优化

app/src/main/java/com/common/weikaiyun/adapter/CustomFragmentPagerAdapter.kt

@@ -0,0 +1,39 @@
+package com.common.weikaiyun.adapter
+
+import android.annotation.SuppressLint
+import android.util.SparseArray
+import android.view.ViewGroup
+import androidx.fragment.app.Fragment
+import androidx.fragment.app.FragmentManager
+import androidx.fragment.app.FragmentPagerAdapter
+
+/**
+ * This class is FragmentPagerAdapter where all the fragments are in an array and you can access to them later.
+ * @property mFragments the list of fragments
+ * 适用viewpager
+ */
+@SuppressLint("WrongConstant")
+abstract class CustomFragmentPagerAdapter(fm: FragmentManager) : FragmentPagerAdapter(fm, BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT) {
+
+    val mFragments = SparseArray<Fragment>()
+
+    override fun instantiateItem(container: ViewGroup, position: Int): Any {
+        val fragment = super.instantiateItem(container, position) as Fragment
+        mFragments.put(position, fragment)
+        return fragment
+    }
+
+    override fun destroyItem(container: ViewGroup, position: Int, `object`: Any) {
+        mFragments.remove(position)
+        super.destroyItem(container, position, `object`)
+    }
+
+    /**
+     * Returns the instance of the fragment if it is created, null otherwise.
+     */
+    fun getFragment(position: Int): Fragment? {
+        return if (mFragments.size() == 0) {
+            null
+        } else mFragments.get(position)
+    }
+}

app/src/main/java/com/common/weikaiyun/adapter/CustomFragmentStateAdapter.kt

@@ -4,6 +4,7 @@ import androidx.viewpager2.adapter.FragmentStateAdapter
 import com.weikaiyun.fragmentation.SupportActivity
 import com.weikaiyun.fragmentation.SupportFragment
 
+//适用viewpager2
 
 class CustomFragmentStateAdapter(
     activity: SupportActivity,