Avoid throwing on invalid resource ids.

Fixes #413

library/src/androidTest/java/com/bumptech/glide/load/model/stream/ResourceLoaderTest.java

 package com.bumptech.glide.load.model.stream;
 
+import static com.google.common.truth.Truth.assertThat;
 import static org.mockito.Matchers.any;
 import static org.mockito.Matchers.anyInt;
 import static org.mockito.Matchers.eq;
-import static org.mockito.Mockito.atLeastOnce;
-import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.verify;
-import static org.mockito.Mockito.when;
 
 import android.net.Uri;
 
 import com.bumptech.glide.load.model.ModelLoader;
 
+import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
 import org.robolectric.Robolectric;
 import org.robolectric.RobolectricTestRunner;
 import org.robolectric.annotation.Config;
@@ -27,17 +29,27 @@ import java.io.InputStream;
 @Config(manifest = Config.NONE, emulateSdk = 18)
 public class ResourceLoaderTest {
 
+    @Mock ModelLoader<Uri, InputStream> streamUriLoader;
+    private StreamResourceLoader resourceLoader;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+        resourceLoader = new StreamResourceLoader(Robolectric.application, streamUriLoader);
+    }
+
     @Test
     public void testCanHandleId() {
-        ModelLoader<Uri, InputStream> streamUriLoader = mock(ModelLoader.class);
-        when(streamUriLoader.getResourceFetcher(any(Uri.class), anyInt(), anyInt())).thenReturn(null);
-
         int id = android.R.drawable.star_off;
-
-        StreamResourceLoader resourceLoader = new StreamResourceLoader(Robolectric.application, streamUriLoader);
         resourceLoader.getResourceFetcher(id, 0, 0);
 
         Uri contentUri = Uri.parse("android.resource://android/drawable/star_off");
-        verify(streamUriLoader, atLeastOnce()).getResourceFetcher(eq(contentUri), anyInt(), anyInt());
+        verify(streamUriLoader).getResourceFetcher(eq(contentUri), anyInt(), anyInt());
+    }
+
+    @Test
+    public void testDoesNotThrowOnInvalidOrMissingId() {
+        assertThat(resourceLoader.getResourceFetcher(1234, 0, 0)).isNull();
+        verify(streamUriLoader, never()).getResourceFetcher(any(Uri.class), anyInt(), anyInt());
     }
 }

library/src/main/java/com/bumptech/glide/load/model/ResourceLoader.java

@@ -4,6 +4,7 @@ import android.content.ContentResolver;
 import android.content.Context;
 import android.content.res.Resources;
 import android.net.Uri;
+import android.util.Log;
 
 import com.bumptech.glide.load.data.DataFetcher;
 
@@ -14,6 +15,7 @@ import com.bumptech.glide.load.data.DataFetcher;
  * @param <T> The type of data that will be loaded for the given android resource.
  */
 public class ResourceLoader<T> implements ModelLoader<Integer, T> {
+    private static final String TAG = "ResourceLoader";
 
     private final ModelLoader<Uri, T> uriLoader;
     private final Resources resources;
@@ -29,11 +31,22 @@ public class ResourceLoader<T> implements ModelLoader<Integer, T> {
 
     @Override
     public DataFetcher<T> getResourceFetcher(Integer model, int width, int height) {
-        Uri uri = Uri.parse(ContentResolver.SCHEME_ANDROID_RESOURCE + "://"
-                + resources.getResourcePackageName(model) + '/'
-                + resources.getResourceTypeName(model) + '/'
-                + resources.getResourceEntryName(model));
-
-        return uriLoader.getResourceFetcher(uri, width, height);
+        Uri uri = null;
+        try {
+          uri = Uri.parse(ContentResolver.SCHEME_ANDROID_RESOURCE + "://"
+                  + resources.getResourcePackageName(model) + '/'
+                  + resources.getResourceTypeName(model) + '/'
+                  + resources.getResourceEntryName(model));
+        } catch (Resources.NotFoundException e) {
+            if (Log.isLoggable(TAG, Log.WARN)) {
+                Log.w(TAG, "Received invalid resource id: " + model, e);
+            }
+        }
+
+        if (uri != null) {
+            return uriLoader.getResourceFetcher(uri, width, height);
+        } else {
+            return null;
+        }
     }
 }

library/src/main/java/com/bumptech/glide/request/GenericRequest.java

@@ -417,7 +417,7 @@ public final class GenericRequest<A, T, Z, R> implements Request, SizeReadyCallb
         final DataFetcher<T> dataFetcher = modelLoader.getResourceFetcher(model, width, height);
 
         if (dataFetcher == null) {
-            onException(new Exception("Got null fetcher from model loader"));
+            onException(new Exception("Failed to load model: " + model));
             return;
         }
         ResourceTranscoder<Z, R> transcoder = loadProvider.getTranscoder();