net.oremland.rss.reader.fragments.BaseListFragment.java Source code

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Here is the source code for net.oremland.rss.reader.fragments.BaseListFragment.java

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/***********************************************************************************************************************
 * ==========================================
 *
 * Copyright (C) 2013 by Paul Oremland
 * http://www.linkedin.com/in/pauloremland
 * https://github.com/poremland
 *
 ***********************************************************************************************************************
 *
 * 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 net.oremland.rss.reader.fragments;

import net.oremland.rss.reader.R;

import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.*;
import android.text.*;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.*;

import java.util.*;
import java.util.Map.Entry;

import net.oremland.rss.reader.helpers.*;
import net.oremland.rss.reader.models.*;

import org.json.JSONArray;

public abstract class BaseListFragment<TModel extends BaseModel, TAdapter extends BaseAdapter>
        extends ListFragment {
    private final static String MODELS_KEY = "models";
    private ListView list;
    private TAdapter adapter;
    private TreeMap<String, TModel> models;

    public interface OnModelsLoadedListener<TModel extends BaseModel> {
        public void onModelsLoaded(List<TModel> models);
    }

    public BaseListFragment() {
        // we use state management and need the onSavedInstanceState
        // and onCreate, onCreateView, and onActivityCreated methods
        // to be called for the lifecycle events of the fragment.
        setRetainInstance(false);
    }

    protected abstract void loadModelList(OnModelsLoadedListener<TModel> listener);

    protected abstract void displayModel(TModel model);

    protected abstract TAdapter createAdapter();

    protected abstract int getLayoutId();

    protected Comparator getListComparator() {
        return Collections.reverseOrder(Collections.reverseOrder());
    }

    protected void shouldUpdateModelList() {
        if (this.clearModels() || this.clearAdapter()) {
            this.updateListView();
        }
    }

    private boolean clearAdapter() {
        if (this.adapter != null) {
            this.adapter.clear();
            return true;
        }
        return false;
    }

    private boolean clearModels() {
        if (this.models != null) {
            this.models.clear();
            return true;
        }
        return false;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        return inflater.inflate(this.getLayoutId(), container, false);
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        this.initializeList();
        this.setFieldsFromBundle(this.getArguments());
        this.models = this.getSavedModels(savedInstanceState);
        this.ensureModelsTreeMapIsInitialized();
    }

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

        this.load();
    }

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

        this.saveModels(outState);
    }

    public void load() {
        if (!this.didLoadExistingModels() || !this.canCacheModels()) {
            this.setProgressBarVisibility(View.VISIBLE);
            this.loadModelList(new OnModelsLoadedListener<TModel>() {
                @Override
                public void onModelsLoaded(List<TModel> models) {
                    TreeMap<String, TModel> map = getModelMap(models);
                    setModels(map);
                    updateListView();
                }
            });
        }
    }

    protected boolean canCacheModels() {
        return true;
    }

    private boolean didLoadExistingModels() {
        if (this.hasModels()) {
            updateListView();
            return true;
        }
        return false;
    }

    private boolean hasModels() {
        return this.models != null && this.models.size() > 0;
    }

    private void initializeList() {
        this.list = getListView();
        this.list.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
        this.list.setOnItemClickListener(this.getListViewClickListener());
    }

    private OnItemClickListener getListViewClickListener() {
        return new OnItemClickListener() {
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                list.setItemChecked(position, true);
                list.setSelection(position);
                TModel item = (TModel) parent.getAdapter().getItem(position);
                displayModel(item);
            }
        };
    }

    protected void setFieldsFromBundle(Bundle arguments) {
    }

    private void ensureModelsTreeMapIsInitialized() {
        if (this.models == null) {
            this.models = this.createTreeMap();
        }
    }

    private TreeMap<String, TModel> createTreeMap() {
        return new TreeMap<String, TModel>(this.getListComparator());
    }

    protected void removeModel(String name) {
        this.ensureModelsTreeMapIsInitialized();
        this.models.remove(name);
        this.updateListView();
    }

    private TModel getModel(String name) {
        this.ensureModelsTreeMapIsInitialized();
        return this.models.get(name);
    }

    private TModel getModel(int position) {
        return (TModel) this.adapter.getItem(position);
    }

    private void setModels(TreeMap<String, TModel> models) {
        this.models = models;
    }

    private void updateListView() {
        this.ensureModelsTreeMapIsInitialized();
        this.updateListView(this.models);
        this.setProgressBarVisibility(View.GONE);
    }

    private void updateListView(TreeMap<String, TModel> items) {
        if (getActivity() != null) {
            this.adapter = this.createAdapter();
            List<TModel> models = this.getModelList(items);
            this.adapter.setModels(models);
            if (this.list != null && !this.isDetached()) {
                this.list.setAdapter(this.adapter);
            }
        }
    }

    private List<TModel> getModelList(TreeMap<String, TModel> items) {
        List<TModel> models = new ArrayList<TModel>();
        for (Map.Entry<String, TModel> item : items.entrySet()) {
            models.add(item.getValue());
        }
        return models;
    }

    private TreeMap<String, TModel> getModelMap(List<TModel> models) {
        TreeMap<String, TModel> map = this.createTreeMap();
        for (TModel model : models) {
            map.put(model.getKey(), model);
        }
        return map;
    }

    private void setProgressBarVisibility(int visible) {
        if (this.hasProgressBar()) {
            getView().findViewById(R.id.progressContainer).setVisibility(visible);
        }
    }

    private boolean hasProgressBar() {
        return getView() != null && getView().findViewById(R.id.progressContainer) != null;
    }

    private void saveModels(Bundle outState) {
        if (this.models != null && outState != null) {
            String serializedModels = ObjectSerializer.toString(this.models);
            if (serializedModels != null) {
                outState.putString(MODELS_KEY, serializedModels);
            }
        }
    }

    private TreeMap<String, TModel> getSavedModels(Bundle savedInstanceState) {
        if (savedInstanceState != null) {
            String s = savedInstanceState.getString(MODELS_KEY, "");
            if (!TextUtils.isEmpty(s)) {
                return ObjectSerializer.fromString(s);
            }
        }
        return this.models;
    }
}