SimpleFloatViewManager.java

/**
 * A subclass of the Android ListView component that enables drag
 * and drop re-ordering of list items.
 *
 * Copyright 2012 Carl Bauer
 *
 * 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 com.mobeta.android.dslv;

import android.graphics.Bitmap;
import android.graphics.Point;
import android.graphics.Color;
import android.widget.ListView;
import android.widget.ImageView;
import android.view.View;
import android.util.Log;

/**
 * Simple implementation of the FloatViewManager class. Uses list
 * items as they appear in the ListView to create the floating View.
 */
public class SimpleFloatViewManager implements DragSortListView.FloatViewManager {

    private Bitmap mFloatBitmap;

    private ImageView mImageView;

    private int mFloatBGColor = Color.BLACK;

    protected ListView mListView;

    public SimpleFloatViewManager(ListView lv) {
        mListView = lv;
    }

    public void setBackgroundColor(int color) {
        mFloatBGColor = color;
    }

    /**
     * This simple implementation creates a Bitmap copy of the
     * list item currently shown at ListView <code>position</code>.
     */
    @Override
    public View onCreateFloatView(int position) {
        // Guaranteed that this will not be null? I think so. Nope, got
        // a NullPointerException once...
        View v = mListView.getChildAt(position + mListView.getHeaderViewsCount() - mListView.getFirstVisiblePosition());

        if (v == null) {
            return null;
        }

        v.setPressed(false);

        // Create a copy of the drawing cache so that it does not get
        // recycled by the framework when the list tries to clean up memory
        //v.setDrawingCacheQuality(View.DRAWING_CACHE_QUALITY_HIGH);
        v.setDrawingCacheEnabled(true);
        mFloatBitmap = Bitmap.createBitmap(v.getDrawingCache());
        v.setDrawingCacheEnabled(false);

        if (mImageView == null) {
            mImageView = new ImageView(mListView.getContext());
        }
        mImageView.setBackgroundColor(mFloatBGColor);
        mImageView.setPadding(0, 0, 0, 0);
        mImageView.setImageBitmap(mFloatBitmap);

        return mImageView;
    }

    /**
     * This does nothing
     */
    @Override
    public void onDragFloatView(View floatView, Point position, Point touch) {
        // do nothing
    }

    /**
     * Removes the Bitmap from the ImageView created in
     * onCreateFloatView() and tells the system to recycle it.
     */
    @Override
    public void onDestroyFloatView(View floatView) {
        ((ImageView) floatView).setImageDrawable(null);

        mFloatBitmap.recycle();
        mFloatBitmap = null;
    }

}