MediaGalleryEditFragment.java

package org.wordpress.android.ui.media;

import android.app.Fragment;
import android.database.Cursor;
import android.database.CursorWrapper;
import android.os.Bundle;
import android.util.SparseIntArray;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.LayoutInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;

import com.mobeta.android.dslv.DragSortListView;
import com.mobeta.android.dslv.DragSortListView.DropListener;
import com.mobeta.android.dslv.DragSortListView.RemoveListener;
import com.wellsql.generated.MediaModelTable;

import org.wordpress.android.R;
import org.wordpress.android.WordPress;
import org.wordpress.android.fluxc.model.SiteModel;
import org.wordpress.android.fluxc.store.MediaStore;
import org.wordpress.android.fluxc.tools.FluxCImageLoader;
import org.wordpress.android.util.ListUtils;
import org.wordpress.android.util.ToastUtils;

import java.util.ArrayList;
import java.util.Collections;

import javax.inject.Inject;

/**
 * Fragment where containing a drag-sort listview where the user can drag items
 * to change their position in a media gallery
 */
public class MediaGalleryEditFragment extends Fragment implements DropListener, RemoveListener {
    private static final String SAVED_MEDIA_IDS = "SAVED_MEDIA_IDS";
    private MediaGalleryAdapter mGridAdapter;
    private ArrayList<Long> mIds;
    private SiteModel mSite;

    @Inject MediaStore mMediaStore;
    @Inject FluxCImageLoader mImageLoader;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ((WordPress) getActivity().getApplication()).component().inject(this);
        updateSiteOrFinishActivity(savedInstanceState);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        super.onCreateView(inflater, container, savedInstanceState);

        mIds = new ArrayList<>();
        if (savedInstanceState != null) {
            mIds = ListUtils.fromLongArray(savedInstanceState.getLongArray(SAVED_MEDIA_IDS));
        }

        mGridAdapter = new MediaGalleryAdapter(getActivity(), R.layout.media_gallery_item, null, true, mImageLoader);

        View view = inflater.inflate(R.layout.media_gallery_edit_fragment, container, false);

        DragSortListView gridView = (DragSortListView) view.findViewById(R.id.edit_media_gallery_gridview);
        gridView.setAdapter(mGridAdapter);
        gridView.setOnCreateContextMenuListener(this);
        gridView.setDropListener(this);
        gridView.setRemoveListener(this);
        refreshGridView();

        return view;
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        if (mIds != null && !mIds.isEmpty()) {
            outState.putLongArray(SAVED_MEDIA_IDS, ListUtils.toLongArray(mIds));
        }
        outState.putSerializable(WordPress.SITE, mSite);
    }

    private void updateSiteOrFinishActivity(Bundle savedInstanceState) {
        if (savedInstanceState == null) {
            if (getArguments() != null) {
                mSite = (SiteModel) getArguments().getSerializable(WordPress.SITE);
            } else {
                mSite = (SiteModel) getActivity().getIntent().getSerializableExtra(WordPress.SITE);
            }
        } else {
            mSite = (SiteModel) savedInstanceState.getSerializable(WordPress.SITE);
        }

        if (mSite == null) {
            ToastUtils.showToast(getActivity(), R.string.blog_not_found, ToastUtils.Duration.SHORT);
            getActivity().finish();
        }
    }

    private void refreshGridView() {
        if (mIds == null || mIds.isEmpty()) {
            mGridAdapter.changeCursor(null);
            return;
        }
        Cursor cursor = mMediaStore.getSiteMediaWithIdsAsCursor(mSite, mIds);
        SparseIntArray positions = mapIdsToCursorPositions(cursor);
        mGridAdapter.swapCursor(new OrderedCursor(cursor, positions));
    }

    private SparseIntArray mapIdsToCursorPositions(Cursor cursor) {
        SparseIntArray positions = new SparseIntArray();
        int size = mIds.size();
        for (int i = 0; i < size; i++) {
            while (cursor.moveToNext()) {
                long mediaId = cursor.getLong(cursor.getColumnIndex(MediaModelTable.MEDIA_ID));
                if (mediaId == mIds.get(i)) {
                    positions.put(i, cursor.getPosition());
                    cursor.moveToPosition(-1);
                    break;
                }
            }
        }
        return positions;
    }

    public void setMediaIds(ArrayList<Long> ids) {
        mIds = ids;
        refreshGridView();
    }

    public ArrayList<Long> getMediaIds() {
        return mIds;
    }

    public void reverseIds() {
        Collections.reverse(mIds);
        refreshGridView();
    }

    private class OrderedCursor extends CursorWrapper {
        final int mPos;
        private final int mCount;

        // a map of custom position to cursor position
        private final SparseIntArray mPositions;

        /**
         * A wrapper to allow for a custom order of items in a cursor *
         */
        public OrderedCursor(Cursor cursor, SparseIntArray positions) {
            super(cursor);
            cursor.moveToPosition(-1);
            mPos = 0;
            mCount = cursor.getCount();
            mPositions = positions;
        }

        @Override
        public boolean move(int offset) {
            return this.moveToPosition(this.mPos + offset);
        }

        @Override
        public boolean moveToNext() {
            return this.moveToPosition(this.mPos + 1);
        }

        @Override
        public boolean moveToPrevious() {
            return this.moveToPosition(this.mPos - 1);
        }

        @Override
        public boolean moveToFirst() {
            return this.moveToPosition(0);
        }

        @Override
        public boolean moveToLast() {
            return this.moveToPosition(this.mCount - 1);
        }

        @Override
        public boolean moveToPosition(int position) {
            return super.moveToPosition(mPositions.get(position));
        }
    }

    @Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
        AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) menuInfo;
        Cursor cursor = mGridAdapter.getCursor();
        if (cursor == null) {
            return;
        }
        cursor.moveToPosition(info.position);
        long mediaId = cursor.getLong(cursor.getColumnIndex(MediaModelTable.MEDIA_ID));

        menu.add(ContextMenu.NONE, mIds.indexOf(mediaId), ContextMenu.NONE, R.string.delete);
    }

    @Override
    public boolean onContextItemSelected(MenuItem item) {
        int index = item.getItemId();
        mIds.remove(index);
        refreshGridView();
        return true;
    }

    @Override
    public void drop(int from, int to) {
        long id = mIds.get(from);
        mIds.remove(id);
        mIds.add(to, id);
        refreshGridView();
    }

    @Override
    public void remove(int position) {
    }
}