android find external folders through mnt
<p>Let me get this out of the way; I am a beginner to java, I research the code I need and try to learn it while using it in my app.</p>

<p>I am currently stuck, not really sure how I can continue, ANY help is greatly appreciated.
I am trying to look in the /mnt/ folder for any folder with 'ext' or 'sd' in the file name. This is what I have so far, it gets me a null pointer exception but I don't know what variable is null.</p>

<pre><code>public class MainActivity extends Activity
{
    static File[] dirs;
    @Override
    public void onCreate(Bundle savedInstanceState)
        {
        this.requestWindowFeature(Window.FEATURE_NO_TITLE);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        findMnt("/mnt/");
        AlertDialog builder = new AlertDialog.Builder(this).setTitle("AppName").setMessage(dirs[0].getPath()).setNeutralButton("Close", null).show();
        AlertDialog builder2 = new AlertDialog.Builder(this).setTitle("AppName").setMessage(dirs[1].getPath()).setNeutralButton("Close", null).show();
}
    public static void findMnt(String path) {
        File file = new File(path);
        if(file.exists()){
            File[] list = file.listFiles();
            for(int i=0; i&lt;list.length; i++) {
                if(list[i].isDirectory()) {
                    if(list[i].getPath().contains("sd") || list[i].getPath().contains("ext")){
                        for(int b=0; b&lt;list.length; b++){
                            dirs[b] = new File(list[i].getPath());
                        }
                    }
                }
            }
        }
    }
</code></pre>
