feat: 添加示例代码

app/src/main/AndroidManifest.xml

@@ -27,6 +27,7 @@
         <activity android:name=".compat.ImmutableCompatActivity" />
         <activity android:name=".systembar.SystemBarBasicActivity" />
         <activity android:name=".systembar.SystemBarRestoreActivity" />
+        <activity android:name=".systembar.SystemBarVp2Activity" />
     </application>
 
 </manifest>

app/src/main/kotlin/com/xiaocydx/insets/sample/MainActivity.kt

@@ -10,6 +10,7 @@ import com.xiaocydx.insets.sample.compat.ImmutableCompatActivity
 import com.xiaocydx.insets.sample.databinding.ActivityMainBinding
 import com.xiaocydx.insets.sample.systembar.SystemBarBasicActivity
 import com.xiaocydx.insets.sample.systembar.SystemBarRestoreActivity
+import com.xiaocydx.insets.sample.systembar.SystemBarVp2Activity
 
 /**
  * @author xcc
@@ -29,6 +30,7 @@ class MainActivity : AppCompatActivity() {
             btnImmutableCompat.onClick { startActivity<ImmutableCompatActivity>() }
             btnSystemBarBasic.onClick { startActivity<SystemBarBasicActivity>() }
             btnSystemBarRestore.onClick { startActivity<SystemBarRestoreActivity>() }
+            btnSystemBarVp2.onClick { startActivity<SystemBarVp2Activity>() }
         }.root
 
     private inline fun <reified T : Activity> startActivity() {

app/src/main/kotlin/com/xiaocydx/insets/sample/systembar/SystemBarVp2Activity.kt

@@ -0,0 +1,107 @@
+@file:SuppressLint("SetTextI18n")
+
+package com.xiaocydx.insets.sample.systembar
+
+import android.annotation.SuppressLint
+import android.os.Bundle
+import androidx.appcompat.app.AppCompatActivity
+import androidx.core.os.bundleOf
+import androidx.core.view.updatePadding
+import androidx.fragment.app.Fragment
+import androidx.fragment.app.FragmentActivity
+import androidx.viewpager2.adapter.FragmentStateAdapter
+import androidx.viewpager2.widget.ViewPager2
+import com.xiaocydx.insets.doOnApplyWindowInsets
+import com.xiaocydx.insets.sample.databinding.ActivitySystemBarVp2Binding
+import com.xiaocydx.insets.sample.databinding.LayoutBaseBinding
+import com.xiaocydx.insets.sample.onClick
+import com.xiaocydx.insets.statusBarHeight
+import com.xiaocydx.insets.systembar.EdgeToEdge
+import com.xiaocydx.insets.systembar.SystemBar
+
+/**
+ * 在[ViewPager2]场景下使用[SystemBar]：
+ * 1. [FragmentStateAdapter]构建的[Fragment]不要实现[SystemBar]。
+ * 2. [ViewPager2]所在的[FragmentActivity]或[Fragment]实现[SystemBar]。
+ * 3. 选中[Fragment]或者滚动停止时，应用`ViewPager2.currentItem`对应的配置。
+ *
+ * @author xcc
+ * @date 2023/12/29
+ */
+class SystemBarVp2Activity : AppCompatActivity(), SystemBar, SystemBar.Host {
+    private val controller = systemBarController {
+        // PageFragment自行处理状态栏Insets
+        statusBarEdgeToEdge = EdgeToEdge.Enabled
+    }
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(contentView())
+    }
+
+    private fun contentView() = ActivitySystemBarVp2Binding
+        .inflate(layoutInflater).apply {
+            val pageAdapter = PageAdapter(this@SystemBarVp2Activity)
+            viewPager2.adapter = pageAdapter
+            viewPager2.registerOnPageChangeCallback(object : ViewPager2.OnPageChangeCallback() {
+                override fun onPageSelected(position: Int) {
+                    val page = pageAdapter.pages[position]
+                    controller.navigationBarColor = page.navigationBarColor
+                    controller.isAppearanceLightNavigationBar = page.isAppearanceLightNavigationBar
+                }
+            })
+        }.root
+
+    private class PageAdapter(
+        fragmentActivity: FragmentActivity
+    ) : FragmentStateAdapter(fragmentActivity) {
+        val pages = Page.values()
+
+        override fun getItemCount() = pages.size
+
+        override fun createFragment(position: Int): Fragment {
+            return PageFragment.newInstance(pages[position].ordinal)
+        }
+    }
+}
+
+enum class Page(
+    val navigationBarColor: Int,
+    val isAppearanceLightNavigationBar: Boolean
+) {
+    A(0xFFBABBC4.toInt(), true),
+    B(0xFF496291.toInt(), false),
+    C(0xFFD0CE85.toInt(), true)
+}
+
+class PageFragment : BaseFragment() {
+
+    override fun LayoutBaseBinding.initView() {
+        val ordinal = requireNotNull(arguments?.getInt(KEY_ORDINAL))
+        val page = Page.values()[ordinal]
+        root.setBackgroundColor(0xFFAABBC4.toInt())
+        root.onClick { requireActivity().addFragment<NotPageFragment>() }
+        root.doOnApplyWindowInsets { view, insets, initialState ->
+            view.updatePadding(top = initialState.paddings.top + insets.statusBarHeight)
+        }
+        tvCenter.text = "PageFragment${page.name}\n\n点击添加NotPageFragment"
+    }
+
+    companion object {
+        private const val KEY_ORDINAL = "KEY_ORDINAL"
+
+        fun newInstance(ordinal: Int) = PageFragment()
+            .apply { arguments = bundleOf(KEY_ORDINAL to ordinal) }
+    }
+}
+
+/**
+ * 添加在[ViewPager2]上面的[Fragment]，仍然可以实现[SystemBar]
+ */
+class NotPageFragment : BaseFragment(), SystemBar {
+
+    override fun LayoutBaseBinding.initView() {
+        root.setBackgroundColor(0xFFC4B3BB.toInt())
+        tvCenter.text = "NotPageFragment"
+    }
+}

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

@@ -46,4 +46,12 @@
         android:layout_marginBottom="5dp"
         android:text="SystemBarRestore"
         android:textAllCaps="false" />
+
+    <Button
+        android:id="@+id/btnSystemBarVp2"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginBottom="5dp"
+        android:text="SystemBarVp2"
+        android:textAllCaps="false" />
 </LinearLayout>

app/src/main/res/layout/activity_system_bar_vp2.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.viewpager2.widget.ViewPager2 xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/viewPager2"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent" />