Android file cache and SD card creation directory failed to resolve and bitmap memory overflow resolved

1. Related code:

Join permissions:

<uses-permission android:name= "Android.permission.WRITE_EXTERNAL_STORAGE"/>    <uses-permission Android:name= "Android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>      /** get SD card path **/    private static String Getsdpath () {        String sdcardpath = null;        Boolean sdcardexist = Environment.getexternalstoragestate (). Equals (                Android.os.Environment.MEDIA_MOUNTED);  Infer if the SD card exists if        (sdcardexist) {            Sdcardpath = environment.getexternalstoragedirectory ();//Get root folder        }        if (Sdcardpath! = null) {            return sdcardpath;        } else {            return "";        }    }

Workaround: Obtain the code for the root folder instead:
Sdcardpath = Environment.getexternalstoragedirectory (). GetAbsolutePath ();

So that's it.

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Attached file Cache class:

Package Com.etnet.utilities;import Java.io.file;import Java.io.filenotfoundexception;import Java.io.fileoutputstream;import Java.io.ioexception;import Java.io.outputstream;import Java.util.Arrays;import Java.util.comparator;import Android.graphics.bitmap;import Android.graphics.bitmapfactory;import Android.os.environment;import android.os.statfs;import android.util.log;/** * picture file Save, read and write class * @author Barry */public class    Fileoperationutil {private static final String TAG = "Fileoperationutil";                                                                private static final String cache_directory = "Tqprocache";    private static final int MB = 1024*1024;    private static final int max_cache_size = ten * MB;        private static final int least_size_of_sdcard = ten * MB; /** get picture from cache **/public static Bitmap getImage (final string imageUrl) {final string path = Getcachedirectory       () + "/" + converturltofilename (IMAGEURL);    LOG.I (TAG, "GetImage filepath:" + path);   LOG.I (TAG, "GetImage URL:" + URL);        File File = new file (path);        if (file.exists ()) {//LOG.I (TAG, "GetImage file exists");        Bitmap bmp = null; try {//width becomes 1/3 of the original. High also becomes 1/3 of the original.         This is to reduce memory consumption, to prevent memory overflow bitmapfactory.options options=new bitmapfactory.options ();         Options.insamplesize = 3;        BMP = Bitmapfactory.decodefile (path,options); LOGUTIL.D (TAG, "BMP size=" +bmp.getbytecount ());}            catch (Exception e) {e.printstacktrace ();}            if (BMP = = null) {file.delete ();                } else {updatefiletime (path);            return BMP;    }} return null; /** the picture into the file cache **/public static void Savebitmap (St        Ring IMAGEURL, Bitmap BM) {if (BM = = null) {return; }//Infer space on SDcard if (Getfreespaceofsdcard () < Least_size_of_sdcard) {//SD space is low RetuRn        } String filename = Converturltofilename (IMAGEURL);        String dir = getcachedirectory ();        File Dirfile = new file (dir);        if (!dirfile.exists ()) {if (!dirfile.mkdirs ()) {LOG.W (TAG, "Create cache file Directorys failed");        }} File File = new file (dir + "/" + filename);            try {file.createnewfile ();            OutputStream OutStream = new FileOutputStream (file);            Bm.compress (Bitmap.CompressFormat.JPEG, OutStream);            Outstream.flush ();        Outstream.close ();        } catch (FileNotFoundException e) {LOG.W (TAG, "FileNotFoundException");        } catch (IOException e) {LOG.W (TAG, "IOException"); }}/** * Calculates the file size under the storage folder, * When the total file size is greater than the specified Max_ca         Che_size or sdcard the remaining space is less than the specified Least_size_of_sdcard * Then delete 40% files that have not been used recently */public static Boolean Removeextracache () { File DIR = new File (Getcachedirectory ());        file[] files = dir.listfiles ();        if (files = = null) {return true; } if (!android.os.environment.getexternalstoragestate (). Equals (Android.os.Environment.MEDIA_MOUNTED        ) {return false;        } int dirsize = 0;        for (int i = 0; i < files.length; i++) {dirsize + = Files[i].length ();                                                                    }//LOGUTIL.D ("Barry", "dirsize=" +dirsize); if (Dirsize > Max_cache_size | | getfreespaceofsdcard () < Least_size_of_sdcard) {int removenum = (int) ((            0.4 * files.length) + 1); /* Ascending order based on the last modified time of the file */arrays.sort (Files, new comparator<file> () {@Override Publ             IC int Compare (file file1, file file2) {if (file1.lastmodified () > File2.lastmodified ()) {            return 1;                     } else if (file1.lastmodified () = = File2.lastmodified ()) {return 0;                     } else {return-1;           }                 }}); /* for (int i = 0; i < files.length; i++) {LOGUTIL.D ("Barry", "File.modifiedtime=" +files[i].lastmodified ()) ;}            */for (int i = 0; i < Removenum; i++) {files[i].delete ();        } return true;        }else{return false; }}/** change the last modified time of the file **/public static void update        FileTime (String path) {File File = new file (path);        Long newmodifiedtime = System.currenttimemillis ();    File.setlastmodified (Newmodifiedtime); /** calculates the remaining space on the sdcard **/private static int getfrees Paceofsdcard () {StatFs stat = new StatFs (ENvironment.getexternalstoragedirectory (). GetPath ());        Double sdfreesize = (double) stat.getavailableblocks () * (double) stat.getblocksize ());    return (int) sdfreesize; } private static string Converturltofilename (string URL        ) {string[] STRs = Url.split ("/");        String savedimagename = strs[strs.length-1];    return savedimagename; /** Gets the cache folder **/private static String Getcachedire        Ctory () {String dir = getsdpath () + "/" + cache_directory;    return dir; }/** Gets the SD card path **/private static String Getsdpath ()        {String sdcardpath = null;  Boolean sdcardexist = Environment.getexternalstoragestate (). Equals (Android.os.Environment.MEDIA_MOUNTED); Infer if the SD card exists if (sdcardexist) {Sdcardpath = EnviROnment.getexternalstoragedirectory (). GetAbsolutePath ();        Gets the root folder} if (Sdcardpath! = null) {return sdcardpath;        } else {return ""; }    }}

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Android file cache and SD card creation directory failed to resolve and bitmap memory overflow resolved