Add SliderPanel to enlarge Slider touch range

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

@@ -0,0 +1,71 @@
+/*
+ * Copyright 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.support.annotation.NonNull;
+import android.util.AttributeSet;
+import android.view.MotionEvent;
+import android.view.View;
+import android.widget.LinearLayout;
+
+import com.hippo.widget.Slider;
+
+public class SliderPanel extends LinearLayout {
+
+    private Slider mSlider;
+
+    public SliderPanel(Context context) {
+        super(context);
+    }
+
+    public SliderPanel(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    public SliderPanel(Context context, AttributeSet attrs, int defStyleAttr) {
+        super(context, attrs, defStyleAttr);
+    }
+
+    @Override
+    public void onViewAdded(View child) {
+        if (child instanceof Slider) {
+            mSlider = (Slider) child;
+        }
+    }
+
+    @Override
+    public void onViewRemoved(View child) {
+        if (child == mSlider) {
+            mSlider = null;
+        }
+    }
+
+    @Override
+    public boolean onTouchEvent(@NonNull MotionEvent event) {
+        if (mSlider == null) {
+            return super.onTouchEvent(event);
+        } else {
+            final float offsetX = -mSlider.getLeft();
+            final float offsetY = -mSlider.getTop();
+            event.offsetLocation(offsetX, offsetY);
+            mSlider.onTouchEvent(event);
+            event.offsetLocation(-offsetX, -offsetY);
+            return true;
+        }
+    }
+}