    if (dialog != null && !dialog.isShowing()) {
      presentingActivity.runOnUiThread(new Runnable() {
        public void run() {
          dialog.show();
          try {
          DialogAchievementActivity.this.notifyPresented();
          } catch (AchievementActivityIllegalStateException e) {
            Log.e(SessionM.TAG, "Exception while presenting native achievement." + e);
          }
        }
      });
    }
  }
   
  public void claim() {
    presentingActivity.runOnUiThread(new Runnable() {
      public void run() {
        dialog.dismiss();
          try {
            DialogAchievementActivity.this.notifyDismissed(AchievementDismissType.CLAIMED);
          } catch (AchievementActivityIllegalStateException e) {
            Log.e(SessionM.TAG, "Exception while claiming native achievement." + e);
          }
        }
    });
  }
  public void dismiss() {
    presentingActivity.runOnUiThread(new Runnable() {
      public void run() {
        dialog.dismiss();
        try {
          DialogAchievementActivity.this.notifyDismissed(AchievementDismissType.CANCELLED);
        } catch (AchievementActivityIllegalStateException e) {
        Log.e(SessionM.TAG, "Exception while dismissing native achievement." + e);
        }
      }
    });
  }
}