...

app/src/main/java/com/base/pdfreader2/ui/main/MainActivity.kt

 package com.base.pdfreader2.ui.main
 
+import android.annotation.SuppressLint
 import android.app.Dialog
 import android.content.Intent
 import android.graphics.Color
@@ -34,6 +35,7 @@ import com.base.pdfreader2.ui.main.DocumentFragment.Companion.jumpDocument
 import com.base.pdfreader2.ui.pdf.PdfSelectActivity
 import com.base.pdfreader2.ui.view.DialogView.showDeleteDialog
 import com.base.pdfreader2.ui.view.DialogView.showSortDialog
+import com.base.pdfreader2.ui.view.MainDialog.showAppExitDialog
 import com.base.pdfreader2.ui.view.MainDialog.showDefaultBottomDialog
 import com.base.pdfreader2.ui.view.MainDialog.showNotificationDialog
 import com.base.pdfreader2.ui.view.MainDialog.showStoragePermission
@@ -137,6 +139,12 @@ class MainActivity : BaseActivity<ActivityMainBinding>(), MainView {
     }
 
 
+    @SuppressLint("MissingSuperCall")
+    override fun onBackPressed() {
+        LogEx.logDebug(TAG, "onBackPressed")
+        showAppExitDialog()
+    }
+
     //OnBackPressedCallback 并将 isEnabled 设置为 false 时，默认的返回键行为将被禁用。
     lateinit var callback: OnBackPressedCallback
     override fun initListener() {

app/src/main/java/com/base/pdfreader2/ui/pdf/PdfActivity.kt

@@ -92,7 +92,7 @@ class PdfActivity : BaseActivity<ActivityPdfBinding>(), PdfView {
         lifecycleScope.launch(Dispatchers.Main) {
             while (isActive) {
                 binding.progressBar.progress += 2
-                delay(Random.nextLong(30, 50))
+                delay(Random.nextLong(30, 35))
                 if (binding.progressBar.progress >= 100) {
                     binding.flLoading.visibility = View.GONE
                     break
@@ -151,7 +151,6 @@ class PdfActivity : BaseActivity<ActivityPdfBinding>(), PdfView {
             SpStringUtils.addSpString(LAST_VIEW_KEY, "${path}_/_${System.currentTimeMillis()}")
         }
 
-        showGuide()
         AdmobNativeUtils.showNativeAd(this, binding.flAd, R.layout.layout_admob_document_in)
     }
 

app/src/main/java/com/base/pdfreader2/ui/view/MainDialog.kt

@@ -18,7 +18,9 @@ import android.view.WindowManager
 import android.widget.LinearLayout
 import androidx.core.content.ContextCompat
 import com.base.pdfreader2.R
+import com.base.pdfreader2.ads.admob.AdmobNativeUtils
 import com.base.pdfreader2.bean.ConstObject.setDefault
+import com.base.pdfreader2.databinding.DialogAppExitBinding
 import com.base.pdfreader2.databinding.DialogDefaultBottomBinding
 import com.base.pdfreader2.databinding.DialogDefaultUpBinding
 import com.base.pdfreader2.databinding.DialogNotificationEnableBinding
@@ -202,4 +204,28 @@ object MainDialog {
             }
         }
     }
+
+    fun Activity.showAppExitDialog() {
+        val dialog = BottomSheetDialog(this, R.style.BottomSheetDialog)
+        val binding = DialogAppExitBinding.inflate(LayoutInflater.from(this))
+        dialog.setContentView(binding.root)
+        dialog.setCanceledOnTouchOutside(false)
+
+        dialog.show()
+
+        val parentView = binding.root.parent as View
+        val behavior = BottomSheetBehavior.from(parentView)
+        //展开
+        behavior.state = BottomSheetBehavior.STATE_EXPANDED
+
+        AdmobNativeUtils.showNativeAd(this, binding.flAd, R.layout.layout_admob_app_exit)
+
+        binding.cardNo.setOnClickListener {
+            finish()
+        }
+        binding.cardYes.setOnClickListener {
+            dialog.dismiss()
+        }
+    }
+
 }
\ No newline at end of file

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

+<?xml version="1.0" encoding="utf-8"?>
+<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:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:background="@drawable/bg_ffffff_tlr25"
+    android:orientation="vertical">
+
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="vertical"
+        app:layout_constraintTop_toTopOf="parent">
+
+        <TextView
+            android:id="@+id/tv_tip"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_gravity="center_horizontal"
+            android:layout_marginTop="28dp"
+            android:text="Are you sure want to exit the app?"
+            android:textColor="#333333"
+            android:textSize="18sp"
+            android:textStyle="bold"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toTopOf="parent"
+            tools:ignore="HardcodedText" />
+
+
+        <FrameLayout
+            android:id="@+id/fl_ad"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_marginHorizontal="16dp"
+            android:layout_marginTop="8dp"
+            android:gravity="center_horizontal"
+            tools:ignore="Autofill,HardcodedText,LabelFor,TextFields">
+
+            <ImageView
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:layout_gravity="center_horizontal"
+                android:scaleType="fitCenter"
+                android:src="@mipmap/zhanweitu"
+                tools:ignore="ContentDescription" />
+
+        </FrameLayout>
+
+        <LinearLayout
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_gravity="center_horizontal"
+            android:layout_marginTop="20dp"
+            android:layout_marginBottom="15dp"
+            android:padding="5dp">
+
+            <androidx.cardview.widget.CardView
+                android:id="@+id/card_no"
+                android:layout_width="163dp"
+                android:layout_height="48dp"
+                app:cardBackgroundColor="#f1f2f6"
+                app:cardCornerRadius="10dp"
+                app:cardElevation="0dp">
+
+                <TextView
+                    android:id="@+id/tv_no"
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:layout_gravity="center"
+                    android:gravity="center"
+                    android:text="@string/exit"
+                    android:textColor="#505050"
+                    android:textSize="18sp"
+                    tools:ignore="HardcodedText" />
+            </androidx.cardview.widget.CardView>
+
+
+            <androidx.cardview.widget.CardView
+                android:id="@+id/card_yes"
+                android:layout_width="163dp"
+                android:layout_height="48dp"
+                android:layout_marginStart="14dp"
+                app:cardBackgroundColor="#DE202A"
+                app:cardCornerRadius="10dp"
+                app:cardElevation="0dp"
+                tools:ignore="HardcodedText">
+
+                <TextView
+                    android:id="@+id/tv_yes"
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:layout_gravity="center"
+                    android:text="@string/cancel"
+                    android:textColor="@color/white"
+                    android:textSize="18sp" />
+
+            </androidx.cardview.widget.CardView>
+
+        </LinearLayout>
+
+    </LinearLayout>
+
+</androidx.constraintlayout.widget.ConstraintLayout>
\ No newline at end of file