[App] Add basic about text

Author: ViliusSutkus89

application/app/src/main/java/com/viliussutkus89/android/pdf2htmlex/application/AboutActivity.java

@@ -2,6 +2,7 @@
 
 import android.content.Intent;
 import android.os.Bundle;
+import android.widget.TextView;
 
 import androidx.appcompat.app.ActionBar;
 import androidx.appcompat.app.AppCompatActivity;
@@ -23,6 +24,9 @@ protected void onCreate(Bundle savedInstanceState) {
             actionBar.setDisplayShowHomeEnabled(true);
         }
 
+        TextView versionView = findViewById(R.id.about_version);
+        versionView.setText(BuildConfig.VERSION_NAME);
+
         findViewById(R.id.button_licenses).setOnClickListener(view -> startActivity(new Intent(this, OssLicensesMenuActivity.class)));
     }
 }

application/app/src/main/res/layout/activity_about.xml

@@ -16,7 +16,26 @@
         android:layout_height="match_parent"
         android:gravity="center"
         android:orientation="vertical">
+        <LinearLayout
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content">
+            <TextView
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:text="@string/about_version" />
+            <TextView
+                android:id="@+id/about_version"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content" />
+        </LinearLayout>
 
+        <TextView
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:gravity="center"
+            android:text="@string/about_text"
+            android:singleLine="false"
+            android:autoLink="web" />
         <Button
             android:id="@+id/button_licenses"
             android:layout_width="wrap_content"

application/app/src/main/res/values/strings.xml

@@ -23,4 +23,14 @@
     <string name="error_share_failed">Failed to share HTML document!</string>
     <string name="error_save_failed">Failed to save HTML document!</string>
     <string name="save_successful">HTML document saved.</string>
+
+    <string name="about_version">pdf2htmlEX-Android v</string>
+    <string name="about_text">
+        https://github.com/ViliusSutkus89/pdf2htmlEX-Android<br/>\n<br/>\n
+
+        Android port of pdf2htmlEX<br/>\n
+        https://github.com/pdf2htmlEX/pdf2htmlEX<br/>\n<br/>\n
+
+        Convert PDF to HTML without losing text or format
+    </string>
 </resources>