The problem is this:
I make an internet connection to some url and receive an HttpResponse with an app_example.apk.
Then I want to create a file (an .apk)
in the sdcard with this data so that this downloaded application
can be installed later.
How can I convert the HttpResponse to an .apk file?
Let's clear some details:
I have to get this apk file through an internet connection to my server
I don't want to install this applications I receive on the sdcard
All of this has to be done in my code, I cannot use android market
I am currently writing to that file.
What I'm doing is converting the HttpResponse to a byte[ ],
then that byte[ ] is written to a file (an .apk) using an ObjectOutputStream.
Like this:
// byte[] appByteArray - already has the internet response converted in bytes
try {
file = new File(Environment.getExternalStorageDirectory()+"/"+appName+".apk");
file.createNewFile();
FileOutputStream stream = null;
stream = new FileOutputStream(file, false);
ObjectOutputStream objectOut =
new ObjectOutputStream(new BufferedOutputStream(stream));
objectOut.writeObject(appByteArray);
objectOut.close();
} catch (Exception e) {
e.printStackTrace();
}
In the end, the file is created
and has the received content.
When I try to install it,
through a VIEW intent (using the default installer)
I get a parse error saying that it could not find the AndroidManifest.xml.
I think that in some step along the way, the received data is being corrupted.
Do you have another method to solve this?
Many thanks
Don't use an ObjectOutputStream, byte array is serialized as Object, not written as raw data.
Are you sure that you have SD card write permission? android.permission.WRITE_EXTERNAL_STORAGE
Don't write into SD card root directory. Number of files in root dir can be limited. Instead create you app subdirectory on SD CARD.
This code works for me:
try {
String filePath = Environment.getExternalStorageDirectory()
+ "/myappdir/" + appName + ".apk";
File file = new File(filePath);
file.getParentFile().mkdirs();
file.createNewFile();
BufferedOutputStream objectOut = new BufferedOutputStream(
new FileOutputStream(file));
objectOut.write(appByteArray);
objectOut.close();
} catch (Exception e) {
e.printStackTrace();
}
This may not be the core problem, but I don't think you want to wrap stream in an ObjectOutputStream, since that is used for object serialization. It could be that it is adding extra data to the file so it can be deserialized with ObjectInputStream.
I would try pulling the apk off of the emulator (or device) and check it's MD5 versus the file on the server to make sure that the bits are being written out correctly.
Take a look at Pavel P's answer.
Also, I would note that your idea of installing the APK using the VIEW intent action does work, as I have tested this technique in the past.
However, unless the user has explicitly gone into Settings → Applications and selected "Allow non-Market applications", your installation will fail and the user will just see a screen telling them that for security reasons the installation has been blocked.
Basically you really need to rely on having fairly tech-savvy users who are willing to overlook a scary security warning and go and disable that setting.
Related
To be as succinct as possible:
-APK file is not corrupt.
-I can browse to the APK in the phone's file system and manually install it from there without issue.
-I am using the following code to kick off the install process. File location is confirmed correct:
public void installfromlocal()
{
String downloadfilelocation = getsharedresourcestring("updatepackagelocation");
Log.e("installing from",downloadfilelocation);
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(Uri.fromFile(new File(downloadfilelocation)), "application/vnd.android.package-archive");
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
So far what I could gather from a couple hours on the internet is that apparently I can't make my app install an APK programmatically from external storage. I can also apparently not copy the file to internal storage and install from there.
So what now? Additionally, I get no messages from Logcat. I only get a popup alerting me that there was an error parsing the apk.
I found a solution for me (not so clear why have this issue, but i solve it).
It seems to me that when downloading with DownloadManager you cant access to the downloaded file via URI, and you get access denied (and various file not found exception error) that's why PackageInstaller cannot read at all the manifest (and that's the parse error).
This is what i did, i hope that resolve you problem as well, i know it's not elegant to say the least.
Because of DownloadManager.COLUMN_LOCAL_FILENAME is deprecated i tried with COLUMN_LOCAL_URI to access the file and access its content (q is Cursor)
String strUri = q.getString(q.getColumnIndex(DownloadManager.COLUMN_LOCAL_URI));
Uri apkUri = Uri.parse(strUri);
with this uri i can access and copy the file to a temp file in getExternalCacheDir()
ParcelFileDescriptor pfd = context.getContentResolver().openFileDescriptor(apkUri, "r");
InputStream inFile = new FileInputStream(pfd.getFileDescriptor());
OutputStream outFile = new FileOutputStream(tmpFile);
//copy
byte[] buffer = new byte[1024];
int length;
while ((length = inFile.read(buffer)) > 0) {
outFile.write(buffer, 0, length);
}
outFile.flush();
inFile.close();
outFile.close();
Grab the file created and get its uri (that is accessible) and start the activity with that uri.
I hope it helps
You should use canonical path of the file. From the docs-
A canonical pathname is both absolute and unique. The precise definition of canonical form is system-dependent. This method first converts this pathname to absolute form if necessary, as if by invoking the getAbsolutePath() method, and then maps it to its unique form in a system-dependent way. This typically involves removing redundant names such as "." and ".." from the pathname, resolving symbolic links (on UNIX platforms), and converting drive letters to a standard case (on Microsoft Windows platforms).
I have wrote a json file with data I will get it to recycleview in android but I don't know where can I upload this file to access it into android project
There are 2 ways you can do that:
Local Storage: You can save a JSON file in your project locally. (already answered by others)
Upload your JSON: You can upload your JSON at jsonbin.io and it will generate an API that you can use in your project.
You can store JSON file in your assets folder......
void saveStringToFile(String path, String content) {
try {
File newFile = new File(path);
newFile.createNewFile();
FileOutputStream fos = new FileOutputStream(newFile);
fos.write(content.getBytes());
fos.flush();
fos.close();
Constant.logD("File "+ newFile.getName()+ " is saved successfully at "+ newFile.getAbsolutePath());
} catch (Exception e) {
Constant.logE("Unable to save file", e);
}
}
Mention a path in a mobile sdcard like Environment.getExternalStorageDirectory().getAbsolutePath()+"/" + System.currentTimeMillis()+".jpg" as path
Based on your requirement:
Best option is to host it on a (web server if you have one)
If you don't, share the file on GDrive or Dropbox (or similar hosting services which provide free storage). Share it with read-only access for your app to read from.
You can put your json file in the assets folder and best option is host the json file on the server and use the data (API) in your project.
Having a problem writing out to a file, this code is taken directly from the android developer page and then tweaked a bit by me. Is there something i am missing? Quite new to Android development so sorry if it's something blatantly obvious.
send.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
FileOutputStream outputStream;
String data = "hello";
File fileDir = new File("data.txt");
if (!fileDir.exists())
fileDir.mkdirs();
try {
outputStream = openFileOutput("data.txt",Context.MODE_PRIVATE);
outputStream.write(data.getBytes());
outputStream.close();
} catch (Exception e) {
e.printStackTrace();
}
}
});
Basically, your problem is that you are trying to do it twice, once in a way that won't work, and once in a way that will, but hides the result.
File fileDir = new File("data.txt");
if (!fileDir.exists())
fileDir.mkdirs();
This would create a Java File object connected to a hypothetical file called "data.txt" located in the current working directory, which for an Android app is the root directory of the device - a place you most definitely are not allowed to write to. However, this may not obviously cause any errors, as the root directory exists so mkdirs() will do nothing, and you only create a File object, you don't actually try to create a file on "disk". Effectively this code does nothing for you - get rid of it.
Next you try something basically workable:
try {
outputStream = openFileOutput("data.txt",Context.MODE_PRIVATE);
outputStream.write(data.getBytes());
outputStream.close();
} catch (Exception e) {
e.printStackTrace();
}
openFileOutput() is a method of a Context (Activity or Service) which creates an output stream to write to an actual file located in the private internal storage area of your app. This is all fine and good, and normally a good choice for storing typical data. However, it is not a place that you will be able to examine when running a release app on a secured device, as neither ADB based tools nor Mass Storage or MTP access over USB have rights to it. So it's entirely possible that this code worked, but you had no way to discover that fact. If you are on an emulator, you can access this location with ADB or the DDMS browser, and if your apk is a debug one, you can use the run-as command line tool in the shell.
If you want to share the data, you might consider putting it on the External Storage instead.
I'm having a little problem with my android app.
My app generates a .html file when a "export button" is pressed.
But I can't see the file in my pc or in the Android's Download app. I can only see it in Astro file manager.
That's how I generate and saved my file .
String string = "Hello World"
String filename = "/sdcard/Download/teste.html";
FileOutputStream outputStream;
try {
File file = new File(filename);
boolean newFile = file.createNewFile();
if(!newFile){ //if the file exists I delete it and generate a new file
file.delete();
newFile=file.createNewFile();
}
Context context=getActivity();
FileOutputStream fOut = new FileOutputStream(file,true);
// Write the string to the file
fOut.write(string.getBytes());
/* ensure that everything is
* really written out and close */
fOut.flush();
fOut.close();
}
catch (Exception e) {
e.printStackTrace();
}
I suppose there is a way to visualize this file without the Astro app but I can't find how do this, if someone can help I'll be grateful.
Thanks
First, never hardcode paths. Your path will be wrong on some Android devices. Please use the proper methods on Environment (e.g., getExternalStoragePublicDirectory()) or Context (e.g., getExternalFilesDir()) to get the roots under which you can safely place files.
Beyond that, files that you write to external storage will not be visible to PCs until that file is indexed by MediaScannerConnection, and even then it might require the user to perform some sort of "reload" or "refresh" operation in their file browser to see it.
I have another blog post with more about external storage which may be of use to you.
Okay, I seem to be having a small issue with R.drawable.balloons. I'm trying to use a template for building a private external storage file that I found on Android Developer, but balloons keeps giving an error (cannot be resolved or is not a field). I was wondering if I could get some help fixing it.
Here's the code section it sits in:
void createExternalStoragePrivateFile() {
// Create a path where we will place our private file on external
// storage.
File file = new File(getExternalFilesDir(null), "DemoFile.jpg");
try {
/*
Very simple code to copy a picture from the application's
resource into the external file. Note that this code does
no error checking, and assumes the picture is small (does not
try to copy it in chunks). Note that if external storage is
not currently mounted this will silently fail.
*/
// Creates file to stream picture
OutputStream os = new FileOutputStream(file);
// Allows app to accept the picture
InputStream is = getResources().openRawResource(R.drawable.balloons);
byte[] data = new byte[is.available()];
is.read(data);
os.write(data);
is.close();
os.close();
} catch (IOException e) {
// Unable to create file, likely because external storage is
// not currently mounted.
Log.w("ExternalStorage", "Error writing " + file, e);
}
}
A heads up, in case I get called out for being a copy/paster, this is only supposed to be a template, but I would like to test that it works before I make changes. Sorry.
You need an image named balloons in the res\drawable folder of your project (or any of its variants, such as drawable-hdpi, &c). The R class is autogenerated.
See How do I add R drawable android?