Fix stickyHeader flash when call notifyDataSetChange.

app/src/main/java/pokercc/android/expandablerecyclerview/sample/changeadapter/ChangeAdapterActivity.kt

@@ -1,6 +1,7 @@
 package pokercc.android.expandablerecyclerview.sample.changeadapter
 
 import android.animation.ObjectAnimator
+import android.annotation.SuppressLint
 import android.content.Context
 import android.content.Intent
 import android.os.Bundle
@@ -28,7 +29,7 @@ class ChangeAdapterActivity : AppCompatActivity() {
  override fun onCreate(savedInstanceState: Bundle?) {
  super.onCreate(savedInstanceState)
  setContentView(binding.root)
- binding.recyclerView.adapter = CountAdapter(3, 2)
+ binding.recyclerView.adapter = CountAdapter(30, 5)
  binding.recyclerView.layoutManager = LinearLayoutManager(this)
  binding.changeAdapter.setOnClickListener {
  binding.recyclerView.adapter = CountAdapter()
@@ -51,8 +52,8 @@ private class CountAdapter(
 ) : ExpandableAdapter<ExpandableAdapter.ViewHolder>() {
 
  fun setNewData() {
- groupCount = Random.nextInt(1, 10)
- childCount = Random.nextInt(2, 10)
+ groupCount = Random.nextInt(5, 10)
+ childCount = Random.nextInt(3, 10)
  notifyDataSetChanged()
  }
 
@@ -84,6 +85,7 @@ private class CountAdapter(
  }
  }
 
+ @SuppressLint("SetTextI18n")
  override fun onBindGroupViewHolder(
  holder: ExpandableAdapter.ViewHolder,
  groupPosition: Int,
@@ -92,7 +94,7 @@ private class CountAdapter(
  ) {
  if (payloads.isEmpty()) {
  (holder as? ParentVH)?.apply {
- binding.titleText.text = (groupPosition + 1).toString()
+ binding.titleText.text = "Group "+(groupPosition + 1).toString()
  binding.arrowImage.rotation = if (expand) 0f else -90.0f
  }
  }

build.gradle

@@ -7,7 +7,7 @@ buildscript {
  jcenter()
  }
  dependencies {
- classpath "com.android.tools.build:gradle:4.1.1"
+ classpath 'com.android.tools.build:gradle:7.0.3'
  classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
  classpath 'com.jfrog.bintray.gradle:gradle-bintray-plugin:1.8.5'
  classpath 'com.github.dcendents:android-maven-gradle-plugin:2.1'

expandableRecyclerView/build.gradle

@@ -1,7 +1,7 @@
 apply plugin: 'com.android.library'
 apply plugin: 'kotlin-android'
 apply from: rootProject.file("config.gradle.kt")
-apply from: rootProject.file("bintray.gradle")
+//apply from: rootProject.file("bintray.gradle")
 
 android {
  testOptions {

expandableRecyclerView/src/main/java/pokercc/android/expandablerecyclerview/StickyHeader.kt

@@ -13,6 +13,8 @@ import androidx.recyclerview.widget.RecyclerView
 
 private const val DEBUG = false
 
+private const val LOG_TAG = "StickyHeader"
+
 open class StickyHeader @JvmOverloads constructor(
  context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
 ) : FrameLayout(context, attrs, defStyleAttr) {
@@ -42,6 +44,12 @@ open class StickyHeader @JvmOverloads constructor(
  header: View,
  y: Float
  ) {
+ if (DEBUG) {
+ Log.d(
+ LOG_TAG,
+ "onShowHeader(y:${y},header:${header},this.header:${this.header})"
+ )
+ }
  if (this.header == header) {
  this.header?.y = y
  return
@@ -63,9 +71,6 @@ open class StickyHeader @JvmOverloads constructor(
  */
 private class StickyHeaderDecoration(private val onShowHeader: (View, Float) -> Unit) :
  RecyclerView.ItemDecoration() {
- companion object {
- private const val LOG_TAG = "ExpandStickyHeaderD"
- }
 
 
  private var headerGroup = -1
@@ -88,7 +93,7 @@ private class StickyHeaderDecoration(private val onShowHeader: (View, Float) ->
 
  override fun onChanged() {
  super.onChanged()
- header = null
+// header = null
  }
  }
 

gradle/wrapper/gradle-wrapper.properties

@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.5-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.0.2-bin.zip