安卓中关于图片从网络获取，压缩，上传，下载，缩略图，缓存的一些处理总结（一）

来源：互联网发布：淘宝图片空间手机端编辑：程序博客网时间：2024/06/06 03:43

本帖原创，转发请标记出处。实在是本人一些肤浅的经验之谈，大神可绕行。另外如有不足之处或者可以优化的地方

欢迎指出，万分感谢。只为相互学习和进步。如果能对您有所帮助或者启发，便是我最开心的事。

最近写了类似微信朋友圈的功能，这就涉及到关于图片的处理

图片的处理要考虑用户端的显示和服务器端的存储能力

因此图片要尽可能的清楚又要尽可能的小还要尽可能加载的快缓存与回收的好

这就需做要做很多的工作

先说第一部分：图片的获取

一来自于拍照二来源于相册中选取

1.拍照

思路：调用系统相机拍照，注意拍照权限，在onActivityResult方法中处理得到的Bitmap或者图片地址

public void photo() {    //执行拍照前，应该先判断SD卡是否存在    String SDState = Environment.getExternalStorageState();    if (SDState.equals(Environment.MEDIA_MOUNTED)) {        Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);        /***         * 需要说明一下，以下操作使用照相机拍照，拍照后的图片会存放在相册中的         * 这里使用的这种方式有一个好处就是获取的图片是拍照后的原图         * 如果不实用ContentValues存放照片路径的话，拍照后获取的图片为缩略图不清晰         */        ContentValues values = new ContentValues();        mPhotoUri = this.getContentResolver().insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values);        intent.putExtra(android.provider.MediaStore.EXTRA_OUTPUT, mPhotoUri);        startActivityForResult(intent, TAKE_PICTURE);    } else {        BaseApp.getInstance().showInformation(R.string.network_no_sdcard);    }}

/** * 结果返回调用 * * @param requestCode * @param resultCode * @param data */protected void onActivityResult(int requestCode, int resultCode, Intent data) {    switch (requestCode) {        case TAKE_PICTURE:            if (Bimp.drr.size() < 9 && resultCode == RESULT_OK) {//从拍照回调的结果                if (mPhotoUri == null) {                    BaseApp.getInstance().showInformation(R.string.userinfo_error_select_picture);                } else {                    String[] pojo = {MediaStore.Images.Media.DATA};                    Cursor cursor = getContentResolver().query(mPhotoUri, pojo, null, null, null);                    if (cursor != null) {                        int columnIndex = cursor.getColumnIndexOrThrow(pojo[0]);                        cursor.moveToFirst();                        path = cursor.getString(columnIndex);                        cursor.close();                    }                    Bimp.drr.add(path);                    mPhotoAdapter.update();                }            }            break;        case 101://刷新方法            mPhotoAdapter.update();            break;    }}

2.从相册中选择从系统中得到要存放图片的路径然后用adapter展示再选择（请参看最后专辑帮助类）

import android.app.Activity;import android.graphics.Bitmap;import android.util.Log;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.ImageView;import android.widget.TextView;import com.nostra13.universalimageloader.core.ImageLoader;import java.util.List;import cn.ninebot.ninebot.BaseApp;import cn.ninebot.ninebot.R;public class ImageBucketAdapter extends BaseAdapter {   final String TAG = getClass().getSimpleName();   Activity act;   /**    * 图片集列表    */   List<ImageBucket> dataList;   BitmapCache cache;   BitmapCache.ImageCallback callback = new BitmapCache.ImageCallback() {      @Override      public void imageLoad(ImageView imageView, Bitmap bitmap,            Object... params) {         if (imageView != null && bitmap != null) {            String url = (String) params[0];            if (url != null && url.equals((String) imageView.getTag())) {               ((ImageView) imageView).setImageBitmap(bitmap);            } else {               Log.e(TAG, "callback, bmp not match");            }         } else {            Log.e(TAG, "callback, bmp null");         }      }   };   public ImageBucketAdapter(Activity act, List<ImageBucket> list) {      this.act = act;      dataList = list;      cache = new BitmapCache();   }   @Override   public int getCount() {      // TODO Auto-generated method stub      int count = 0;      if (dataList != null) {         count = dataList.size();      }      return count;   }   @Override   public Object getItem(int arg0) {      // TODO Auto-generated method stub      return null;   }   @Override   public long getItemId(int arg0) {      // TODO Auto-generated method stub      return arg0;   }   class Holder {      private ImageView iv;      private ImageView selected;      private TextView name;      private TextView count;   }   @Override   public View getView(int arg0, View arg1, ViewGroup arg2) {      // TODO Auto-generated method stub      Holder holder;      if (arg1 == null) {         holder = new Holder();         arg1 = View.inflate(act, R.layout.friends_cricle_add_image_bucket, null);         holder.iv = (ImageView) arg1.findViewById(R.id.image);         holder.selected = (ImageView) arg1.findViewById(R.id.isselected);         holder.name = (TextView) arg1.findViewById(R.id.tvName);         holder.count = (TextView) arg1.findViewById(R.id.count);         arg1.setTag(holder);      } else {         holder = (Holder) arg1.getTag();      }      ImageBucket item = dataList.get(arg0);      holder.count.setText("" + item.count);      holder.name.setText(item.bucketName);      holder.selected.setVisibility(View.GONE);      if (item.imageList != null && item.imageList.size() > 0) {         String thumbPath = item.imageList.get(0).thumbnailPath;         String sourcePath = item.imageList.get(0).imagePath;         holder.iv.setTag(sourcePath);//       cache.displayBmp(holder.iv, thumbPath, sourcePath, callback);         cache.displayBmp(holder.iv, sourcePath, sourcePath, callback);      } else {         holder.iv.setImageBitmap(null);         Log.e(TAG, "no images in bucket " + item.bucketName);      }      return arg1;   }}

专辑帮助类/** * 专辑帮助类 *  * @author Administrator *  */public class AlbumHelper {   final String TAG = getClass().getSimpleName();   Context mContext;   ContentResolver mContentResolver;   // 缩略图列表   HashMap<String, String> mThumbnailList = new HashMap<String, String>();   // 专辑列表   List<HashMap<String, String>> mAlbumList = new ArrayList<HashMap<String, String>>();   HashMap<String, ImageBucket> mBucketList = new HashMap<String, ImageBucket>();   private static AlbumHelper instance;   private AlbumHelper() {   }   public static AlbumHelper getHelper() {      if (instance == null) {         instance = new AlbumHelper();      }      return instance;   }   /**    * 初始化    *     * @param context    */   public void init(Context context) {      if (this.mContext == null) {         this.mContext = context;         mContentResolver = context.getContentResolver();      }   }   /**    * 得到缩略图    */   private void getThumbnail() {      String[] projection = { Thumbnails._ID, Thumbnails.IMAGE_ID,Thumbnails.DATA };      Cursor cursor = mContentResolver.query(Thumbnails.EXTERNAL_CONTENT_URI, projection,null, null, null);      getThumbnailColumnData(cursor);   }   /**    * 从数据库中得到缩略图    *     * @param cur    */   private void getThumbnailColumnData(Cursor cur) {      if (cur.moveToFirst()) {         int _id;         int image_id;         String image_path;         int _idColumn = cur.getColumnIndex(Thumbnails._ID);         int image_idColumn = cur.getColumnIndex(Thumbnails.IMAGE_ID);         int dataColumn = cur.getColumnIndex(Thumbnails.DATA);         do {            // Get the field values            _id = cur.getInt(_idColumn);            image_id = cur.getInt(image_idColumn);            image_path = cur.getString(dataColumn);            mThumbnailList.put("" + image_id, image_path);         } while (cur.moveToNext());      }   }   /**    * 得到原图    */   void getAlbum() {      String[] projection = { Albums._ID, Albums.ALBUM, Albums.ALBUM_ART,Albums.ALBUM_KEY, Albums.ARTIST, Albums.NUMBER_OF_SONGS };      Cursor cursor = mContentResolver.query(Albums.EXTERNAL_CONTENT_URI, projection, null,null, null);      getAlbumColumnData(cursor);   }   /**    * 从本地数据库中得到原图    *     * @param cur    */   private void getAlbumColumnData(Cursor cur) {      if (cur.moveToFirst()) {         int _id;         String album;         String albumArt;         String albumKey;         String artist;         int numOfSongs;         int _idColumn = cur.getColumnIndex(Albums._ID);         int albumColumn = cur.getColumnIndex(Albums.ALBUM);         int albumArtColumn = cur.getColumnIndex(Albums.ALBUM_ART);         int albumKeyColumn = cur.getColumnIndex(Albums.ALBUM_KEY);         int artistColumn = cur.getColumnIndex(Albums.ARTIST);         int numOfSongsColumn = cur.getColumnIndex(Albums.NUMBER_OF_SONGS);         do {            // Get the field values            _id = cur.getInt(_idColumn);            album = cur.getString(albumColumn);            albumArt = cur.getString(albumArtColumn);            albumKey = cur.getString(albumKeyColumn);            artist = cur.getString(artistColumn);            numOfSongs = cur.getInt(numOfSongsColumn);            // Do something with the values.            Log.i(TAG, _id + " album:" + album + " albumArt:" + albumArt                  + "albumKey: " + albumKey + " artist: " + artist                  + " numOfSongs: " + numOfSongs + "---");            HashMap<String, String> hash = new HashMap<String, String>();            hash.put("_id", _id + "");            hash.put("album", album);            hash.put("albumArt", albumArt);            hash.put("albumKey", albumKey);            hash.put("artist", artist);            hash.put("numOfSongs", numOfSongs + "");            mAlbumList.add(hash);         } while (cur.moveToNext());      }   }   /**    * 是否创建了图片集    */   boolean hasBuildImagesBucketList = false;   /**    * 得到图片集    */   void buildImagesBucketList() {      mBucketList.clear();//清空以免重复加载      long startTime = System.currentTimeMillis();      // 构造缩略图索引      getThumbnail();      // 构造相册索引      String columns[] = new String[] { Media._ID, Media.BUCKET_ID,            Media.PICASA_ID, Media.DATA, Media.DISPLAY_NAME, Media.TITLE,            Media.SIZE, Media.BUCKET_DISPLAY_NAME };      // 得到一个游标      Cursor cur = mContentResolver.query(Media.EXTERNAL_CONTENT_URI, columns, null, null,            null);      if (cur.moveToFirst()) {         // 获取指定列的索引         int photoIDIndex = cur.getColumnIndexOrThrow(Media._ID);         int photoPathIndex = cur.getColumnIndexOrThrow(Media.DATA);         int photoNameIndex = cur.getColumnIndexOrThrow(Media.DISPLAY_NAME);         int photoTitleIndex = cur.getColumnIndexOrThrow(Media.TITLE);         int photoSizeIndex = cur.getColumnIndexOrThrow(Media.SIZE);         int bucketDisplayNameIndex = cur               .getColumnIndexOrThrow(Media.BUCKET_DISPLAY_NAME);         int bucketIdIndex = cur.getColumnIndexOrThrow(Media.BUCKET_ID);         int picasaIdIndex = cur.getColumnIndexOrThrow(Media.PICASA_ID);         // 获取图片总数         int totalNum = cur.getCount();         do {            String _id = cur.getString(photoIDIndex);            String name = cur.getString(photoNameIndex);            String path = cur.getString(photoPathIndex);            String title = cur.getString(photoTitleIndex);            String size = cur.getString(photoSizeIndex);            String bucketName = cur.getString(bucketDisplayNameIndex);            String bucketId = cur.getString(bucketIdIndex);            String picasaId = cur.getString(picasaIdIndex);            Log.i(TAG, _id + ", bucketId: " + bucketId + ", picasaId: "                  + picasaId + " name:" + name + " path:" + path                  + " title: " + title + " size: " + size + " bucket: "                  + bucketName + "---");            ImageBucket bucket = mBucketList.get(bucketId);            if (bucket == null) {               bucket = new ImageBucket();               mBucketList.put(bucketId, bucket);               bucket.imageList = new ArrayList<ImageItem>();               bucket.bucketName = bucketName;            }            bucket.count++;            ImageItem imageItem = new ImageItem();            imageItem.imageId = _id;            imageItem.imagePath = path;            imageItem.thumbnailPath = mThumbnailList.get(_id);            bucket.imageList.add(imageItem);         } while (cur.moveToNext());      }      Iterator<Entry<String, ImageBucket>> itr = mBucketList.entrySet().iterator();      while (itr.hasNext()) {         Entry<String, ImageBucket> entry = (Entry<String, ImageBucket>) itr.next();         ImageBucket bucket = entry.getValue();         Log.d(TAG, entry.getKey() + ", " + bucket.bucketName + ", "+ bucket.count + " ---------- ");         for (int i = 0; i < bucket.imageList.size(); ++i) {            ImageItem image = bucket.imageList.get(i);            Log.d(TAG, "----- " + image.imageId + ", " + image.imagePath+ ", " + image.thumbnailPath);         }      }      hasBuildImagesBucketList = true;      long endTime = System.currentTimeMillis();      Log.d(TAG, "use time: " + (endTime - startTime) + " ms");   }   /**    * 得到图片集    *     * @param refresh    * @return    */   public List<ImageBucket> getImagesBucketList(boolean refresh) {      if (refresh || (!refresh && !hasBuildImagesBucketList)) {         buildImagesBucketList();      }      List<ImageBucket> tmpList = new ArrayList<ImageBucket>();      Iterator<Entry<String, ImageBucket>> itr = mBucketList.entrySet().iterator();      while (itr.hasNext()) {         Entry<String, ImageBucket> entry = (Entry<String, ImageBucket>) itr.next();         tmpList.add(entry.getValue());      }      return tmpList;   }   /**    * 得到原始图像路径    *     * @param image_id    * @return    */   String getOriginalImagePath(String image_id) {      String path = null;      Log.i(TAG, "---(^o^)----" + image_id);      String[] projection = { Media._ID, Media.DATA };      Cursor cursor = mContentResolver.query(Media.EXTERNAL_CONTENT_URI, projection,Media._ID + "=" + image_id, null, null);      if (cursor != null) {         cursor.moveToFirst();         path = cursor.getString(cursor.getColumnIndex(Media.DATA));      }      return path;   }}

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