package com.test.gridview;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.View;

import android.widget.AdapterView;

import android.widget.GridView;

import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        GridView gridview = (GridView) findViewById(R.id.gridview);

        gridview.setAdapter(new ImageAdapter(this));

        gridview.setOnItemClickListener(new AdapterView.OnItemClickListener() {

            public void onItemClick(AdapterView<?> parent, View v,

                                    int position, long id) {

                Toast.makeText(MainActivity.this, "" + position,

                        Toast.LENGTH_SHORT).show();

            }

        });

    }

}

package com.test.gridview;

import android.content.Context;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.view.View;

import android.view.ViewGroup;

import android.widget.BaseAdapter;

import android.widget.GridView;

import android.widget.ImageView;

import java.util.List;

import java.util.Map;

/**

 * Created by 1 on 2016/4/17.

 */

public class ImageAdapter extends BaseAdapter {

    private Context mContext;

    public ImageAdapter(Context c) {

        mContext = c;

    }

    public int getCount() {

        return imagePath.size();

    }

    public Object getItem(int position) {

        return null;

    }

    public long getItemId(int position) {

        return 0;

    }

    // create a new ImageView for each item referenced by the Adapter

    public View getView(int position, View convertView, ViewGroup parent) {

        ImageView imageView;

        if (convertView == null) {

            // if it's not recycled, initialize some attributes

            imageView = new ImageView(mContext);

            imageView.setLayoutParams(new GridView.LayoutParams(85, 85));

            imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);

            imageView.setPadding(8, 8, 8, 8);

        } else {

            imageView = (ImageView) convertView;

        }

        Bitmap bitmap = BitmapFactory.decodeFile(imagePath.get(position).get(FileUtils.IMAGE_PATH));

        imageView.setImageBitmap(bitmap);

        return imageView;

    }

    private List<Map<String, String>> imagePath = FileUtils.getFiles(FileUtils.SDPATH);

}

package com.test.gridview;

import android.os.Environment;

import java.io.File;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

/**

 * Created by 1 on 2016/4/17.

 */

public class FileUtils {

    public static String[] imageFormatSet = {"jpg", "png", "gif"};

    public static String SDPATH = Environment.getExternalStorageDirectory() + "/00Meeting/";

    public static String IMAGE_NAME = "imageName";

    public static String IMAGE_PATH = "imagePath";

    /**

     * 判断是否是图片文件

     *

     * @param path

     * @return

     */

    public static boolean isImageFile(String path) {

        for (String format : imageFormatSet) {

            if (path.endsWith(format)) {

                return true;

            }

        }

        return false;

    }

    public static List<Map<String, String>> getFiles(String path) {

        List<Map<String, String>> pathList = new ArrayList<>();

        File file = new File(path);

        File[] files = file.listFiles();

        for (File f : files) {

            if (f.isDirectory()) {

                getFiles(f.getAbsolutePath());

            } else {

                if (isImageFile(f.getPath())) {

                    Map<String, String> map = new HashMap<>();

                    map.put(FileUtils.IMAGE_NAME, f.getName());

                    map.put(FileUtils.IMAGE_PATH, f.getPath());

                    pathList.add(map);

                }

            }

        }

        return pathList;

    }

}