How to display a local file in the Android WebView

For some reason WebView is not displaying local files found on sdcard or in other directories of an Android phone. It was doing so prior to the official 1.0 SDK release, but not anymore.
There was another way to display local files - by overriding WebViewClient.shouldOverrideUrlLoading, but since 1.0 SDK it's gone.

Right now community agrees that a relatively easy way to make WebView display local files is through a custom ContentProvider.

It's not quite obvious what needs to be overridden for this specific task. I couldn't find a complete example online. So I decided to share mine.

There are 2 steps

1. Create new class that extends ContentProvider and override essentially 1 method openFile. Method onCreate can be empty returning true and the rest can just throw UnsupportedOperationException.
2. Add a provider entry to AndroidManifest.xml.
   

Provider implementation

Note, that method constructUri is just a utility method that can be used to construct provider specific URI out of a file path.

package com.tourizo.android.content;

import java.io.*;

import android.content.*;
import android.database.*;
import android.net.*;
import android.os.*;

public class LocalFileContentProvider extends ContentProvider {
   private static final String URI_PREFIX = "content://com.tourizo.android.localfile";

   public static String constructUri(String url) {
       Uri uri = Uri.parse(url);
       return uri.isAbsolute() ? url : URI_PREFIX + url;
   }

   @Override
   public ParcelFileDescriptor openFile(Uri uri, String mode) throws FileNotFoundException {
       File file = new File(uri.getPath());
       ParcelFileDescriptor parcel = ParcelFileDescriptor.open(file, ParcelFileDescriptor.MODE_READ_ONLY);
       return parcel;
   }

   @Override
   public boolean onCreate() {
       return true;
   }

   @Override
   public int delete(Uri uri, String s, String[] as) {
       throw new UnsupportedOperationException("Not supported by this provider");
   }

   @Override
   public String getType(Uri uri) {
       throw new UnsupportedOperationException("Not supported by this provider");
   }

   @Override
   public Uri insert(Uri uri, ContentValues contentvalues) {
       throw new UnsupportedOperationException("Not supported by this provider");
   }

   @Override
   public Cursor query(Uri uri, String[] as, String s, String[] as1, String s1) {
       throw new UnsupportedOperationException("Not supported by this provider");
   }

   @Override
   public int update(Uri uri, ContentValues contentvalues, String s, String[] as) {
       throw new UnsupportedOperationException("Not supported by this provider");
   }

}

AndroidManifest.xml entry under application tag

        <provider android:name=".content.LocalFileContentProvider"
          android:authorities="com.tourizo.android.localfile"
      />

I hope this was helpful.

Happy hacking! :)