Fix bug of mvp delegate

FixedMvpDelegate.java

package com.arellomobile.mvp;

import java.util.ArrayList;
import java.util.List;

import android.os.Bundle;

import com.arellomobile.mvp.presenter.PresenterType;

/**
 * Date: 18-Dec-15
 * Time: 13:51
 * <p>
 * This class represents a delegate which you can use to extend Mvp's support to any class.
 * <p>
 * When using an {@link FixedMvpDelegate}, lifecycle methods which should be proxied to the delegate:
 * <ul>
 * <li>{@link #onCreate(Bundle)}</li>
 * <li>{@link #onStart()}</li>
 * <li>{@link #onSaveInstanceState(android.os.Bundle)}</li>
 * <li>{@link #onStop()}</li>
 * <li>{@link #onDestroy()}</li>
 * </ul>
 * <p>
 * Every {@link Object} can only be linked with one {@link FixedMvpDelegate} instance,
 * so the instance returned from {@link #FixedMvpDelegate(Object)}} should be kept
 * until the Object is destroyed.
 *
 * @author Alexander Blinov
 */
public class FixedMvpDelegate<Delegated>
{
	private static final String KEY_TAGS = "com.arellomobile.mvp.MvpDelegate.KEY_TAGS";

	private String mKeyTags = KEY_TAGS;
	private String mDelegateTag;
	private final Delegated mDelegated;
	private int mStateSavedCounter;
	private boolean mIsAttached;
	private FixedMvpDelegate mParentDelegate;
	private List<MvpPresenter<? super Delegated>> mPresenters;
	private List<FixedMvpDelegate> mChildDelegates;
	private Bundle mBundle;

	public FixedMvpDelegate(Delegated delegated)
	{
		mDelegated = delegated;
		mChildDelegates = new ArrayList<>();
	}

	public void setParentDelegate(FixedMvpDelegate delegate, String childId)
	{
		if (mBundle != null)
		{
			throw new IllegalStateException("You should call setParentDelegate() before first onCreate()");
 		}
		if (mChildDelegates != null && mChildDelegates.size() > 0)
		{
			throw new IllegalStateException("You could not set parent delegate when it already has child presenters");
		}

		mParentDelegate = delegate;
		mKeyTags = mParentDelegate.mKeyTags + "$" + childId;

		delegate.addChildDelegate(this);
	}

	private void addChildDelegate(FixedMvpDelegate delegate)
	{
		mChildDelegates.add(delegate);
	}

	/**
	 * <p>Similar like {@link #onCreate(Bundle)}. But this method try to get saved
	 * state from parent presenter before get presenters</p>
	 */
	public void onCreate()
	{
		Bundle bundle = new Bundle();
		if (mParentDelegate != null)
		{
			bundle = mParentDelegate.mBundle;
		}

		onCreate(bundle);
	}

	/**
	 * <p>Get(or create if not exists) presenters for delegated object and bind
	 * them to this object fields</p>
	 *
	 * @param bundle with saved state
	 */
	public void onCreate(Bundle bundle)
	{
		mStateSavedCounter = 0;
		mIsAttached = false;
		mBundle = bundle;

		//get base tag for presenters
		if (bundle == null || !mBundle.containsKey(mKeyTags))
		{
			mDelegateTag = generateTag();
		}
		else
		{
			mDelegateTag = bundle.getString(mKeyTags);
		}

		//bind presenters to view
		mPresenters = MvpFacade.getInstance().getMvpProcessor().getMvpPresenters(mDelegated, mDelegateTag);

		for (FixedMvpDelegate childDelegate : mChildDelegates)
		{
			childDelegate.onCreate(bundle);
		}
	}

	/**
	 * <p>Attach delegated object as view to presenter fields of this object.
	 * If delegate did not enter at {@link #onCreate(Bundle)}(or
	 * {@link #onCreate()}) before this method, then view will not be attached to
	 * presenters</p>
	 */
	public void onStart()
	{
		mStateSavedCounter = 0;

		for (MvpPresenter<? super Delegated> presenter : mPresenters)
		{
			if (mIsAttached && presenter.getAttachedViews().contains(mDelegated))
			{
				continue;
			}

			presenter.attachView(mDelegated);
		}

		for (FixedMvpDelegate<?> childDelegate : mChildDelegates)
		{
			childDelegate.onStart();
		}

		mIsAttached = true;
	}

	public void onStop()
	{
		for (FixedMvpDelegate<?> childDelegate : mChildDelegates)
		{
			childDelegate.onStop();
		}
	}

	/**
	 * <p>Detach delegated object from their presenters and destroy presenters if
	 * they are not needed.</p>
	 */
	public void onDestroy()
	{
		for (MvpPresenter<? super Delegated> presenter : mPresenters)
		{
			presenter.detachView(mDelegated);
		}

		if (mStateSavedCounter == 0)
		{
			destroyPresenters();
		}
		mStateSavedCounter = Math.max(mStateSavedCounter - 1, 0);

		for (FixedMvpDelegate<?> childDelegate : mChildDelegates)
		{
			childDelegate.onDestroy();
		}
	}

	/**
	 * Save presenters tag prefix to save state for restore presenters at future after delegate recreate
	 * @param outState out state from Android component
	 */
	public void onSaveInstanceState(Bundle outState)
	{
		mStateSavedCounter++;

		outState.putString(mKeyTags, mDelegateTag);

		for (FixedMvpDelegate childDelegate : mChildDelegates)
		{
			childDelegate.onSaveInstanceState(outState);
		}
	}

	private void destroyPresenters()
	{
		PresenterStore presenterStore = MvpFacade.getInstance().getPresenterStore();

		for (MvpPresenter<?> presenter : mPresenters)
		{
			if (presenter.getPresenterType() == PresenterType.LOCAL)
			{
				presenter.onDestroy();
				presenterStore.remove(PresenterType.LOCAL, presenter.getTag(), presenter.getClass());
			}
		}
	}

	/**
	 * @return generated tag in format: Delegated_class_full_name$MvpDelegate@hashCode
	 *
	 * example: com.arellomobile.com.arellomobile.mvp.sample.SampleFragment$MvpDelegate@32649b0
	 */
	private String generateTag()
	{
		return mDelegated.getClass().getName() + "$" + getClass().getSimpleName()+ toString().replace(getClass().getName(),"");
	}
}

MvpFragment

package net.senneco.mvpfragment;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.arellomobile.mvp.FixedMvpDelegate;

/**
 * Created by senneco on 09.06.2016
 */

public class MvpFragment extends Fragment
{
	private Bundle mTemporaryBundle;// required for view destroy/restore
	private FixedMvpDelegate<? extends MvpFragment> mFixedMvpDelegate;

	public MvpFragment()
	{
		mTemporaryBundle = null;
	}

	public void onCreate(Bundle savedInstanceState)
	{
		super.onCreate(savedInstanceState);

		getMvpDelegate().onCreate(savedInstanceState);
	}

	@Override
	public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
	{
		if (mTemporaryBundle != null)
		{
			getMvpDelegate().onCreate(mTemporaryBundle);
			mTemporaryBundle = null;
		}

		return super.onCreateView(inflater, container, savedInstanceState);
	}

	public void onStart()
	{
		super.onStart();

		getMvpDelegate().onStart();
	}

	public void onSaveInstanceState(Bundle outState)
	{
		super.onSaveInstanceState(outState);

		getMvpDelegate().onSaveInstanceState(outState);
	}

	public void onStop()
	{
		super.onStop();

		getMvpDelegate().onStop();
	}

	@Override
	public void onDestroyView()
	{
		super.onDestroyView();

		mTemporaryBundle = new Bundle();
		getMvpDelegate().onSaveInstanceState(mTemporaryBundle);

		getMvpDelegate().onDestroy();
	}

	@Override
	public void onDestroy()
	{
		super.onDestroy();
		
		getMvpDelegate().onDestroy();
	}

	public FixedMvpDelegate getMvpDelegate()
	{
		if (mFixedMvpDelegate == null)
		{
			mFixedMvpDelegate = new FixedMvpDelegate<>(this);
		}

		return mFixedMvpDelegate;
	}
}