Develop Reference

Downloading a Very Large file silently dies

So I'm trying to download a very large file through Retrofit2. Files can range up to 5-10 GB. I'm launching an asynchronous structure from an activity/fragment (I've tried both AsyncTask and IntentService) and streaming the file and writing the bytes to a file on the internal storage. I'm publishing progress of the filewrite after each buffer read.
Files up to 150 MB or so work fine, but when I try a 5 GB file the stream silently dies after about 1 GB. There are no logs or logcat that I can see, no exceptions are thrown just poof.
Does anyone have an idea on what's happening, or perhaps I wrote something wrong?
public interface IFileshareDownload {
#Streaming
#GET("File/Download/{guid}")
Call<ResponseBody> downloadFileByGuid(#Path("guid") String guid);
}
public class FileshareDownloadService extends IntentService {
private static final String TAG = "[FileDownloadService]";
private static final String PATH = "/ftp/";
private static final int FILE_CHUNK_SIZE = 2 * 1024 * 1024; //2MB buffer
private String mFilename;
private String mFileshareDirectory;
private String mAbsoluteFilePath;
private String mBaseUrl;
private String mGuid;
private Long mFileSize;
private Retrofit mRetrofit;
private IFileshareDownload mDownloader;
private ResultReceiver mReceiver;
public FileshareDownloadService() {
super("FileshareDownload");
}
#Override
protected void onHandleIntent(#Nullable Intent intent) {
this.mBaseUrl = intent.getStringExtra("baseUrl");
this.mGuid = intent.getStringExtra("guid");
this.mFilename = intent.getStringExtra("fileName");
this.mFileSize = intent.getLongExtra("fileSize", -1);
this.mFileshareDirectory = getApplicationContext().getFilesDir().getAbsolutePath() + PATH;
this.mAbsoluteFilePath = mFileshareDirectory + mFilename;
this.mRetrofit = new Retrofit.Builder()
.baseUrl(mBaseUrl)
.callbackExecutor(Executors.newSingleThreadExecutor())
.build();
this.mDownloader = mRetrofit.create(IFileshareDownload.class);
this.mReceiver = intent.getParcelableExtra("listener");
downloadFile();
}
public void downloadFile() {
Call<ResponseBody> call = mDownloader.downloadFileByGuid(mGuid);
try {
Response<ResponseBody> response = call.execute();
if(response.isSuccessful()) {
File file = new File(mAbsoluteFilePath);
file.createNewFile();
try(FileOutputStream fos = new FileOutputStream(file)) {
InputStream is = response.body().byteStream();
setUpdateProgress(SHOW_PROGRESS);
int count = 0;
long bytesRead = 0;
byte[] buffer = new byte[FILE_CHUNK_SIZE];
try {
while ((count = is.read(buffer)) != -1) {
fos.write(buffer, 0, count);
fos.flush();
bytesRead += count;
int progress = getPercent(bytesRead, mFileSize);
Log.d(TAG, String.format("Read %d out of %d bytes.", bytesRead, mFileSize));
setUpdateProgress(UPDATE_PROGRESS, progress);
}
} catch (Throwable t)
{
Log.e(TAG, "What happened?", t);
}
}
setUpdateProgress(HIDE_PROGRESS);
} else {
setUpdateProgress(HIDE_PROGRESS);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}

Here is a great tutorial about downloading files. It probably mentions what you need:
https://futurestud.io/tutorials/retrofit-2-how-to-download-files-from-server
If it doesn't, take a look at the #Multipart annotation, as well as #Part. I'm not sure if you can use it with GET, but since you have no answers yet, I'll just post it here so you can take the shot if you want.
This is an example from a project I had, in which we create a multipart body to upload an image. I know you want a GET, but the example should still be relevant:
// Setting up the multipart file
File newAvatar = new File(getRealPathFromURI(avatarUri)); // the new avatar
RequestBody filePart = RequestBody.create(MediaType.parse(getActivity().getContentResolver().getType(avatarUri)), newAvatar);
And your request (a POST in this example) should be something like this:
#Multipart
#POST("/api/v1/me/account/upload-cover") // upload avatar
Call<ResponseChangeAvatar> sendChangeAvatarRequest(#Part MultipartBody.Part file, #Header("Authorization") String token);
The retrofit documentation (just search for multipart):
http://square.github.io/retrofit/
A tutorial, in which he creates a multipart body to upload a file to a server:
https://futurestud.io/tutorials/retrofit-2-how-to-upload-files-to-server
Hope this helps. Let me know if you found the solution.

Android : java.lang.OutOfMemoryError: Failed to allocate with free bytes and 70MB until OOM when using gson.toJson()

In my Android application I am getting below exception when I try to sync my data to the server which is large in size. I get this exception when data size is more than 20 MB I think. I am saving bitmap images as string using base64 encoding after sacle down the image size which makes such huge data.
04-18 13:51:51.957 16199-16816/com.example.myproject.app E/art﹕ Throwing OutOfMemoryError "Failed to allocate a 128887990 byte allocation with 16777216 free bytes and 70MB until OOM"
04-18 13:51:52.037 16199-16816/com.example.myproject.app E/AndroidRuntime﹕ FATAL EXCEPTION: Thread-4482
Process: com.example.myproject.app, PID: 16199
java.lang.OutOfMemoryError: Failed to allocate a 128887990 byte allocation with 16777216 free bytes and 70MB until OOM
at java.lang.AbstractStringBuilder.enlargeBuffer(AbstractStringBuilder.java:95)
at java.lang.AbstractStringBuilder.append0(AbstractStringBuilder.java:146)
at java.lang.StringBuffer.append(StringBuffer.java:219)
at java.io.StringWriter.write(StringWriter.java:167)
at com.google.gson.stream.JsonWriter.string(JsonWriter.java:570)
at com.google.gson.stream.JsonWriter.value(JsonWriter.java:419)
at com.google.gson.internal.bind.TypeAdapters$16.write(TypeAdapters.java:426)
at com.google.gson.internal.bind.TypeAdapters$16.write(TypeAdapters.java:410)
at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:68)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.write(ReflectiveTypeAdapterFactory.java:112)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.write(ReflectiveTypeAdapterFactory.java:239)
at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:68)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:97)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:61)
at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:68)
How to solve this problem? I know that this comes when I convert the data from class to json using Gson. Below is my code:
SimpleDateFormat dtf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss",Locale.ENGLISH);
GsonBuilder builder = new GsonBuilder();
builder.registerTypeAdapter(Date.class, new JsonDeserializer<Date>() {
#Override
public Date deserialize(JsonElement json, Type type, JsonDeserializationContext deserializationContext) throws JsonParseException {
String frStr = json.getAsJsonPrimitive().getAsString();
Date retDate =null;
try {
retDate = dtf.parse(frStr);
} catch (ParseException e) {
e.printStackTrace();
}
return retDate;
}
});
builder.registerTypeAdapter(Date.class, new JsonSerializer<Date>() {
#Override
public JsonElement serialize(Date src, Type typeOfSrc, JsonSerializationContext context) {
String jsDate = dtf.format(src);
return new JsonPrimitive(jsDate);
}
});
builder.registerTypeAdapter(byte[].class, new JsonDeserializer<byte[]>() {
#Override
public byte[] deserialize(JsonElement json, Type type, JsonDeserializationContext deserializationContext) throws JsonParseException {
return Base64.decode(json.getAsString(), Base64.NO_WRAP);
}
});
gson = builder.create();
attDataAcc.setAttList(attList);
String jsonAttAccts = gson.toJson(attDataAcc, AttachmentDataList.class);
HttpEntity<String> entityAtt = new HttpEntity<String>(jsonAttAccts,headers);
ResponseEntity<String> restResA = restTemplate.exchange(strUrl+"/saveAttToServer", HttpMethod.POST, entityAtt, String.class);
public class Attachment implements Serializable {
#DatabaseField(columnName = "id",id = true)
private String id;
#DatabaseField(columnName = "user_id")
private Integer userId;
#DatabaseField(columnName = "attachment_id")
private String attachmentId;
#DatabaseField(columnName = "file_name")
private String fileName;
#DatabaseField(columnName = "file_data")
private String fileData;
#DatabaseField(columnName = "date",dataType=DataType.DATE)
private Date date;
public Attachment() {
super();
// TODO Auto-generated constructor stub
}
public Attachment(String id, Integer userId, String attachmentId, String fileName, String fileData, Date date) {
this.id = id;
this.userId = userId;
this.attachmentId = attachmentId;
this.fileName = fileName;
this.fileData = fileData;
this.date = date;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public Integer getUserId() {
return userId;
}
public void setUserId(Integer userId) {
this.userId = userId;
}
public String getAttachmentId() {
return attachmentId;
}
public void setAttachmentId(String attachmentId) {
this.attachmentId = attachmentId;
}
public String getFileName() {
return fileName;
}
public void setFileName(String fileName) {
this.fileName = fileName;
}
public String getFileData() {
return fileData;
}
public void setFileData(String fileData) {
this.fileData = fileData;
}
public Date getDate() {
return date;
}
public void setDate(Date date) {
this.date = date;
}
#Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Attachment that = (Attachment) o;
if (id != null ? !id.equals(that.id) : that.id != null) return false;
if (userId != null ? !userId.equals(that.userId) : that.userId != null) return false;
if (attachmentId != null ? !attachmentId.equals(that.attachmentId) : that.attachmentId != null) return false;
if (fileName != null ? !fileName.equals(that.fileName) : that.fileName != null) return false;
if (fileData != null ? !fileData.equals(that.fileData) : that.fileData != null) return false;
if (date != null ? !date.equals(that.date) : that.date != null) return false;
}
#Override
public int hashCode() {
int result = id != null ? id.hashCode() : 0;
result = 31 * result + (userId != null ? userId.hashCode() : 0);
result = 31 * result + (attachmentId != null ? attachmentId.hashCode() : 0);
result = 31 * result + (fileName != null ? fileName.hashCode() : 0);
result = 31 * result + (fileData != null ? fileData.hashCode() : 0);
result = 31 * result + (date != null ? date.hashCode() : 0);
return result;
}
#Override
public String toString() {
return userFileName;
}
}
public class AttachmentDataList implements Serializable {
private ArrayList<Attachment> attList;
public ArrayList<Attachment> getAttList() {
return attList;
}
public void setAttList(ArrayList<Attachment> attList) {
this.attList = attList;
}
}

You're running into OutOfMemoryError because you're using inefficient and very memory-consuming Base64 transformations. Another hit here is Gson: it does not provide any raw-write methods for JsonWriter and JsonReader classes: the most you can do here is writing/reading a single string value. Collecting a huge input to a single string is another very memory-consuming operation: check your stacktrace to make sure that a string builder instance is used under the very hood -- and this is just to write a single value to the output stream. In short, it all looks like this (if I'm not mistaken about your code, because it seems to lack really important parts, so I'm just trying to reconstruct your scenario):
Obtaining a byte array (that would be a new object, probably a clone of another byte array);
Converting the byte array to a Base64 encoded string (it also hits performance because the would clone the byte array to create a defensive copy);
Converting ALL to a String gson.toJson(attDataAcc, AttachmentDataList.class); -- another huge hit.
All of this is extremely memory consuming. And it would be nice if Gson could support raw write to the output stream, but currently it lacks any of it.
In theory, you might overcome this issue by just writing to the underlying streams (probably directly from your byte array source without any massive transformations because Base64 can be streamed as well thus consuming memory minimum). You mentioned Gson 2.6.2, but I'm working with Gson 2.8.0, so the below solution can 100% work with Gson 2.8.0 only, and may not work even for any other minor Gson versions because it uses reflection in order to "hack" the JsonWriter class.
final class ByteArrayTypeAdapter
extends TypeAdapter<byte[]> {
// These two methods and one field from the super class privates are necessary to make it all work
private static final Method writeDeferredNameMethod;
private static final Method beforeValueMethod;
private static final Field writerField;
static {
try {
writeDeferredNameMethod = JsonWriter.class.getDeclaredMethod("writeDeferredName");
writeDeferredNameMethod.setAccessible(true);
beforeValueMethod = JsonWriter.class.getDeclaredMethod("beforeValue");
beforeValueMethod.setAccessible(true);
writerField = JsonWriter.class.getDeclaredField("out");
writerField.setAccessible(true);
} catch ( final NoSuchMethodException | NoSuchFieldException ex ) {
throw new RuntimeException(ex);
}
}
// This type adapter is effectively a singleton having no any internal state
private static final TypeAdapter<byte[]> byteArrayTypeAdapter = new ByteArrayTypeAdapter();
private ByteArrayTypeAdapter() {
}
// But making the constructor private and providing access to the instance via the method, we make sure that the only instance exists and it's safe
static TypeAdapter<byte[]> getByteArrayTypeAdapter() {
return byteArrayTypeAdapter;
}
#Override
public void write(final JsonWriter out, final byte[] bytes)
throws IOException {
try {
// Since we're writing a byte[] array, that's probably a field value, make sure that the corresponding property name has been written to the output stream
writeDeferredNameAndFlush(out);
// Now simulate JsonWriter.value(byte[]) if such a method could exist
writeRawBase64ValueAndFlush(bytes, (Writer) writerField.get(out));
} catch ( IllegalAccessException | InvocationTargetException ex ) {
throw new IOException(ex);
}
}
#Override
public byte[] read(final JsonReader in) {
// If necessary, requires more hacks...
// And this is crucial for the server-side:
// In theory, the client can generate HUGE Base64 strings,
// So the server could crash with OutOfMemoryError too
throw new UnsupportedOperationException();
}
private static void writeDeferredNameAndFlush(final Flushable out)
throws IOException, IllegalAccessException, InvocationTargetException {
writeDeferredNameMethod.invoke(out);
beforeValueMethod.invoke(out);
// Flush is necessary: the JsonWriter does not know that we're using its private field intruding to its privates and may not flush
out.flush();
}
private static void writeRawBase64ValueAndFlush(final byte[] bytes, final Writer writer)
throws IOException {
// Writing leading "
writer.write('\"');
// This comes from Google Guava
final BaseEncoding baseEncoding = BaseEncoding.base64();
final OutputStream outputStream = baseEncoding.encodingStream(writer);
// This too
// Note that we just r_e_d_i_r_e_c_t streams on fly not making heavy transformations
ByteStreams.copy(new ByteArrayInputStream(bytes), outputStream);
// This is necessary too
outputStream.close();
// Writing trailing "
writer.write('\"');
// Flush again to keep it all in sync
writer.flush();
}
}
I know it's a hack, but it's better than just getting OutOfMemoryError constantly.
Now, just make it work with Spring RestTemplates:
// Gson is thread-safe and can be re-used
private static final Gson gson = new GsonBuilder()
// SimpleDateFormat may be NOT thread-safe so you should not share the single SimpleDateFormat between threads
// However Gson supports date/time formats out of box
.setDateFormat("yyyy-MM-dd HH:mm:ss")
// Registering byte[] to the type adapter
.registerTypeAdapter(byte[].class, getByteArrayTypeAdapter())
.create();
private static final RestTemplate restTemplate = new RestTemplate();
private static final String URL = "http://localhost";
public static void main(final String... args) {
sendPostRequest("hello world".getBytes(), byte[].class);
}
private static void sendPostRequest(final Object object, final Type type) {
// This is where we're binding the output stream I was asking in the question comments
final RequestCallback requestCallback = request -> gson.toJson(object, type, new OutputStreamWriter(request.getBody()));
// Spring RestTemplates stuff here...
final SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();
requestFactory.setBufferRequestBody(false);
final ResponseExtractor<String> responseExtractor = new HttpMessageConverterExtractor<>(String.class, restTemplate.getMessageConverters());
restTemplate.setRequestFactory(requestFactory);
// Let it fly
restTemplate.execute(URL, POST, requestCallback, responseExtractor);
}
Note that you might write a specialized type adapter for special types that could write directly to output stream so you could not get rid of byte[] at all. You could also vote up for this issue at the official Gson issue tracker: https://github.com/google/gson/issues/971 and probably there could no any need in using any Java Reflection API hacks in a future version of Gson.

Create downloadable custom theme and apply it during run time

I'm making an Android app that needs to allow client to maintain the resources from their server which would include strings, drawables etc.
I've already created a mechanism for downloading a zip file with all these files, and they're able to change strings pretty easy, I've also created a mechanism that allows the client to change bg color for UI controls, to change width, height etc but I have a feeling that there must be a better way to create all this.
So I believe the real question is:
What's the best practice to create a custom theme, deploy it on server, make the app download it, and apply it to app afterwards?
I know how to create custom theme and how to deploy it with the app, and how to apply it during runtime, but the problem here is that resources are pre-compiled and once you create APK there's no way for developer to change them which would be required in order to add new themes/drawables/styles/strings.
Do I need to create a custom mechanism for all this (loading images, styles, strings etc from the file system) and to apply them during runtime by creating my own controls that would do that in constructor for example or is there a way to do this properly :)? ( how does Swiftkey do this with all the keyboard themes, and how do similar apps do it allowing the users to download theme and apply it after that )?
I'm sorry if I didn't see similar question, I really tried to find an answer myself during past 2 days, but I failed to find anything useful, so this is my last chance to get a constructive answer :).
The closest to solution i need was this answer: Changing app theme at runtime using using external theme file but I've already made that functionality, and i know i can change colors like that, but the problem is that i would like to be able to change things like borders, on button pressed state etc that require resources other than simple color value :(.
Thanks heaps!
P.S. I've also read about the extension files so is that something i need to consider while thinking about this, or do i need to look elsewhere? The problem with obb files is that they must be deployed over PlayStore and that's not "perfect" for the client because they need to pack it by using jobb, and to deploy it to PlayStore which is too technical for them, so they would prefer creating a zip file, putting it on server, and the app should do the rest :).

I've finally decided to solve this by making a custom system for handling drawables, strings etc so now i have a custom class called "ResourceManager" that handles what needs to be loadad and how, and themes are distributed as a zip file which app downloads, extracts and later uses.
I had to compile nine patch images by myself before putting them in zip file, and I did that using "abrc" from here: http://forum.xda-developers.com/showthread.php?t=785012
I've also created a simple bash script that goes recursively through custom folder and compiles all nine patch images with abrc.
I've also created a simple helper in the ResourceManager that checks and tells me the screen density so i can normally support images in hdpi, xhdpi etc densities, and finally i don't re-create the images every time i need them, i save them in a static list of HashMap so i can reuse the ones I've already created and that way i hope to prevent wasting too much phone's memory :).
OK that's all in short lines, if anyone has any questions please let me know, i'll be glad to share this experience with anyone.
Cheers!
============ EDIT ============
Here's the class I ended up writing for this purpose (it downloads the file, checks for it's version, loads strings from JSON file rather than strings.xml etc)
NOTE: This is not a full class so some parts are missing, but I think it's more than enough to get the idea how I solved all this :)
/**
* Created by bojank on 7/28/2014.
* Class that handles custom resources downloaded from server
*/
public class ResourceManager {
// List of ninePatchImages in the application
private static ArrayList<HashMap<String, NinePatchDrawable>> ninePatchHashMaps;
private static ArrayList<HashMap<String, Drawable>> imagesHashMaps;
private static ImageLoader imageLoader;
// Context for methods
public static Context ctx;
// JSONObject with all strings
private static JSONObject joString;
// JSONObject with all styles
private static JSONObject joStyles;
// String with current active lang code
private static String currentLanguage;
private static String sdcardPath;
// Private consturctor to prevent creating a class instance
private ResourceManager() {
}
/**
* Method that returns a translated string for given key
*
* #param key String
* #return String
*/
public static String getString(String module, String key) {
String output = ""; //String.format("[%s - %s]", module, key);
try {
if (getStringsFile() != null && getStringsFile().getJSONObject(module).has(key))
output = getStringsFile().getJSONObject(module).getString(key);
} catch (Exception e) {
// Force some default language if proper json file is missing for newly added language
currentLanguage = "en-US";
Helper.saveLocale(currentLanguage, ctx);
Helper.logError("ErrorFetchingString", e);
}
return output;
}
/**
* Method that returns JSONObject with string resources
* #return JSONObject
* #throws JSONException
*/
public static JSONObject getStringsFile() throws JSONException {
if (joString == null) {
String stringFileName = getResourcesPath() + "languages/" + getCurrentLanguage() + "/values.json";
String languageFile = Helper.readJsonFile(stringFileName);
if (languageFile != null) {
joString = new JSONObject(Helper.readJsonFile(stringFileName));
} else {
return null;
}
}
return joString.getJSONObject("strings");
}
/**
* Method that returns current language ("sr", "en"...)
* #return String
*/
public static String getCurrentLanguage() {
if (currentLanguage == null)
currentLanguage = Helper.getCurrentLanguage(ctx);
return currentLanguage;
}
/**
* Method that resets joString object and currentLanguage on language change
*/
public static void resetLanguage() {
joString = null;
currentLanguage = null;
}
/**
* Method that resets joStyles object on theme change
*/
public static void resetStyle() {
joStyles = null;
}
/**
* Method that deletes a directory from filesystem
* #param path File
* #return boolean
*/
public static boolean deleteDirectory(File path) {
if( path.exists() ) {
File[] files = path.listFiles();
for(int i=0; i<files.length; i++) {
if(files[i].isDirectory()) {
deleteDirectory(files[i]);
}
else {
files[i].delete();
}
}
}
return(path.delete());
}
/**
* Method that get's the version of assets file
* #param url String
*/
public static String getAssetsVersion(String url) throws IOException {
Helper.logInfo("REQUEST URL:", url);
OkHttpClient client = new OkHttpClient();
// set connection timeut to 5min
client.setConnectTimeout(1, TimeUnit.MINUTES);
Request request = new Request.Builder()
.url(url)
.build();
Response response = client.newCall(request).execute();
return response.body().string();
}
/**
* Method that downloads assets file from server
* #param url String
* #return String
* #throws IOException
*/
public static String getAssetsFile(String url) throws IOException {
Helper.logInfo("REQUEST URL:", url);
OkHttpClient client = new OkHttpClient();
// set connection timeut to 5min
client.setConnectTimeout(1, TimeUnit.MINUTES);
Request request = new Request.Builder()
.url(url)
.header("User-Agent", MyApplication.USER_AGENT)
.build();
Response response = client.newCall(request).execute();
InputStream inputStreamFile = response.body().byteStream();
try {
// Output stream
String outputFileName = Environment.getExternalStorageDirectory().toString() + "/assets.zip";
File deleteFile = new File(outputFileName);
deleteFile.delete();
OutputStream output = new FileOutputStream(outputFileName);
byte data[] = new byte[1024];
int count;
// writing data to file
while ((count = inputStreamFile.read(data)) != -1)
output.write(data, 0, count);
// flushing output
output.flush();
// closing streams
output.close();
inputStreamFile.close();
return outputFileName;
} catch (Exception e) {
Helper.logError("Download Resursa", e);
return "ERROR";
}
}
public static void setStyle(View v, String styleName) {
try {
if (styleName == null || styleName.equals("")) {
if (v instanceof EditText)
processStyle(v, getStylesFile().getJSONObject("EditText"));
} else
processStyle(v, getStylesFile().getJSONObject(styleName));
} catch (Exception e) {
Helper.logError("Setting Styles", e);
}
}
private static void setBackground(View v, Drawable d) {
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {
v.setBackgroundDrawable(d);
} else {
v.setBackground(d);
}
}
public static JSONObject getStylesFile() throws JSONException {
if (joStyles == null) {
String stylesFileName = getResourcesPath() + "styles/properties.json";
joStyles = new JSONObject(Helper.readJsonFile(stylesFileName));
}
return joStyles;
}
public static void processStyle(View v, JSONObject joStyle) {
if(joStyle != null) {
try {
// used for layout margins
LinearLayout.LayoutParams layoutParams = null;
if (Helper.isValidParameter(joStyle, "backgroundColor"))
v.setBackgroundColor(Color.parseColor(joStyle.getString("backgroundColor")));
if (Helper.isValidParameter(joStyle, "backgroundImage"))
setBackground(v, loadNinePatchFromFilesystem(getImagesPath() + joStyle.getString("backgroundImage")));
if (v instanceof TextView) {
applyTextViewParameters(v, joStyle);
} else if (v instanceof ListView) {
if (Helper.isValidParameter(joStyle, "dividerColor")) {
((ListView) v).setDivider(new ColorDrawable(Color.parseColor(joStyle.getString("dividerColor"))));
((ListView) v).setDividerHeight(Helper.convertDpToPixel(1));
}
if (Helper.isValidParameter(joStyle, "dividerHeight")) {
((ListView) v).setDividerHeight(Helper.convertDpToPixel(joStyle.getInt("dividerHeight")));
}
} else if (v instanceof UnderlinePageIndicator) {
if (Helper.isValidParameter(joStyle, "backgroundColor")) {
v.setBackgroundColor(Color.parseColor(joStyle.getString("backgroundColor")));
}
if (Helper.isValidParameter(joStyle, "selectedColor")) {
((UnderlinePageIndicator) v).setSelectedColor(Color.parseColor(joStyle.getString("selectedColor")));
}
} else if (v instanceof StyleableBackground) {
if (Helper.isValidParameter(joStyle, "backgroundColor")) {
View background = v.findViewById(R.id.llBackground);
if (background != null) {
background.setBackgroundColor(Color.parseColor(joStyle.getString("backgroundColor")));
}
}
if (Helper.isValidParameter(joStyle, "borderTopColor")) {
View topBorder = v.findViewById(R.id.llTopBorder);
if (topBorder != null) {
topBorder.setBackgroundColor(Color.parseColor(joStyle.getString("borderTopColor")));
if (Helper.isValidParameter(joStyle, "borderTopHeight")) {
topBorder.setMinimumHeight(Helper.convertDpToPixel(joStyle.getInt("borderTopHeight")));
}
}
}
if (Helper.isValidParameter(joStyle, "borderBottomColor")) {
View bottomBorder = v.findViewById(R.id.llBottomBorder);
if (bottomBorder != null) {
bottomBorder.setBackgroundColor(Color.parseColor(joStyle.getString("borderBottomColor")));
if (Helper.isValidParameter(joStyle, "borderBottomHeight")) {
bottomBorder.setMinimumHeight(Helper.convertDpToPixel(joStyle.getInt("borderBottomHeight")));
}
}
}
if (Helper.isValidParameter(joStyle, "backgroundImage")) {
ImageView ivBackgroundImage = (ImageView) v.findViewById(R.id.ivBackgroundImage);
if (ivBackgroundImage != null) {
BitmapDrawable d = (BitmapDrawable) ResourceManager.loadImageFromFilesystem(ResourceManager.getImagesPath() + joStyle.getString("backgroundImage"));
d.setTileModeXY(Shader.TileMode.REPEAT, Shader.TileMode.REPEAT);
d.setGravity(Gravity.FILL_HORIZONTAL | Gravity.FILL_VERTICAL);
setBackground(ivBackgroundImage, d);
}
}
}
if(Helper.isValidParameter(joStyle, "width"))
v.setMinimumWidth(joStyle.getInt("width"));
if(Helper.isValidParameter(joStyle, "height"))
v.setMinimumHeight(joStyle.getInt("height"));
if(Helper.isValidParameter(joStyle, "padding"))
v.setPadding(joStyle.getInt("padding"), joStyle.getInt("padding"), joStyle.getInt("padding"), joStyle.getInt("padding"));
if(Helper.isValidParameter(joStyle, "paddingLeft"))
v.setPadding(joStyle.getInt("paddingLeft"), v.getPaddingTop(), v.getPaddingRight(), v.getPaddingBottom());
if(Helper.isValidParameter(joStyle, "paddingTop"))
v.setPadding(v.getPaddingLeft(), joStyle.getInt("paddingTop"), v.getPaddingRight(), v.getPaddingBottom());
if(Helper.isValidParameter(joStyle, "paddingRight"))
v.setPadding(v.getPaddingLeft(), v.getPaddingTop(), joStyle.getInt("paddingRight"), v.getPaddingBottom());
if(Helper.isValidParameter(joStyle, "paddingBottom"))
v.setPadding(v.getPaddingLeft(), v.getPaddingTop(), v.getPaddingRight(), joStyle.getInt("paddingBottom"));
if(Helper.isValidParameter(joStyle, "margin")) {
layoutParams = new LinearLayout.LayoutParams(v.getLayoutParams());
layoutParams.setMargins(joStyle.getInt("margin"), joStyle.getInt("margin"), joStyle.getInt("margin"), joStyle.getInt("margin"));
}
if(Helper.isValidParameter(joStyle, "marginLeft")) {
layoutParams = new LinearLayout.LayoutParams(v.getLayoutParams());
layoutParams.setMargins(joStyle.getInt("marginLeft"), layoutParams.topMargin, layoutParams.rightMargin, layoutParams.bottomMargin);
}
if(Helper.isValidParameter(joStyle, "marginTop")) {
layoutParams = new LinearLayout.LayoutParams(v.getLayoutParams());
layoutParams.setMargins(layoutParams.leftMargin, joStyle.getInt("marginTop"), layoutParams.rightMargin, layoutParams.bottomMargin);
}
if(Helper.isValidParameter(joStyle, "marginRight")) {
layoutParams = new LinearLayout.LayoutParams(v.getLayoutParams());
layoutParams.setMargins(layoutParams.leftMargin, layoutParams.topMargin, joStyle.getInt("marginRight"), layoutParams.bottomMargin);
}
if(layoutParams != null)
v.setLayoutParams(layoutParams);
RelativeLayout.LayoutParams relativeLayoutParams = null;
if (Helper.isValidParameter(joStyle, "alignParentTop") && joStyle.getBoolean("alignParentTop")) {
relativeLayoutParams = new RelativeLayout.LayoutParams(v.getLayoutParams());
relativeLayoutParams.addRule(RelativeLayout.ALIGN_PARENT_TOP);
}
if (Helper.isValidParameter(joStyle, "alignParentLeft") && joStyle.getBoolean("alignParentLeft")) {
relativeLayoutParams = new RelativeLayout.LayoutParams(v.getLayoutParams());
relativeLayoutParams.addRule(RelativeLayout.ALIGN_PARENT_LEFT);
}
if (Helper.isValidParameter(joStyle, "alignParentBottom") && joStyle.getBoolean("alignParentBottom")) {
relativeLayoutParams = new RelativeLayout.LayoutParams(v.getLayoutParams());
relativeLayoutParams.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM);
}
if (Helper.isValidParameter(joStyle, "alignParentRight") && joStyle.getBoolean("alignParentRight")) {
relativeLayoutParams = new RelativeLayout.LayoutParams(v.getLayoutParams());
relativeLayoutParams.addRule(RelativeLayout.ALIGN_PARENT_RIGHT);
}
if(Helper.isValidParameter(joStyle, "marginLeft")) {
relativeLayoutParams = new RelativeLayout.LayoutParams(v.getLayoutParams());
relativeLayoutParams.setMargins(joStyle.getInt("marginLeft"), relativeLayoutParams.topMargin, relativeLayoutParams.rightMargin, relativeLayoutParams.bottomMargin);
}
if(Helper.isValidParameter(joStyle, "marginTop")) {
relativeLayoutParams = new RelativeLayout.LayoutParams(v.getLayoutParams());
relativeLayoutParams.setMargins(relativeLayoutParams.leftMargin, joStyle.getInt("marginTop"), relativeLayoutParams.rightMargin, relativeLayoutParams.bottomMargin);
}
if(Helper.isValidParameter(joStyle, "marginRight")) {
relativeLayoutParams = new RelativeLayout.LayoutParams(v.getLayoutParams());
relativeLayoutParams.setMargins(relativeLayoutParams.leftMargin, relativeLayoutParams.topMargin, joStyle.getInt("marginRight"), relativeLayoutParams.bottomMargin);
}
if (relativeLayoutParams != null) {
v.setLayoutParams(relativeLayoutParams);
}
} catch (Exception e) {
Helper.logError("", e);
}
}
}
public static String getSdcardPath() {
if(sdcardPath == null)
sdcardPath = ctx.getApplicationInfo().dataDir;
return sdcardPath;
}
public static String getResourcesPath() {
return getSdcardPath() + "/resources/";
}
public static String getCSSPath() {
return getResourcesPath() + "default.css";
}
public static String getImagesPath() {
return getResourcesPath() + "images/" + ResourceConstants.getScreenDPI(ctx) + "/";
}
public static String getImagesPathNoDpi() {
return getResourcesPath() + "images/";
}
public static NinePatchDrawable loadNinePatchFromFilesystem(String filename) {
if(ninePatchHashMaps == null)
ninePatchHashMaps = new ArrayList<HashMap<String, NinePatchDrawable>>();
// check if we already have this filename so we can reuse it
for (int i = 0; i < ninePatchHashMaps.size(); i++) {
HashMap<String, NinePatchDrawable> row = ninePatchHashMaps.get(i);
if(row.containsKey(filename))
return row.get(filename);
}
NinePatchDrawable patchy = null;
try {
BitmapFactory.Options options = new BitmapFactory.Options();
options.inPreferredConfig = Bitmap.Config.ARGB_8888;
Bitmap bitmap = BitmapFactory.decodeFile(filename, options);
byte[] chunk = bitmap.getNinePatchChunk();
boolean result = NinePatch.isNinePatchChunk(chunk);
if (result)
patchy = new NinePatchDrawable(bitmap, chunk, new Rect(), null);
} catch (Exception e){
Helper.logError("NinePatchLoading",e);
}
if(patchy != null) {
HashMap<String, NinePatchDrawable> drawableImage = new HashMap<String, NinePatchDrawable>();
drawableImage.put(filename, patchy);
ninePatchHashMaps.add(drawableImage);
}
return patchy;
}
public static Drawable loadImageFromFilesystem(String filename) {
if(imagesHashMaps == null)
imagesHashMaps = new ArrayList<HashMap<String, Drawable>>();
// check if we already have this filename so we can reuse it
for (int i = 0; i < imagesHashMaps.size(); i++) {
HashMap<String, Drawable> row = imagesHashMaps.get(i);
if(row.containsKey(filename))
return row.get(filename);
}
Drawable image = null;
try {
BitmapFactory.Options options = new BitmapFactory.Options();
options.inPreferredConfig = Bitmap.Config.ARGB_8888;
Bitmap bitmap = BitmapFactory.decodeFile(filename, options);
if(bitmap == null)
bitmap = BitmapFactory.decodeFile(filename.replace(ResourceConstants.getScreenDPI(ctx) + "/", ""), options);
image = new BitmapDrawable(bitmap);
} catch (Exception e){
Helper.logError("ImageLoadingError",e);
}
if(image != null) {
HashMap<String, Drawable> drawableImage = new HashMap<String, Drawable>();
drawableImage.put(filename, image);
imagesHashMaps.add(drawableImage);
}
return image;
}
}

Implementing efficient cache system [duplicate]

My android app gets its data using REST API. I want to have client side caching implemented. Do we have any inbuilt classes for this?
if not, is these any code that i can reuse? I remember coming across such code sometime back. However I cant find it.
If nothing else works, i will write my own. following is basic structure
public class MyCacheManager {
static Map<String, Object> mycache;
public static Object getData(String cacheid) {
return mycache.get(cacheid);
}
public static void putData(String cacheid, Object obj, int time) {
mycache.put(cacheid, obj);
}
}
how do i enable time for cached objects? also - whats the best way to serialize? cache should be intact even if app is closed and reopened later (if time has not expired).
Thanks
Ajay

Now awesome library Volley released on Google I/O 2013 which helps for improve over all problems of calling REST API:
Volley is a library,it is library called Volley from the Android dev team. that makes networking for Android apps easier and most importantly, faster. It manages the processing and caching of network requests and it saves developers valuable time from writing the same network call/cache code again and again. And one more benefit of having less code is less number of bugs and that’s all developers want and aim for.
Example for volley: technotalkative

One of the best ways is to use Matthias Käppler's ignited librarys to make http requests that caches the responses in memory (weak reference) and on file. Its really configurable to do one or the other or both.
The library is located here : https://github.com/mttkay/ignition with examples located here : https://github.com/mttkay/ignition/wiki/Sample-applications
Personally, I love this lib from when it was called Droidfu
Hope this helps you as much as it did me Ajay!

First check the device is connected from the internet or not.
public class Reachability {
private final ConnectivityManager mConnectivityManager;
public Reachability(Context context) {
mConnectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
}
public boolean isConnected() {
NetworkInfo networkInfo = mConnectivityManager.getActiveNetworkInfo();
return networkInfo != null && networkInfo.isConnectedOrConnecting();
}}
If device is connected from internet then get the data from API and cache it else get the data from cache.
public class CacheManager {
Cache<String, String> mCache;
private DiskLruCache mDiskLruCache;
private final Context mContext;
public CacheManager(Context context) throws IOException {
mContext = context;
setUp();
mCache = DiskCache.getInstanceUsingDoubleLocking(mDiskLruCache);
}
public void setUp() throws IOException {
File cacheInFiles = mContext.getFilesDir();
int version = BuildConfig.VERSION_CODE;
int KB = 1024;
int MB = 1024 * KB;
int cacheSize = 400 * MB;
mDiskLruCache = DiskLruCache.open(cacheInFiles, version, 1, cacheSize);
}
public Cache<String, String> getCache() {
return mCache;
}
public static class DiskCache implements Cache<String, String> {
private static DiskLruCache mDiskLruCache;
private static DiskCache instance = null;
public static DiskCache getInstanceUsingDoubleLocking(DiskLruCache diskLruCache){
mDiskLruCache = diskLruCache;
if(instance == null){
synchronized (DiskCache.class) {
if(instance == null){
instance = new DiskCache();
}
}
}
return instance;
}
#Override
public synchronized void put(String key, String value) {
try {
if (mDiskLruCache != null) {
DiskLruCache.Editor edit = mDiskLruCache.edit(getMd5Hash(key));
if (edit != null) {
edit.set(0, value);
edit.commit();
}
}
} catch (IOException e) {
e.printStackTrace();
}
}
#Override
public synchronized String get(String key) {
try {
if (mDiskLruCache != null) {
DiskLruCache.Snapshot snapshot = mDiskLruCache.get(getMd5Hash(key));
if (snapshot == null) {
// if there is a cache miss simply return null;
return null;
}
return snapshot.getString(0);
}
} catch (IOException e) {
e.printStackTrace();
}
// in case of error in reading return null;
return null;
}
#Override
public String remove(String key) {
// TODO: implement
return null;
}
#Override
public void clear() {
// TODO: implement
}
}
public static String getMd5Hash(String input) {
try {
MessageDigest md = MessageDigest.getInstance("MD5");
byte[] messageDigest = md.digest(input.getBytes());
BigInteger number = new BigInteger(1, messageDigest);
String md5 = number.toString(16);
while (md5.length() < 32)
md5 = "0" + md5;
return md5;
} catch (NoSuchAlgorithmException e) {
Log.e("MD5", e.getLocalizedMessage());
return null;
}
}}
Create the CacheInterceptor class to cache the network response and handle the errors
public class CacheInterceptor implements Interceptor{
private final CacheManager mCacheManager;
private final Reachability mReachability;
public CacheInterceptor(CacheManager cacheManager, Reachability reachability) {
mCacheManager = cacheManager;
mReachability = reachability;
}
#Override
public Response intercept(Chain chain) throws IOException {
Request request = chain.request();
String key = request.url().toString();
Response response;
if (mReachability.isConnected()) {
try {
response = chain.proceed(request);
Response newResponse = response.newBuilder().build();
if (response.isSuccessful()) {
if (response.code() == 204) {
return response;
}
// save to cache this success model.
mCacheManager.getCache().put(key, newResponse.body().string());
// now we know that we definitely have a cache hit.
return getCachedResponse(key, request);
}else if (response.code() >= 500) { // accommodate all server errors
// check if there is a cache hit or miss.
if (isCacheHit(key)) {
// if data is in cache, the return the data from cache.
return getCachedResponse(key, request);
}else {
// if it's a miss, we can't do much but return the server state.
return response;
}
}else { // if there is any client side error
// forward the response as it is to the business layers to handle.
return response;
}
} catch (ConnectException | UnknownHostException e) {
// Internet connection exception.
e.printStackTrace();
}
}
// if somehow there is an internet connection error
// check if the data is already cached.
if (isCacheHit(key)) {
return getCachedResponse(key, request);
}else {
// if the data is not in the cache we'll throw an internet connection error.
throw new UnknownHostException();
}
}
private Response getCachedResponse(String url, Request request) {
String cachedData = mCacheManager.getCache().get(url);
return new Response.Builder().code(200)
.body(ResponseBody.create(MediaType.parse("application/json"), cachedData))
.request(request)
.protocol(Protocol.HTTP_1_1)
.build();
}
public boolean isCacheHit(String key) {
return mCacheManager.getCache().get(key) != null;
}}
Now add the this interceptor in OkHttpClient while creating the service using Retrofit.
public final class ServiceManager {
private static ServiceManager mServiceManager;
public static ServiceManager get() {
if (mServiceManager == null) {
mServiceManager = new ServiceManager();
}
return mServiceManager;
}
public <T> T createService(Class<T> clazz, CacheManager cacheManager, Reachability reachability) {
return createService(clazz, HttpUrl.parse(ServiceApiEndpoint.SERVICE_ENDPOINT), cacheManager, reachability);
}
private <T> T createService(Class<T> clazz, HttpUrl parse, CacheManager cacheManager, Reachability reachability) {
Retrofit retrofit = getRetrofit(parse, cacheManager, reachability);
return retrofit.create(clazz);
}
public <T> T createService(Class<T> clazz) {
return createService(clazz, HttpUrl.parse(ServiceApiEndpoint.SERVICE_ENDPOINT));
}
private <T> T createService(Class<T> clazz, HttpUrl parse) {
Retrofit retrofit = getRetrofit(parse);
return retrofit.create(clazz);
}
private <T> T createService(Class<T> clazz, Retrofit retrofit) {
return retrofit.create(clazz);
}
private Retrofit getRetrofit(HttpUrl httpUrl, CacheManager cacheManager, Reachability reachability) {
return new Retrofit.Builder()
.baseUrl(httpUrl)
.client(createClient(cacheManager, reachability))
.addConverterFactory(getConverterFactory())
.build();
}
private OkHttpClient createClient(CacheManager cacheManager, Reachability reachability) {
return new OkHttpClient.Builder().addInterceptor(new CacheInterceptor(cacheManager, reachability)).build();
}
private Retrofit getRetrofit(HttpUrl parse) {
return new Retrofit.Builder()
.baseUrl(parse)
.client(createClient())
.addConverterFactory(getConverterFactory()).build();
}
private Retrofit getPlainRetrofit(HttpUrl httpUrl) {
return new Retrofit.Builder()
.baseUrl(httpUrl)
.client(new OkHttpClient.Builder().build())
.addConverterFactory(getConverterFactory())
.build();
}
private Converter.Factory getConverterFactory() {
return GsonConverterFactory.create();
}
private OkHttpClient createClient() {
return new OkHttpClient.Builder().build();
}}
Cache interface
public interface Cache<K, V> {
void put(K key, V value);
V get(K key);
V remove(K key);
void clear();}

Android: Make App accessible without internet connection

so I made an app which communicates with JSON on the web. It fetches images and texts from the JSON.
And now I got a task to make this app accessible without an internet connection.
it should be like this:
The first time it's launched, the app has to check if there's any internet connection or not. If not, pop up a dialog box 'Please check your internet connection'. If there's any, the app is opened and it has to download the images and texts from the JSON and save them into an external storage
The next time when the app is opened, when there's no internet it will load the images and text files from the external storage. And each time it's connected to the internet, it will download the files and replace the previous files.
Can anybody provide me a solution by modifying these classes below maybe?
public class ImageThreadLoader {
private static final String TAG = "ImageThreadLoader";
// Global cache of images.
// Using SoftReference to allow garbage collector to clean cache if needed
private final HashMap<String, SoftReference<Bitmap>> Cache = new HashMap<String, SoftReference<Bitmap>>();
private final class QueueItem {
public URL url;
public ImageLoadedListener listener;
}
private final ArrayList<QueueItem> Queue = new ArrayList<QueueItem>();
private final Handler handler = new Handler(); // Assumes that this is started from the main (UI) thread
private Thread thread;
private QueueRunner runner = new QueueRunner();;
/** Creates a new instance of the ImageThreadLoader */
public ImageThreadLoader() {
thread = new Thread(runner);
}
/**
* Defines an interface for a callback that will handle
* responses from the thread loader when an image is done
* being loaded.
*/
public interface ImageLoadedListener {
public void imageLoaded(Bitmap imageBitmap );
}
/**
* Provides a Runnable class to handle loading
* the image from the URL and settings the
* ImageView on the UI thread.
*/
private class QueueRunner implements Runnable {
public void run() {
synchronized(this) {
while(Queue.size() > 0) {
final QueueItem item = Queue.remove(0);
// If in the cache, return that copy and be done
if( Cache.containsKey(item.url.toString()) && Cache.get(item.url.toString()) != null) {
// Use a handler to get back onto the UI thread for the update
handler.post(new Runnable() {
public void run() {
if( item.listener != null ) {
// NB: There's a potential race condition here where the cache item could get
// garbage collected between when we post the runnable and it's executed.
// Ideally we would re-run the network load or something.
SoftReference<Bitmap> ref = Cache.get(item.url.toString());
if( ref != null ) {
item.listener.imageLoaded(ref.get());
}
}
}
});
} else {
final Bitmap bmp = readBitmapFromNetwork(item.url);
if( bmp != null ) {
Cache.put(item.url.toString(), new SoftReference<Bitmap>(bmp));
// Use a handler to get back onto the UI thread for the update
handler.post(new Runnable() {
public void run() {
if( item.listener != null ) {
item.listener.imageLoaded(bmp);
}
}
});
}
}
}
}
}
}
/**
* Queues up a URI to load an image from for a given image view.
*
* #param uri The URI source of the image
* #param callback The listener class to call when the image is loaded
* #throws MalformedURLException If the provided uri cannot be parsed
* #return A Bitmap image if the image is in the cache, else null.
*/
public Bitmap loadImage( final String uri, final ImageLoadedListener listener) throws MalformedURLException {
// If it's in the cache, just get it and quit it
if( Cache.containsKey(uri)) {
SoftReference<Bitmap> ref = Cache.get(uri);
if( ref != null ) {
return ref.get();
}
}
QueueItem item = new QueueItem();
item.url = new URL(uri);
item.listener = listener;
Queue.add(item);
// start the thread if needed
if( thread.getState() == State.NEW) {
thread.start();
} else if( thread.getState() == State.TERMINATED) {
thread = new Thread(runner);
thread.start();
}
return null;
}
/**
* Convenience method to retrieve a bitmap image from
* a URL over the network. The built-in methods do
* not seem to work, as they return a FileNotFound
* exception.
*
* Note that this does not perform any threading --
* it blocks the call while retrieving the data.
*
* #param url The URL to read the bitmap from.
* #return A Bitmap image or null if an error occurs.
*/
public static Bitmap readBitmapFromNetwork( URL url ) {
InputStream is = null;
BufferedInputStream bis = null;
Bitmap bmp = null;
try {
URLConnection conn = url.openConnection();
conn.connect();
is = conn.getInputStream();
bis = new BufferedInputStream(is);
bmp = BitmapFactory.decodeStream(bis);
} catch (MalformedURLException e) {
Log.e(TAG, "Bad ad URL", e);
} catch (IOException e) {
Log.e(TAG, "Could not get remote ad image", e);
} finally {
try {
if( is != null )
is.close();
if( bis != null )
bis.close();
} catch (IOException e) {
Log.w(TAG, "Error closing stream.");
}
}
return bmp;
}
}
and
public class ProjectAdapter extends ArrayAdapter<Project> {
int resource;
String response;
Context context;
private final static String TAG = "MediaItemAdapter";
private ImageThreadLoader imageLoader = new ImageThreadLoader();
//Initialize adapter
public ProjectAdapter(Context context, int resource, List<Project> items) {
super(context, resource, items);
this.resource=resource;
}
#Override
public View getView(int position, View convertView, ViewGroup parent)
{
TextView textTitle;
final ImageView image;
Project pro = getItem(position);
LinearLayout projectView;
//Inflate the view
if(convertView==null)
{
projectView = new LinearLayout(getContext());
String inflater = Context.LAYOUT_INFLATER_SERVICE;
LayoutInflater vi;
vi = (LayoutInflater)getContext().getSystemService(inflater);
vi.inflate(resource, projectView, true);
}
else
{
projectView = (LinearLayout) convertView;
}
try {
textTitle = (TextView)projectView.findViewById(R.id.txt_title);
image = (ImageView)projectView.findViewById(R.id.image);
} catch( ClassCastException e ) {
Log.e(TAG, "Your layout must provide an image and a text view with ID's icon and text.", e);
throw e;
}
Bitmap cachedImage = null;
try {
cachedImage = imageLoader.loadImage(pro.smallImageUrl, new ImageLoadedListener() {
public void imageLoaded(Bitmap imageBitmap) {
image.setImageBitmap(imageBitmap);
notifyDataSetChanged(); }
});
} catch (MalformedURLException e) {
Log.e(TAG, "Bad remote image URL: " + pro.smallImageUrl, e);
}
textTitle.setText(pro.project_title);
if( cachedImage != null ) {
image.setImageBitmap(cachedImage);
}
return projectView;
}
}
Thank you!

Create a database with the names and paths of the downloaded images. Upon onCreate() (or wherever you want to do the check), read the database and check if it's empty or not. If not, then use the images.