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Android Android Data Persistence File Storage Writing to Internal Storage

Refael Ozeri
Refael Ozeri
18,274 Points

file storage code challenge

can't seem to figure this one out, "The following code is similar to what you just wrote. Modify this code to only write the file if it does not already exist. Hint: Use the method from the File class that checks to see if a file exists or not."

public class FileUtilities {

  public static boolean copyResult;

  public static void saveAssetImage(Context context, String assetName) {
    File fileToWrite = new File(context.getFilesDir(), assetName);
    AssetManager assetManager = context.getAssets();

    try {
      InputStream in = assetManager.open(assetName);
      FileOutputStream out = new FileOutputStream(fileToWrite);
      copyResult = copyFile(in, out);
    } catch(FileNotFoundException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }

  private static boolean copyFile(InputStream in, FileOutputStream out) {
    // Copy magic intentionally omitted
    return true;
  }
}

what am I missing here?

Refael Ozeri
Refael Ozeri
18,274 Points

Nevermind, solved it!

if anyone else gets stuck in this one, the answer is :

if (fileToWrite.exists() == false) { copyResult = copyFile(in, out); }

4 Answers

Harry James
Harry James
14,780 Points

Glad to hear you got it fixed!

I'll mark this post as resolved now so that anyone else browsing this topic will know that this question has been answered :)

Refael Ozeri
Refael Ozeri
18,274 Points

Good idea, thank you :)

Anthony Attard
Anthony Attard
43,915 Points

A more concise option. if (! fileToWrite.exists()) { copyResult = copyFile(in, out); }

Nancy Melucci
PLUS
Nancy Melucci
Courses Plus Student 36,143 Points

If anyone is out there, the code posted above is NOT working for me. I am getting this error:

./FileUtilities.java:28: error: cannot find symbol if (fileToWrite.exists() == false) { copyResult = copyFile(in, out); } ^ symbol: variable fileToWrite location: class FileUtilities 1 error

Posting my code below.

public class FileUtilities {

  public static boolean copyResult;

  public static void saveAssetImage(Context context, String assetName) {
    File fileToWrite = new File(context.getFilesDir(), assetName);
    AssetManager assetManager = context.getAssets();

    try {
      InputStream in = assetManager.open(assetName);
      FileOutputStream out = new FileOutputStream(fileToWrite);
      copyResult = copyFile(in, out);
    } catch(FileNotFoundException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }

  private static boolean copyFile(InputStream in, FileOutputStream out) {
    // Copy magic intentionally omitted
     byte[] buffer = new byte[1024];
        int read;
    if (fileToWrite.exists() == false) { copyResult = copyFile(in, out); }

  }
}

Thanks.

Harry James
Harry James
14,780 Points

Hey Nancy!

fileToWrite is out of scope in that method, meaning you're unable to access it. Therefore, we need a different method of only running the copyFile() method when the fileToWrite does not exist.

Hint: Take a look at where you're calling the method from - can you run some sort of check to only call the method when this condition passes?

Alwin Lazar V
Alwin Lazar V
5,267 Points

I have solved and it works for me

public class FileUtilities {

public static boolean copyResult;

public static void saveAssetImage(Context context, String assetName) {

File fileToWrite = new File(context.getFilesDir(), assetName);
AssetManager assetManager = context.getAssets();
try {
  InputStream in = assetManager.open(assetName);
  FileOutputStream out = new FileOutputStream(fileToWrite);

// here I changed
if (fileToWrite.exists() == false) { copyResult = copyFile(in, out); }
} catch(FileNotFoundException e) {
  e.printStackTrace();
} catch (IOException e) {
  e.printStackTrace();
}

}

private static boolean copyFile(InputStream in, FileOutputStream out) { // Copy magic intentionally omitted return true; } }

Happy coding

You saved me a whole lot of time, Thank You