Saving Image or other files in External Storage is a regular task for an Android Programmer.
Important Key Notes:
- Add the relevant permissions to your AndroidManifest.xml file:
<uses-permissionandroid:name="android.permission.WRITE_EXTERNAL_STORAGE"> - A different thread should be used, because saving image or any other file is a time consuming task. Otherwise you may get ANR error. Here, I have used Async Task.
At first check the external storage whether it is readable and writable
boolean mExternalStorageAvailable = false;
boolean mExternalStorageWriteable = false;
String state = Environment.getExternalStorageState();
if (Environment.MEDIA_MOUNTED.equals(state)) {
// Can read and write the media
mExternalStorageAvailable = mExternalStorageWriteable = true;
} else if (Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) {
// Can only read the media
mExternalStorageAvailable = true;
mExternalStorageWriteable = false;
} else {
// Can't read or write
mExternalStorageAvailable = mExternalStorageWriteable = false;
}
Log.i(TAG,"External Media: readable=" + mExternalStorageAvailable
+ " writable=" + mExternalStorageWriteable);
Write the image to disk in a random fashion
String root = Environment.getExternalStorageDirectory().toString();
File myDir = new File(root + "/com_mycompany_applicationname");
myDir.mkdirs();
Random generator = new Random();
int n = 10000;
n = generator.nextInt(n);
String fname = "Image-"+ n +".jpg";
File file = new File (myDir, fname);
if (file.exists ()) file.delete ();
try {
FileOutputStream out = new FileOutputStream(file);
out.flush();
out.close();
} catch (Exception e) {
e.printStackTrace();
}
The whole at a glance
private class SaveWallpaperAsyncTask extends AsyncTask<String, Void, String> {
@Override
protected String doInBackground(String... params) {
String URL = "path/of/remote/image";
Log.i("SaveWallpaperAsyncTask","SinglePageImageURL = "+URL);
checkExternalMedia();
saveWallpaper(URL);
return "Executed";
}
@Override
protected void onPostExecute(String result) {
}
@Override
protected void onPreExecute() {
}
@Override
protected void onProgressUpdate(Void... values) {
}
private void saveWallpaper(String urlString) {
Log.i("SaveWallpaperAsyncTask","Entered at saveWallpaper method");
String root = Environment.getExternalStorageDirectory().toString();
File myDir = new File(root + "/saved_images");
myDir.mkdirs();
Random generator = new Random();
int n = 10000;
n = generator.nextInt(n);
String fname = "Image-"+ n +".jpg";
File file = new File (myDir, fname);
if (file.exists ()) file.delete ();
try {
FileOutputStream out = new FileOutputStream(file);
out.flush();
out.close();
} catch (Exception e) {
e.printStackTrace();
}
}
private void checkExternalMedia() {
boolean mExternalStorageAvailable = false;
boolean mExternalStorageWriteable = false;
String state = Environment.getExternalStorageState();
if (Environment.MEDIA_MOUNTED.equals(state)) {
// Can read and write the media
mExternalStorageAvailable = mExternalStorageWriteable = true;
} else if (Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) {
// Can only read the media
mExternalStorageAvailable = true;
mExternalStorageWriteable = false;
} else {
// Can't read or write
mExternalStorageAvailable = mExternalStorageWriteable = false;
}
Log.i(TAG,"External Media: readable=" + mExternalStorageAvailable
+ " writable=" + mExternalStorageWriteable);
}
}
