Android app: mkdir() fails on Google Nexus 7

Question

I am trying to create a folder with mkdir() with an app on a Google Nexus 7 tablet. After that I am saving an image in that folder.

The relevant code is:

    // Create the storage directory if it does not exist
    if (!mediaStorageDir.exists()) {
        if (!mediaStorageDir.mkdir()) {
            Log.d(TAG, "Oops! Failed create "
                    + Config.IMAGE_DIRECTORY_NAME + " directory");
            return null;
        }
    }

and the log says: "Oops! Failed create userImages".

What I have tried so far:

• testing the App on a Samsung Galaxy S3 mini with Android 4.1.2 and it worked. (-> it seems to be device specific)

• Adding the permission
  < uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" >
  to the AndroidManifest.xml

• using mkdirs() instead of mkdir()

• the function

  //Check SD card state
  String state = Environment.getExternalStorageState();
  if (Environment.MEDIA_MOUNTED_READ_ONLY.equals(state) || !Environment.MEDIA_MOUNTED.equals(state)) {
      Log.e(TAG, "Error: external storage is read only or unavailable");
  } else {
      Log.d(TAG, "External storage is not read only or unavailable");
  }
  

  gives "External storage is not read only or unavailable".

My code:

AndroidManifest.xml:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="de.hbksaar.bubbles">
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>

Does anybody have a clue, why it is not possible for me to create that folder?

Answer 1

Which version of Android OS you used ? If you run on Android 6.0, it maybe due to you app donot have Storage permission, go to Settings -> Apps -> Your App -> Permissions to double check your app have Storage permission. Grant Storage permission if not granted yet.

Try to log the full path of mediaStorageDir to make sure it is a correct path on SD Card.

Also try to use mkdirs() to create non-exist parent directories.