ImageGridFragment.java

/*
 *    Copyright (C) 2016 Amit Shekhar
 *    Copyright (C) 2011 Android Open Source Project
 *
 *    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.networking.fragments;

import android.annotation.TargetApi;
import android.content.Context;
import android.os.Build;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.TypedValue;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewTreeObserver;
import android.widget.AbsListView;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;

import com.androidnetworking.widget.ANImageView;
import com.networking.R;
import com.networking.provider.Images;

/**
 * Created by amitshekhar on 23/03/16.
 */
public class ImageGridFragment extends Fragment implements AdapterView.OnItemClickListener {
    private static final String TAG = "ImageGridFragment";

    private int mImageThumbSize;
    private int mImageThumbSpacing;
    private ImageAdapter mAdapter;

    public ImageGridFragment() {
    }

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

        mImageThumbSize = getResources().getDimensionPixelSize(R.dimen.image_thumbnail_size);
        mImageThumbSpacing = getResources().getDimensionPixelSize(R.dimen.image_thumbnail_spacing);
        mAdapter = new ImageAdapter(getActivity());

    }

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

        final View v = inflater.inflate(R.layout.image_grid_fragment, container, false);
        final GridView mGridView = (GridView) v.findViewById(R.id.gridView);
        mGridView.setAdapter(mAdapter);
        mGridView.setOnItemClickListener(this);
        mGridView.getViewTreeObserver().addOnGlobalLayoutListener(
                new ViewTreeObserver.OnGlobalLayoutListener() {
                    @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
                    @Override
                    public void onGlobalLayout() {
                        if (mAdapter.getNumColumns() == 0) {
                            final int numColumns = (int) Math.floor(
                                    mGridView.getWidth() / (mImageThumbSize + mImageThumbSpacing));
                            if (numColumns > 0) {
                                final int columnWidth =
                                        (mGridView.getWidth() / numColumns) - mImageThumbSpacing;
                                mAdapter.setNumColumns(numColumns);
                                mAdapter.setItemHeight(columnWidth);

                                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
                                    mGridView.getViewTreeObserver()
                                            .removeOnGlobalLayoutListener(this);
                                } else {
                                    mGridView.getViewTreeObserver()
                                            .removeGlobalOnLayoutListener(this);
                                }
                            }
                        }
                    }
                });

        return v;
    }

    @Override
    public void onResume() {
        super.onResume();
        mAdapter.notifyDataSetChanged();
    }

    @Override
    public void onPause() {
        super.onPause();
    }

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

    @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
    @Override
    public void onItemClick(AdapterView<?> parent, View v, int position, long id) {

    }


    private class ImageAdapter extends BaseAdapter {

        private final Context mContext;
        private int mItemHeight = 0;
        private int mNumColumns = 0;
        private int mActionBarHeight = 0;
        private GridView.LayoutParams mImageViewLayoutParams;

        public ImageAdapter(Context context) {
            super();
            mContext = context;
            mImageViewLayoutParams = new GridView.LayoutParams(
                    ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
            TypedValue tv = new TypedValue();
            if (context.getTheme().resolveAttribute(
                    android.R.attr.actionBarSize, tv, true)) {
                mActionBarHeight = TypedValue.complexToDimensionPixelSize(
                        tv.data, context.getResources().getDisplayMetrics());
            }
        }

        @Override
        public int getCount() {
            if (getNumColumns() == 0) {
                return 0;
            }

            return Images.imageThumbUrls.length + mNumColumns;
        }

        @Override
        public Object getItem(int position) {
            return position < mNumColumns ?
                    null : Images.imageThumbUrls[position - mNumColumns];
        }

        @Override
        public long getItemId(int position) {
            return position < mNumColumns ? 0 : position - mNumColumns;
        }

        @Override
        public int getViewTypeCount() {
            return 2;
        }

        @Override
        public int getItemViewType(int position) {
            return (position < mNumColumns) ? 1 : 0;
        }

        @Override
        public boolean hasStableIds() {
            return true;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup container) {
            if (position < mNumColumns) {
                if (convertView == null) {
                    convertView = new View(mContext);
                }
                convertView.setLayoutParams(new AbsListView.LayoutParams(
                        ViewGroup.LayoutParams.MATCH_PARENT, mActionBarHeight));
                return convertView;
            }

            ANImageView imageView;
            if (convertView == null) {
                imageView = new ANImageView(mContext);
                imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
                imageView.setLayoutParams(mImageViewLayoutParams);
            } else {
                imageView = (ANImageView) convertView;
            }

            if (imageView.getLayoutParams().height != mItemHeight) {
                imageView.setLayoutParams(mImageViewLayoutParams);
            }
            imageView.setDefaultImageResId(R.drawable.ic_toys_black_24dp);
            imageView.setErrorImageResId(R.drawable.ic_error_outline_black_24dp);
            imageView.setImageUrl(Images.imageThumbUrls[position - mNumColumns]);

            return imageView;
        }

        public void setItemHeight(int height) {
            if (height == mItemHeight) {
                return;
            }
            mItemHeight = height;
            mImageViewLayoutParams =
                    new GridView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, mItemHeight);
            notifyDataSetChanged();
        }

        public void setNumColumns(int numColumns) {
            mNumColumns = numColumns;
        }

        public int getNumColumns() {
            return mNumColumns;
        }
    }
}