Code improvements

* Replace unchecked casts with checked casts
 * remove Utility.finViewById
 * Fix return activity checking
 * Create UserAction enum
 * Fix typos
 * Add instrumented test for error info
 * ErrorInfo make fields final
 * Log exception using logger
 * Add inherited annotations
 * Resolve deprecation warnings
 * Remove unused methods from utility
 * Reformat code
 * Remove unused methods from Utility and improve getFileExt
 * Create OnScrollBelowItemsListener

app/src/androidTest/java/org/schabi/newpipe/report/ErrorInfoTest.java

@@ -0,0 +1,37 @@
+package org.schabi.newpipe.report;
+
+import android.os.Parcel;
+import android.support.test.filters.LargeTest;
+import android.support.test.runner.AndroidJUnit4;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.schabi.newpipe.R;
+import org.schabi.newpipe.report.ErrorActivity.ErrorInfo;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * Instrumented tests for {@link ErrorInfo}
+ */
+@RunWith(AndroidJUnit4.class)
+@LargeTest
+public class ErrorInfoTest {
+
+    @Test
+    public void errorInfo_testParcelable() {
+        ErrorInfo info = ErrorInfo.make(UserAction.USER_REPORT, "youtube", "request", R.string.general_error);
+        // Obtain a Parcel object and write the parcelable object to it:
+        Parcel parcel = Parcel.obtain();
+        info.writeToParcel(parcel, 0);
+        parcel.setDataPosition(0);
+        ErrorInfo infoFromParcel = ErrorInfo.CREATOR.createFromParcel(parcel);
+
+        assertEquals(UserAction.USER_REPORT, infoFromParcel.userAction);
+        assertEquals("youtube", infoFromParcel.serviceName);
+        assertEquals("request", infoFromParcel.request);
+        assertEquals(R.string.general_error, infoFromParcel.message);
+
+        parcel.recycle();
+    }
+}