org.solovyev.android.messenger.FragmentUi.java Source code

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Here is the source code for org.solovyev.android.messenger.FragmentUi.java

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/*
 * Copyright 2014 serso aka se.solovyev
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.solovyev.android.messenger;

import android.os.Bundle;
import android.support.v4.app.Fragment;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;

public class FragmentUi {

    @Nonnull
    private final Fragment fragment;

    /**
     * Last saved instance state (the last state which has been passed through onCreate method)
     * <p/>
     * Problem: When fragment is in back stack and has not been shown during activity lifecycle then
     * onSaveInstanceState() saves nothing on activity destruction (as no view has been created). If later we return to this fragment using back button we loose state.
     * <p/>
     * Solution: Save last state and if fragment hsa not been shown - use it.
     */
    @Nullable
    private Bundle lastSavedInstanceState;

    private boolean viewWasCreated = false;

    public FragmentUi(@Nonnull Fragment fragment) {
        this.fragment = fragment;
    }

    @Nonnull
    public Fragment getFragment() {
        return fragment;
    }

    public boolean wasViewCreated() {
        return viewWasCreated;
    }

    /*
    **********************************************************************
    *
    *                           LIFECYCLE
    *
    **********************************************************************
    */

    public void onCreate(@Nullable Bundle savedInstanceState) {
        lastSavedInstanceState = savedInstanceState;
        viewWasCreated = false;
    }

    public void onViewCreated() {
        viewWasCreated = true;
    }

    public void copyLastSavedInstanceState(@Nonnull Bundle outState) {
        if (lastSavedInstanceState != null) {
            outState.putAll(lastSavedInstanceState);
        }
    }

    public void clearLastSavedInstanceState() {
        lastSavedInstanceState = null;
    }
}