I am new to Android and mostly using snippets of code from other posts to build my project. I am having a hard time creating a new directory and file on my device. I am using the following code, but I am unable to verify the success of the creation of this path. I want to be able to mount my phone to my laptop and find a file named "MyRecording.pcm" in a folder "/My/Files". I am using the boolean value of mkdirs() to verify whether or not the path was created on my device. If that path was not created then my TextView will tell me "Directories do not exist"; otherwise, my code will create the file MyRecording.pcm. I keep getting an error/warning "result of mkdirs() is ignored". Please help.
File path = new File(Environment.getExternalStorageDirectory() + "/My/Files");
path.mkdirs();
if(!path.exists()) { statusText.setText("Directories do not exist");}
else recordingFile = File.createTempFile("MyRecording", ".pcm", path);
Do you have the permission set in your manifest?
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
Also, Android Studio is giving you the warning about mkDirs () because it returns a boolean indicating whether the directory was created. It's just reminding you that you never used the result. It doesn't matter.
Related
What I'm trying to achieve is to check before download if the file exists so i don't have to re-download it again. For example, i have to open for the first time this pdf from the Internet "history-of-comics.pdf", in order to do so i have to download it and open inside my app, the second time i choose to re-read it, i have to be sure that "history-of-comics.pdf" if exists inside Downloads/MyDocs, i don't have to waste resources and let the user wait to download it again. Currently the app targetSdkVersion is 29 and what i have done so far is:
Give permissions for READ_EXTERNAL_STORAGE & WRITE_EXTERNAL_STORAGE
Included in manifest android:requestLegacyExternalStorage="true" inside application tag
Download the pdf file in the MyDocs inside Downloads folder
Below is a quick sample of my code (i have commented the other combinations i have tried):
private void checkIfPdfExists(String pdfFileName) {
String uriFile = String.valueOf(getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS+File.separator+"MyDocs"+File.separator+pdfFileName+".pdf"));
File file = new File(uriFile);
//File file = new File(getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS)+"/MyDocs", pdfFileName+".pdf");
//File file = new File(Environment.DIRECTORY_DOWNLOADS+File.separatorChar+"MyDocs"+File.separatorChar+pdfFileName+".pdf");
//File file = new File(Environment.DIRECTORY_DOWNLOADS+File.separatorChar+"MyDocs", pdfFileName+".pdf");
if (file.exists() && file!=null) {
Toast.makeText(getApplicationContext(), file.getPath() + "/n exists", Toast.LENGTH_SHORT).show();
displayFromUri(Uri.parse(file.getPath()));
} else {
beginDownload("https://www.heritagestatic.com/comics/d/history-of-comics.pdf",pdfFileName);
}
}
And this is how i define the path when i download the pdf, the downloader works as it should:
DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));
request.addRequestHeader("Accept", "application/pdf");
request.setDescription(file_name);
request.setTitle("Getting your doc");
request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS,"MyDocs/"+file_name+".pdf");
I did some research before posting the question and in some threads i found that is related to Android Q, but i can't find a real solution for it. Any help would be appreciated, thanks in advance!
The solution to my problem was how i was referring to file path and the method used for download. As #blackapps mentioned that if you use "setDestinationInExternalFilesDir" to save the file, the proper way to check if the file exist is with "getExternalFilesDir", in my case:
File file = new File(getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS)+File.separator+"MyDocs"+File.separator+pdfFileName+".pdf");
I want to create a sub directory which is non-private under the Environment.DIRECTORY_PICTURES directory. I used the code shown below but of no avail. The directory is created but it remains private. I don't know where I'm wrong.
File file = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES), "MyImages");
file.mkdirs();
File f = new File(file,"Image1");
First, you have not created a file, at least in the code that is shown above. You have created a Java File object, and you created a directory, but you did not create a file for Image1, and so your directory is empty. I know of no way to force your empty directory to be picked up by anything, though you should see it if you use adb shell or DDMS to examine your device.
When you do eventually write a file to this directory, be sure to call getFD().sync() on the FileOutputStream before you close() that stream. Then, use MediaScannerConnection and its static scanFile() method to have your newly-created file be indexed by the MediaStore. Until you do this, your newly-created file will not be visible via MTP or many third-party apps.
I am developing an android application. I need to create a folder in the internal memory, but when I try to create the folder I get the error below. I am running in an emulator.
mkdir failed for /mnt/New Folder , read only file system
I have tried many paths, but still the error persists. The only folder that I am able to create is called "cache", but I cannot browse it by my file chooser activity.
Any idea where is the suitable place to create folders without any permissions?
You can achieve it by this from a Context object (like Activity).
File files_folder = getFilesDir();
File files_child = new File(files_folder, "files_child");
files_child.mkdirs();
File created_folder = getDir("custom", MODE_PRIVATE);
File f1_child = new File(created_folder, "custom_child");
f1_child.mkdirs();
The function
getFilesDir()
will get the folder data/data/yourpackagename/files in internal memory. And the function
getDir("custom", MODE_PRIVATE)
will create a folder name app_custom in your app internal folder.
Answered by Minhtdh
I guess what you call internal memory is atualy the external memory (which can be open by
file chooser activity, the real internal memory only can be open if you have rooted)
If that true, you should chek those belows:
- first, you will need the write storeage permission in Manisfest
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
- then you should use `
String path =
Environment.getExternalStorageDirectory().getAbsolutePath() +
"/yourfoldername"
`
than
mnt/yourfoldername
at last you should use mkdirs to create folder than mkdir
I have a routed device and when I do this
adb shell cat /data/misc/bluetooth/dynamic_auto_pairing.conf
it prints the content of this file.
But in my code when I write something like this, it says that the file does not exist. Well from the console I see it I know is there, but from code I can't read it. My question is what is the problem , am I missing some permission or what is the problem ? can someone provide me with some code to read the content from this file.
Thanks
File pa = new File("/data/misc/bluetooth/","dynamic_auto_pairing.conf");
//this doesn't works also
//File pa = new File("/data/misc/bluetooth","dynamic_auto_pairing.conf");
//File pa = new File("/data/misc/bluetooth/dynamic_auto_pairing.conf");
if(pa.exists()){
Log.v("tag", "does exists");
}else{
Log.v("tag", "does NOT exist");
}
If the file is on sdcard, try:
File pa = new File(Environment.getExternalStorageDirectory() + "/data/misc/bluetooth/dynamic_auto_pairing.conf");
Also try to add:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
outside <application></application> in your manifest file.
EDIT
If the file is in internal memory: Your app can read only from a special folder in internal memory. The path to that folder is returned by:
getFilesDir().getAbsolutePath()
So put the file there and read it with openFileInput().
More info:
http://developer.android.com/guide/topics/data/data-storage.html#filesInternal
From the docs for File...
public File (String dirPath, String name)
Constructs a new File using the specified directory path and file name, placing a path separator between the two.
In your code you are using...
File pa = new File("/data/misc/bluetooth/","dynamic_auto_pairing.conf");
...and because your dirPath ends with a separator "/data/misc/bluetooth/" it will result in two separators. In other words, effective path will be...
/data/misc/bluetooth//dynamic_auto_pairing.conf
Note the // after 'bluetooth`
If you are using android 6.0 or higher. You must request permission in code.
I want to create .nomedia file in the internal cache directory where I will store images and tried the following..
File dir = getCacheDir();
File output = new File(dir, ".nomedia");
boolean fileCreated = output.createNewFile();
When I try this fileCreated is false and the file doesn't get created.
If I used nomedia without a dot the file gets created but this is no use as the MediaScanner is looking if the .nomedia file exists.
I also tried this with a FileOutputStream and to write data in the file in case it was because I was only created an empty file but this doesn't work either.
Anyone have an idea why this could be failing?
Hmm, are you really sure that the file not already exists? Please note that you need to do an ls -a to see a file starting with a dot.
The documentation of File.createNewFile() says:
Returns true if the file has been
created, false if it already exists.
If the file is not created for other reasons (i.e. security), it should throw an exception.