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Android Android Data Persistence File Storage Writing to Internal Storage

Posted by Adlight Sibanda
Adlight Sibanda
5,701 Points

Writing files

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.

FileUtilities.java 
import java.io.InputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

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

    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;
  }
}

2 Answers

Steve Hunter
Steve Hunter
57,712 Points

Hi there,

You're very close indeed!! Rather than testing for .exists() == false (which is odd; if it doesn't exist does it know that?) test for that being not true:

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

I hope that helps!

Steve.

Adlight Sibanda
Adlight Sibanda
5,701 Points

Thanx Steve

seems in my code I had Capitalized: if (FileToWrite.exists() == false) { copyResult = copyFile(in, out); }

Instead of:

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

and it passed .... :-}

Steve Hunter
Steve Hunter
57,712 Points

Great work - glad you got it sorted out. :-)

Steve.

Alwin Lazar V
Alwin Lazar V
5,267 Points
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

[MOD: edited code block]

Steve Hunter
Steve Hunter
57,712 Points

Good work.

As in the above post, an alternative test to fileToWrite.exists() == false, you can use !fileToWrite.exists() - it amounts to the same thing.

Steve.