Develop Reference

Error while loading gif image source

I tried executing the following line to load gif image, programatically.
gifInputStream = context.getResources().openRawResource(R.drawable.image);
But, studio used to indicate an error near "R.drawable.image".

I found a solution, or rather hack around to my issue. I just added "+" symbol. So, the line looks like this now...
gifInputStream = context.getResources().openRawResource(+R.drawable.image);
AndroidStudio doesn't show any error now.

it required raw file not drawable.
Please create res/raw/ directory and move your file in the raw directory.
after then:-
context.getResources().openRawResource(R.raw.yourfilename)

How to get path to file in android apk

My app depends on 3 different files. I already put the two larger ones as expansion files which seems to work fine. Now I don't know where to put the third one (small file). I tried the raw folder but actually I don't know what the path of the file is once it is in those folders.
I tried this here for the raw folder
myClassifier.loadModel( pathToExpansionFiles + "/File1",
pathToExpansionFiles + "/File2",
R.raw.File3);
However the return value of R.raw.File3 is an integer, but the function myClassifier expects a string that is the path to File3. Has anyone an idea how to do that?

I tried the raw folder but actually I don't know what the path of the file is once it is in those folders.
There is no path to it. That is a file on your development machine. It is not a file on the device. It is merely an entry inside your APK file.
but the function myClassifier expects a string that is the path to File3
Either switch to some library that works with an InputStream (from getResources().openRawResource()) or make a copy of the data to a local file using that InputStream yourself.

C++ OpenCV imread not working in Android

I am trying to read an image in my C++ code
LOGD("Loading image '%s' ...\n", (*inFile).c_str());;
Mat img = imread(*inFile, CV_LOAD_IMAGE_GRAYSCALE);
CV_Assert(img.data != 0);
and get the following output:
09-25 17:08:24.798: D/IRISREC(12120): Loading image '/data/data/com.example.irisrec/files/input/osoba1.jpg' ...
09-25 17:08:24.798: E/cv::error()(12120): OpenCV Error: Assertion failed (img.data != 0) in int wahet_main(int, char**), file jni/wahet.cpp, line 4208
The file exists. But strange is, that if I try to preview the image using Root File Browser it is just black. I copied the files there manually.
EDIT:
The code works fine under Windows with .png and .jpg format. I am just trying to port an existing C++ project for Iris Recognition to Android.

imread() determines the type of file based on its content not by the file extension. If the header of the file is corrupted, it makes sense that the method fails.
Here are a few things you could try:
Copy those images back to the computer and see if they can be opened by other apps. There's a chance that they are corrupted in the device;
Make sure there is a file at that location and that your user has permission to read it;
Test with types of images (jpg, png, tiff, bmp, ...);
For testing purposes it's always better to be more direct. Get rid of inFile:
Example:
Mat img = imread("/data/data/com.example.irisrec/files/input/osoba1.jpg", CV_LOAD_IMAGE_GRAYSCALE);
if (!img.data) {
// Print error message and quit
}

When debugging, first try to get more data on the problem.
It's an unfortunate design that imread() doesn't provide any error info. The docs just say that it'll fail "because of missing file, improper permissions, unsupported or invalid format".
Use the debugger to step into the code if you can. Can you tell where it fails?
Search for known problems, stackoverflow.com/search?q=imread, e.g. imread not working in OpenCV.
Then generate as many hypotheses as you can. For each one, think of a way to test it. E.g.
The image file is malformed (as #karlphillip offered). -- See if other software can open the file.
The image file is not a supported format. -- Verify the file format on your desktop. Test that desktop OpenCV can read it. Check the docs to verify the image formats that AndroidCV can read.
The image file is not at the expected path. -- Write code to test if there's a file at that path, and verify its length.
The image file does not have read permission. -- Write code to open the file for reading.
A problem with the imread() arguments. -- Try defaulting the second argument.

I was able to solve this issue only by copying the image files in code.I stored them in my asset folder first and copied them to internal storage following this example.
If someone can explain this to me please do this.

It could be a permission issue.You would have to request the permission from Java code in your Activity class like this in Android 6.0 or above. Also make sure that in your AndroidManifest.xml, you have the the following line :
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
In your activity file add this:
if (PermissionUtils.requestPermission(
this,
HOME_SCREEN_ACTIVITY,
Manifest.permission.READ_EXTERNAL_STORAGE)) {
Mat image = Imgcodecs.imread(filePath,Imgcodecs.IMREAD_COLOR);
}
I struggled a long time to find this and I was getting Mat object null for all the time before.

File not found issue in Android

I need to access myfile.txt file using FileReader in Android , please suggest me where to add the text file in Eclipse. I tried it adding it in Resource and Asset but I am getting File not found issue.
FileReader fr = new FileReader("myfile.txt");
Even
File ff = new File("myfile.txt");
File Supports only the below listed parameters
FileReader Supports only the below listed parameters
Note: I want solution for this issue , only with FileReader or File

The directory would be /res/raw/ this is where you put all your extra resources.
you can refer to it using getResources().openRawResource(resourceName)
and check here Android how to get access to raw resources that i put in res folder?
EDIT:
how can i edit the text files in assets folder in android
in short
the easiest way would be to copy the file to external directory then do your stuff there
link is here
Android: How to create a directory on the SD Card and copy files from /res/raw to it?
One thing to mention - prior to 2.3 the file size in the assets cannot exceed 1MB.
hope it helps abit

That's how I obtain my file from the SD card, perhaps this can be some use to you.
String state = Environment.getExternalStorageState();
if (Environment.MEDIA_MOUNTED.equals(state)) {
File options = new File(getAppDirectory(), "portal.xml");
}
The getAppDirectory method used in the bit of code looks like this :
private String getAppDirectory() {
return new String(Environment.getExternalStorageDirectory().toString()
+ "/foldername/foldername/");
}
After this bit of code I also make sure the file exists and what not before I attempt to read from it.

android: Check the existence of a file in the application

I have few html files in assets folder of my application. My application loads these files depending on the device language. When I check for the existance of the file it say does not exist, but when I load that file using browser.loadUrl(filename), it loads it fine.
Following code will help you to understand my problem:
String filename="file:///android_asset/actualfilemname.html";
File f = new File(filename);
if(!f.exist){
filename = "file:///android_asset/newfile.html";[Everytime it loads this file even though I have actualfilename.html in the folder]
}
browser.loadUrl(filename);
[it loads the newfile.html but not actualfilename.html]

You can't use File for resources. You'll need to use the AssetManager for that.
(In the off-chance that File does handle resources, which I don't think it does, you'll have to convert the path to a URI first, for example using URI.create(). File(String) expects a path, not a URI.)

Is this the exact code you are using? you probably want to be calling f.exists() not filename.exist().
Edit: try working with the AssetManager instead of hard coding your file path. My best guess is that the file path you are using is not exactly how it supposed to be.