ContractFragment.java

package com.distantfuture.videos.misc;

import android.app.Activity;
import android.app.Fragment;

/* Base fragment to ensure the parent activity implements a contract interface. */
public abstract class ContractFragment<T> extends Fragment {
  private T mContract;

  @Override
  public void onAttach(Activity activity) {
    try {
      mContract = (T) activity;
    } catch (ClassCastException e) {
      throw new IllegalStateException(activity.getClass().getSimpleName()
          + " does not implement " + getClass().getSimpleName() + "'s contract interface.", e);
    }
    super.onAttach(activity);
  }

  @Override
  public void onDetach() {
    super.onDetach();
    mContract = null;
  }

  public final T getContract() {
    return mContract;
  }
}