在GridView中展示sd卡中的图片

package blog.android.sdcard;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.AdapterView.OnItemClickListener;

/**
 * Displays images from an SD card.
 */
public class SDCardImagesActivity extends Activity {

    /**
     * Cursor used to access the results from querying for images on the SD card.
     */
    private Cursor cursor;
    /*
     * Column index for the Thumbnails Image IDs.
     */
    private int columnIndex;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.sdcard);

        // Set up an array of the Thumbnail Image ID column we want
        String[] projection = {MediaStore.Images.Thumbnails._ID};
        // Create the cursor pointing to the SDCard
        cursor = managedQuery( MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI,
                projection, // Which columns to return
                null,       // Return all rows
                null,
                MediaStore.Images.Thumbnails.IMAGE_ID);
        // Get the column index of the Thumbnails Image ID
        columnIndex = cursor.getColumnIndexOrThrow(MediaStore.Images.Thumbnails._ID);

        GridView sdcardImages = (GridView) findViewById(R.id.sdcard);
        sdcardImages.setAdapter(new ImageAdapter(this));

        // Set up a click listener
        sdcardImages.setOnItemClickListener(new OnItemClickListener() {
            public void onItemClick(AdapterView parent, View v, int position, long id) {
                // Get the data location of the image
                String[] projection = {MediaStore.Images.Media.DATA};
                cursor = managedQuery( MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
                        projection, // Which columns to return
                        null,       // Return all rows
                        null,
                        null);
                columnIndex = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
                cursor.moveToPosition(position);
                // Get image filename
                String imagePath = cursor.getString(columnIndex);
                // Use this path to do further processing, i.e. full screen display
            }
        });
    }

    /**
     * Adapter for our image files.
     */
    private class ImageAdapter extends BaseAdapter {

        private Context context;

        public ImageAdapter(Context localContext) {
            context = localContext;
        }

        public int getCount() {
            return cursor.getCount();
        }
        public Object getItem(int position) {
            return position;
        }
        public long getItemId(int position) {
            return position;
        }
        public View getView(int position, View convertView, ViewGroup parent) {
            ImageView picturesView;
            if (convertView == null) {
                picturesView = new ImageView(context);
                // Move cursor to current position
                cursor.moveToPosition(position);
                // Get the current value for the requested column
                int imageID = cursor.getInt(columnIndex);
                // Set the content of the image based on the provided URI
                picturesView.setImageURI(Uri.withAppendedPath(
                        MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI, "" + imageID));
                picturesView.setScaleType(ImageView.ScaleType.FIT_CENTER);
                picturesView.setPadding(8, 8, 8, 8);
                picturesView.setLayoutParams(new GridView.LayoutParams(100, 100));
            }
            else {
                picturesView = (ImageView)convertView;
            }
            return picturesView;
        }
    }
}
The layout of the main activity is shown below:

<?xml version="1.0" encoding="utf-8"?>
<GridView xmlns:android="http://schemas.android.com/apk/res/android" 
    android:id="@+id/sdcard"
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent"
    android:padding="10dp"
    android:verticalSpacing="10dp"
    android:horizontalSpacing="10dp"
    android:numColumns="auto_fit"
    android:columnWidth="90dp"
    android:stretchMode="columnWidth"
    android:gravity="center"
/>

 注意 通常最好是自己在sd卡中已经弄成了一些小图片

MediaStore.Images.Thumbnails._ID 换成MediaStore.Images.Thumbnails.IMAGE_ID 是因为有时候小图片不显示，而且有时候还会出现错误的路径所以使用

cursor = managedQuery( MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI,
projection, // Which columns to return
null,       // Return all rows
null,
MediaStore.Images.Thumbnails.IMAGE_ID);

而不是

cursor = managedQuery( MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI,
projection, // Which columns to return
null,       // Return all rows
null,
null);
main.xml

<?xml version="1.0" encoding="utf-8"?>
<GridView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/sdcard"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:padding="10dp"
    android:verticalSpacing="10dp"
    android:horizontalSpacing="10dp"
    android:numColumns="auto_fit"
    android:columnWidth="90dp"
    android:stretchMode="columnWidth"
    android:gravity="center"
/>

 

改进一下

package blog.android.sdcard2;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.ArrayList;

import android.app.Activity;
import android.content.Context;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.drawable.BitmapDrawable;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Bundle;
import android.provider.MediaStore;
import android.view.Display;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.view.WindowManager;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.AdapterView.OnItemClickListener;

/**
 * Loads images from SD card. 
 * 
 * @author Mihai Fonoage
 *
 */
public class LoadImagesFromSDCardActivity extends Activity implements
OnItemClickListener {
    
    /**
     * Grid view holding the images.
     */
    private GridView sdcardImages;
    /**
     * Image adapter for the grid view.
     */
    private ImageAdapter imageAdapter;
    /**
     * Display used for getting the width of the screen. 
     */
    private Display display;

    /**
     * Creates the content view, sets up the grid, the adapter, and the click listener.
     * 
     * @see android.app.Activity#onCreate(android.os.Bundle)
     */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);        
        // Request progress bar
        requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
        setContentView(R.layout.sdcard);

        display = ((WindowManager) getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();

        setupViews();

        loadImages();
    }

    /**
     * Free up bitmap related resources.
     */
    protected void onDestroy() {
        super.onDestroy();
        final GridView grid = sdcardImages;
        final int count = grid.getChildCount();
        ImageView v = null;
        for (int i = 0; i < count; i++) {
            v = (ImageView) grid.getChildAt(i);
            ((BitmapDrawable) v.getDrawable()).setCallback(null);
        }
    }
    /**
     * Setup the grid view.
     */
    private void setupViews() {
        sdcardImages = (GridView) findViewById(R.id.sdcard);
        sdcardImages.setNumColumns(display.getWidth()/95);
        sdcardImages.setClipToPadding(false);
        sdcardImages.setOnItemClickListener(LoadImagesFromSDCardActivity.this);
        imageAdapter = new ImageAdapter(getApplicationContext()); 
        sdcardImages.setAdapter(imageAdapter);
    }
    /**
     * Load images.
     */
    private void loadImages() {
        final Object data = getLastNonConfigurationInstance();
        if (data == null) {
            new LoadImagesFromSDCard().execute();
        } else {
            final LoadedImage[] photos = (LoadedImage[]) data;
            if (photos.length == 0) {
                new LoadImagesFromSDCard().execute();
            }
            for (LoadedImage photo : photos) {
                addImage(photo);
            }
        }
    }
    /**
     * Add image(s) to the grid view adapter.
     * 
     * @param value Array of LoadedImages references
     */
    private void addImage(LoadedImage... value) {
        for (LoadedImage image : value) {
            imageAdapter.addPhoto(image);
            imageAdapter.notifyDataSetChanged();
        }
    }
    
    /**
     * Save bitmap images into a list and return that list. 
     * 
     * @see android.app.Activity#onRetainNonConfigurationInstance()
     */
    @Override
    public Object onRetainNonConfigurationInstance() {
        final GridView grid = sdcardImages;
        final int count = grid.getChildCount();
        final LoadedImage[] list = new LoadedImage[count];

        for (int i = 0; i < count; i++) {
            final ImageView v = (ImageView) grid.getChildAt(i);
            list[i] = new LoadedImage(((BitmapDrawable) v.getDrawable()).getBitmap());
        }

        return list;
    }
    /**
     * Async task for loading the images from the SD card. 
     * 
     * @author Mihai Fonoage
     *
     */
    class LoadImagesFromSDCard extends AsyncTask<Object, LoadedImage, Object> {
        
        /**
         * Load images from SD Card in the background, and display each image on the screen. 
         *  
         * @see android.os.AsyncTask#doInBackground(Params[])
         */
        @Override
        protected Object doInBackground(Object... params) {
            setProgressBarIndeterminateVisibility(true); 
            Bitmap bitmap = null;
            Bitmap newBitmap = null;
            Uri uri = null;            

            // Set up an array of the Thumbnail Image ID column we want
            String[] projection = {MediaStore.Images.Thumbnails._ID};
            // Create the cursor pointing to the SDCard
            Cursor cursor = managedQuery( MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI,
                    projection, // Which columns to return
                    null,       // Return all rows
                    null,       
                    null); 
            int columnIndex = cursor.getColumnIndexOrThrow(MediaStore.Images.Thumbnails._ID);
            int size = cursor.getCount();
            // If size is 0, there are no images on the SD Card.
            if (size == 0) {
                //No Images available, post some message to the user
            }
            int imageID = 0;
            for (int i = 0; i < size; i++) {
                cursor.moveToPosition(i);
                imageID = cursor.getInt(columnIndex);
                uri = Uri.withAppendedPath(MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI, "" + imageID);
                try {
                    bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(uri));
                    if (bitmap != null) {
                        newBitmap = Bitmap.createScaledBitmap(bitmap, 70, 70, true);
                        bitmap.recycle();
                        if (newBitmap != null) {
                            publishProgress(new LoadedImage(newBitmap));
                        }
                    }
                } catch (IOException e) {
                    //Error fetching image, try to recover
                }
            }
            cursor.close();
            return null;
        }
        /**
         * Add a new LoadedImage in the images grid.
         *
         * @param value The image.
         */
        @Override
        public void onProgressUpdate(LoadedImage... value) {
            addImage(value);
        }
        /**
         * Set the visibility of the progress bar to false.
         * 
         * @see android.os.AsyncTask#onPostExecute(java.lang.Object)
         */
        @Override
        protected void onPostExecute(Object result) {
            setProgressBarIndeterminateVisibility(false);
        }
    }

    /**
     * Adapter for our image files. 
     * 
     * @author Mihai Fonoage
     *
     */
    class ImageAdapter extends BaseAdapter {

        private Context mContext; 
        private ArrayList<LoadedImage> photos = new ArrayList<LoadedImage>();

        public ImageAdapter(Context context) { 
            mContext = context; 
        } 

        public void addPhoto(LoadedImage photo) { 
            photos.add(photo); 
        } 

        public int getCount() { 
            return photos.size(); 
        } 

        public Object getItem(int position) { 
            return photos.get(position); 
        } 

        public long getItemId(int position) { 
            return position; 
        } 

        public View getView(int position, View convertView, ViewGroup parent) { 
            final ImageView imageView; 
            if (convertView == null) { 
                imageView = new ImageView(mContext); 
            } else { 
                imageView = (ImageView) convertView; 
            } 
            imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);
            imageView.setPadding(8, 8, 8, 8);
            imageView.setImageBitmap(photos.get(position).getBitmap());
            return imageView; 
        } 
    }

    /**
     * A LoadedImage contains the Bitmap loaded for the image.
     */
    private static class LoadedImage {
        Bitmap mBitmap;

        LoadedImage(Bitmap bitmap) {
            mBitmap = bitmap;
        }

        public Bitmap getBitmap() {
            return mBitmap;
        }
    }
    /**
     * When an image is clicked, load that image as a puzzle. 
     */
    public void onItemClick(AdapterView<?> parent, View v, int position, long id) {        
        int columnIndex = 0;
        String[] projection = {MediaStore.Images.Media.DATA};
        Cursor cursor = managedQuery( MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI,
                projection,
                null, 
                null, 
                null);
        if (cursor != null) {
            columnIndex = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
            cursor.moveToPosition(position);
            String imagePath = cursor.getString(columnIndex); 

            FileInputStream is = null;
            BufferedInputStream bis = null;
            try {
                is = new FileInputStream(new File(imagePath));
                bis = new BufferedInputStream(is);
                Bitmap bitmap = BitmapFactory.decodeStream(bis);
                Bitmap useThisBitmap = Bitmap.createScaledBitmap(bitmap, parent.getWidth(), parent.getHeight(), true);
                bitmap.recycle();
                //Display bitmap (useThisBitmap)
            } 
            catch (Exception e) {
                //Try to recover
            }
            finally {
                try {
                    if (bis != null) {
                        bis.close();
                    }
                    if (is != null) {
                        is.close();
                    }
                    cursor.close();
                    projection = null;
                } catch (Exception e) {
                }
            }
        }
    }

}

 

评论

4 楼 星星cnuie 2012-08-01  

您好 运行您的程序 可是显示的SD卡的图片不全 而且进行添加或删除图片的调整后 能够显示的图片更少了 最后没有了……请问是为什么、？

3 楼 xunhuan01 2012-06-29  

columnIndex = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
((WindowManager) getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();  这都是什么啊

2 楼 wgsddfe 2011-09-21  

运行您的照片，怎么发现点了一张照片之后，显示的是另外一张啊

1 楼 JACKDG2010 2011-09-03  

请问楼主的布局文件是怎样写的？
     我的程序怎么老报找不到GridView?