Develop Reference

How to access flutter jni `/storage/emulated/0/Documents/` folder

You need to read data from a file that exists in the path /storage/emulated/0/Documents/. There is no problem in checking the existence of a file. But I access this path with 'jni' i.e. 'C' code and read the data from the file.
Failed to open file due to permission problem.
Is there a way to access files in /storage/emulated/0/Documents/ in jni C?
permission
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.MANAGE_EXTERNAL_STORAGE" />
//in <application...
android:requestLegacyExternalStorage="true"
android:preserveLegacyExternalStorage="true"
code
int nResult = (i ~/ 100) * 100;
File agingFile = File("/storage/emulated/0/Documents/$nResult/$i.C03");
await platform.invokeMethod("readFile", agingFile.path);
///JAVA
if(call.method.equals("readFile")){
String path = call.arguments();
ReadFile(path);
}

file.exists() return false

File oldFile = new File(dirPath+"/"+packageName+".apk");
Log.e("Path ",oldFile.getPath());
my log returns this:
E/Path:
/storage/emulated/0/Android/data/com.bazibaaz.app/files/com.YGD.GoldenBasket.apk
i have this file exactly on the path shown in the log, but this code:
oldFile.exists()
returns false!
i have permissions to read and write:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
here is the picture of file (to prove its existence):
( path: internal storage/storage/emulated/0/Android/data/com.bazibaaz.app/files/com.YGD.GoldenBasket.apk)

Can't create folder and file

I'm trying to create folder in internal storage of the device, and have some problems with that. I can't create directory using :
String rootPath=Environment.getExternalStorageDirectory().getPath()+"/test";
File file=new File(rootPath);
if(!file.exists()){
file.mkdir();
}
file.mkdir return false
I have such permissions:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_INTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_INTERNAL_STORAGE" />
Thank you very much for answers !

So really, as you all guys said in Android Marshmallow (API 23) or higher we need to ask runtime permissions.
To solve this issue use call :
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
in your onCreate() method
Thanks all for your help !

You can use
File sampleDir = new File(Environment.getExternalStorageDirectory(), "/test");
if (!sampleDir.exists()) {
sampleDir.mkdirs();
}

Permission denied Exception when creating new file

i want to create new file iam using this code
try {
File file = new File(Environment.getExternalStorageDirectory() + File.separator + "Contacts.vcf");
file.createNewFile();
} catch (IOException ioe)
{ioe.printStackTrace();}
and using this permission
<permission android:name="android.permission.MOUNT_FORMAT_FILESYSTEMS" ></permission>
but it keeps givinh me exeption that says Permission denied

you need to use this permission in manifest file
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

when you write any file in External Storage(SD CARD) or Internal Storage ,You have to add permission in manifest file...
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

add this permission into your manifest file
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

Give WRITE_EXTERNAL_STORAGE permission to your AndroidManifest file as shown below:
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
.........
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
</manifest>

MediaRecorder issue - throws FileNotFoundException when I try to write to sdcard

Here is the exact exception that's thrown:
java.io.FileNotFoundException: /mnt/sdcard/example.mp4 (Permission denied)
I literally copied and pasted example code from here. In addition, I also added this little bit of code to format my path correctly:
private String sanitizePath(String path) {
if (!path.startsWith("/")) {
path = "/" + path;
}
if (!path.contains(".")) {
path += ".3gp";
}
return Environment.getExternalStorageDirectory().getAbsolutePath() + path;
}
Here are the permissions included in my manifest:
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.RECORD_VIDEO" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.STORAGE" />
<uses-feature android:name="android.hardware.camera"/>
<uses-feature android:name="android.hardware.camera.front"/>
Am I missing something completely obvious or is it something more?

You might want to check if the phone is in "Mass Storage Mode".
When USB cable is connected in this mode, you cannot access files on /sdcard.