Fix a bug so when user clicks the SeekBarPanel, the x coordinate with the correct x-offset is sent to SeekBar.

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

@@ -21,6 +21,7 @@ import android.graphics.Rect;
 import android.support.annotation.NonNull;
 import android.util.AttributeSet;
 import android.view.MotionEvent;
+import android.view.View;
 import android.widget.LinearLayout;
 import android.widget.SeekBar;
 
@@ -54,8 +55,9 @@ public class SeekBarPanel extends LinearLayout {
         if (mSeekBar == null) {
             return super.onTouchEvent(event);
         } else {
-            final float offsetX = -mSeekBar.getLeft();
-            final float offsetY = -mSeekBar.getTop();
+            View containingView = (View) mSeekBar.getParent();
+            final float offsetX = -(containingView.getLeft() + mSeekBar.getLeft());
+            final float offsetY = -(containingView.getTop() + mSeekBar.getTop());
             event.offsetLocation(offsetX, offsetY);
             mSeekBar.onTouchEvent(event);
             event.offsetLocation(-offsetX, -offsetY);