Disable zero rating to gallery

app/src/main/java/com/hippo/ehviewer/widget/GalleryRatingBar.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright 2014-2016 Hippo Seven
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.hippo.ehviewer.widget;
+
+import android.content.Context;
+import android.graphics.Canvas;
+import android.support.v7.widget.AppCompatRatingBar;
+import android.util.AttributeSet;
+import android.widget.RatingBar;
+
+public class GalleryRatingBar extends AppCompatRatingBar
+        implements RatingBar.OnRatingBarChangeListener {
+
+    private OnUserRateListener mListener;
+
+    public GalleryRatingBar(Context context) {
+        super(context);
+        init();
+    }
+
+    public GalleryRatingBar(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        init();
+    }
+
+    public GalleryRatingBar(Context context, AttributeSet attrs,
+            int defStyle) {
+        super(context, attrs, defStyle);
+        init();
+    }
+
+    private void init() {
+        setOnRatingBarChangeListener(this);
+    }
+
+    @Override
+    protected void onDraw(Canvas canvas) {
+        super.onDraw(canvas);
+
+        if (mListener != null) {
+            mListener.onUserRate(getRating());
+        }
+    }
+
+    public void setOnUserRateListener(OnUserRateListener l) {
+        mListener = l;
+    }
+
+    @Override
+    public void onRatingChanged(RatingBar ratingBar, float rating, boolean fromUser) {
+        if (rating <= 0.0f) {
+            setRating(0.5f);
+        }
+    }
+
+    public interface OnUserRateListener {
+        void onUserRate(float rating);
+    }
+}