Imageview display optimization, secondary cache, and soft reference ., Imageview second-level cache

Imageview display optimization, secondary cache, and soft reference ., Imageview second-level cache

Package com. app. util; import java. io. file; import java. io. fileOutputStream; import java. io. inputStream; import java.net. httpURLConnection; import java.net. URL; import java. util. hashMap; import java. util. map; import android. content. context; import android. graphics. bitmap; import android. graphics. bitmap. compressFormat; import android. graphics. bitmapFactory; import android. OS. asyncTask; import android. widget. image View;/*** asynchronously load the image and display the image (Bitmap) cache: 1. cache the bitmap object corresponding to the image in the memory (level-1 cache) 2. save the image to the mobile phone (second-level cache) 3. server Side */public class ImageLoader2 {private int defaultBitmapId; private Context context; // private Map of the set of cached image objects in memory <String, Bitmap> cache = new HashMap <String, bitmap> (); public ImageLoader2 (Context context, int defaultBitmapId) {this. defaultBitmapId = defaultBitmapId; this. context = context;}/*** load the Image Based on the image path and display the image * @ param Imagepath * @ param imageView */public void loadImage (String imagepath, ImageView imageView) {// Save the imageView tag. setTag (imagepath); // obtain the bitmap object Bitmap bitmap = getFromFirstCache (imagepath) from the first-level cache; if (bitmap! = Null) {// If yes, the imageView is displayed directly. setImageBitmap (bitmap); return;} // obtain the bitmap object bitmap = getFromSecondCache (imagepath) from the second-level cache; if (bitmap! = Null) {// If yes, the imageView is displayed directly. setImageBitmap (bitmap); return;} // obtain from the server // display the default image imageView. setImageResource (R. drawable. shop_photo_frame); loadImageFromNet (imagepath, imageView);}/*** get an image from the server, and displays * @ param imagepath * @ param imageView */private void loadImageFromNet (final String imagepath, final ImageView imageView) {new AsyncTask <Void, Void, Bitmap> () {@ Overrideprotected Bitmap doInBackground (Void ... Params) {String newPath = (String) imageView. getTag (); if (newPath! = Imagepath) // if they are different, the imageView has been reused. You do not need to load the server-side image return null; Bitmap bitmap = null; try {URL url = new URL (imagepath ); httpURLConnection connection = (HttpURLConnection) url. openConnection (); connection. setDoInput (true); connection. setConnectTimeout (5000); connection. setReadTimeout (5000); connection. connect (); if (connection. getResponseCode () == 200) {InputStream is = connection. getInputStream (); // bitmap of the image stream = BitmapFactory. decodeStream (is); if (bitmap! = Null) {// cache to a level-1 cache. put (imagepath, bitmap); // cached to the second-level cache. Save bitmap as an image String filename = imagepath. substring (imagepath. lastIndexOf ("/") + 1); File cacheFile = context. getCacheDir (); bitmap. compress (CompressFormat. JPEG, 100, new FileOutputStream (new File (cacheFile, filename) ;}} catch (Exception e) {e. printStackTrace ();} return bitmap;} @ Overrideprotected void onPostExecute (Bitmap bitmap) {String newPa Th = (String) imageView. getTag (); if (bitmap! = Null & newPath = imagepath) {// imageview.setimagebitmap(bitmap;}}}cmd.exe cute ();}/*** obtain the bitmap object from the second-level cache * the image is cached: /data/packagename/cache/* @ param imagepath: http ://... /f1.jpg * @ return */private Bitmap getFromSecondCache (String imagepath) {// obtain the image's local path String filename = imagepath. substring (imagepath. lastIndexOf ("/") + 1); File cacheFile = context. getCacheDir (); String filePath = cacheFile. getAbsolutePath () + "/" + filename; // data/packagename/cache/f1.jpg // load the image file to obtain the bitmap object Bitmap bitmap = BitmapFactory. decodeFile (filePath); return bitmap;}/*** obtain the bitmap object from the first-level cache * @ param imagepath * @ return */private Bitmap getFromFirstCache (String imagepath) {Bitmap bitmap = cache. get (imagepath); return bitmap ;}}