adding a page counter at the pdf viewer

app/src/main/kotlin/com/simplemobiletools/filemanager/pro/activities/PDFViewerActivity.kt

@@ -8,8 +8,9 @@ import android.print.PrintAttributes
 import android.print.PrintManager
 import android.view.View
 import android.view.WindowManager
-import android.widget.RelativeLayout
+import androidx.constraintlayout.widget.ConstraintLayout
 import androidx.viewpager2.widget.ViewPager2
+import androidx.viewpager2.widget.ViewPager2.OnPageChangeCallback
 import com.simplemobiletools.commons.extensions.*
 import com.simplemobiletools.commons.helpers.REAL_FILE_PATH
 import com.simplemobiletools.commons.helpers.isPiePlus
@@ -58,7 +59,6 @@ class PDFViewerActivity : SimpleActivity() {
     }
 
     private fun setupMenu() {
-        (pdf_viewer_appbar.layoutParams as RelativeLayout.LayoutParams).topMargin = statusBarHeight
         pdf_viewer_toolbar.menu.apply {
             findItem(R.id.menu_print).isVisible = realFilePath.isNotEmpty()
             findItem(R.id.menu_print).setOnMenuItemClickListener {
@@ -71,20 +71,29 @@ class PDFViewerActivity : SimpleActivity() {
             finish()
         }
 
+        setupViewOffsets()
+        val primaryColor = getProperPrimaryColor()
+        page_counter.background?.applyColorFilter(primaryColor)
+        page_counter.setTextColor(primaryColor.getContrastColor())
+    }
+
+    override fun onConfigurationChanged(newConfig: Configuration) {
+        super.onConfigurationChanged(newConfig)
+        setupViewOffsets()
+    }
+
+    private fun setupViewOffsets() {
+        val pageCounterMargin = resources.getDimension(R.dimen.normal_margin).toInt()
+        (pdf_viewer_appbar.layoutParams as ConstraintLayout.LayoutParams).topMargin = statusBarHeight
         if (!portrait && navigationBarOnSide && navigationBarWidth > 0) {
             pdf_viewer_appbar.setPadding(0, 0, navigationBarWidth, 0)
         } else {
             pdf_viewer_appbar.setPadding(0, 0, 0, 0)
         }
-    }
 
-    override fun onConfigurationChanged(newConfig: Configuration) {
+        (page_counter.layoutParams as ConstraintLayout.LayoutParams).apply {
-        super.onConfigurationChanged(newConfig)
+            rightMargin = navigationBarWidth + pageCounterMargin
-        (pdf_viewer_appbar.layoutParams as RelativeLayout.LayoutParams).topMargin = statusBarHeight
+            bottomMargin = navigationBarHeight + pageCounterMargin
-        if (!portrait && navigationBarOnSide && navigationBarWidth > 0) {
-            pdf_viewer_appbar.setPadding(0, 0, navigationBarWidth, 0)
-        } else {
-            pdf_viewer_appbar.setPadding(0, 0, 0, 0)
         }
     }
 
@@ -103,6 +112,14 @@ class PDFViewerActivity : SimpleActivity() {
 
         pdf_viewer.orientation = ViewPager2.ORIENTATION_VERTICAL
         pdf_viewer.adapter = PDFPagerAdapter(this, clickListener, errorHandler, uri.toString(), getProperBackgroundColor())
+        pdf_viewer.registerOnPageChangeCallback(object : OnPageChangeCallback() {
+            override fun onPageSelected(position: Int) {
+                updatePageCounter(position)
+            }
+        })
+
+        updatePageCounter(0)
+        page_counter.beVisible()
 
         showSystemUI(true)
 
@@ -112,6 +129,10 @@ class PDFViewerActivity : SimpleActivity() {
         }
     }
 
+    private fun updatePageCounter(position: Int) {
+        page_counter.text = "${position + 1} / ${pdf_viewer.adapter?.itemCount}"
+    }
+
     private fun printText() {
         val adapter = PdfDocumentAdapter(this, realFilePath)
 
@@ -131,6 +152,7 @@ class PDFViewerActivity : SimpleActivity() {
             showSystemUI(true)
         }
 
+        page_counter.animate().alpha(newAlpha).start()
         top_shadow.animate().alpha(newAlpha).start()
         pdf_viewer_appbar.animate().alpha(newAlpha).withStartAction {
             if (newAlpha == 1f) {

app/src/main/res/layout/activity_pdf_viewer.xml

@@ -1,9 +1,10 @@
 <?xml version="1.0" encoding="utf-8"?>
-<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
     android:id="@+id/pdf_viewer_wrapper"
     android:layout_width="match_parent"
-    android:layout_height="wrap_content"
+    android:layout_height="match_parent"
     app:layout_behavior="@string/appbar_scrolling_view_behavior">
 
     <androidx.viewpager2.widget.ViewPager2
@@ -15,18 +16,28 @@
         android:id="@+id/top_shadow"
         android:layout_width="match_parent"
         android:layout_height="@dimen/top_shadow_height"
-        android:layout_alignParentTop="true"
         android:background="@drawable/gradient_background_flipped"
-        android:contentDescription="@null" />
+        android:contentDescription="@null"
+        app:layout_constraintTop_toTopOf="parent" />
+
+    <TextView
+        android:id="@+id/page_counter"
+        style="@style/ColoredButtonStyle"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:visibility="gone"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        tools:text="1/3" />
 
     <com.google.android.material.appbar.AppBarLayout
         android:id="@+id/pdf_viewer_appbar"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
-        android:layout_alignParentTop="true"
         android:background="@android:color/transparent"
         android:elevation="0dp"
-        app:elevation="0dp">
+        app:elevation="0dp"
+        app:layout_constraintTop_toTopOf="parent">
 
         <com.google.android.material.appbar.MaterialToolbar
             android:id="@+id/pdf_viewer_toolbar"
@@ -36,4 +47,4 @@
             app:navigationIcon="@drawable/ic_arrow_left_vector" />
 
     </com.google.android.material.appbar.AppBarLayout>
-</RelativeLayout>
+</androidx.constraintlayout.widget.ConstraintLayout>