列表局部刷新：
01.notifyDataSetChanged() 刷新全部可见的item
02.notifyItemChanged(int position) 更新列表position位置上的数据可以调用
03.notifyItemInserted(int position) 列表position位置添加一条数据时可以调用，伴有动画效果
04.notifyItemRemoved(int position) 列表position位置移除一条数据时调用，伴有动画效果
05.notifyItemMoved(int fromPosition, int toPosition) 列表fromPosition位置的数据移到toPosition位置时调用，伴有动画效果
06.notifyItemRangeChanged(int positionStart, int itemCount) 列表从positionStart位置到itemCount数量的列表项进行数据刷新
07.notifyItemRangeInserted(int positionStart, int itemCount) 列表从positionStart位置到itemCount数量的列表项批量添加数据时调用，伴有动画效果
08.notifyItemRangeRemoved(int positionStart, int itemCount) 列表从positionStart位置到itemCount数量的列表项批量删除数据时调用，伴有动画效果
一、payload、notifyItemChanged()实现局部刷新：
1.在适配器中定义onBindViewHolder(holder: ViewHolder, position: Int, payloads: MutableList)方法：
class NewsAdapter : ListAdapter<Data, NewsAdapter.ViewHolder>(Diff()) {
//构建ListView的数据比较结果
class Diff : DiffUtil.ItemCallback<Data>() {
override fun areItemsTheSame(oldItem: Data, newItem: Data): Boolean {
return oldItem.hashId == newItem.hashId
}
override fun areContentsTheSame(oldItem: Data, newItem: Data): Boolean {
return oldItem.content == newItem.content
}
}
inner class ViewHolder(view: View) : RecyclerView.ViewHolder(view) {
val tvContent: TextView = view.findViewById(R.id.tvContent)
var tvPlay: TextView = view.findViewById(R.id.tvPlay)
var tvPlay1: TextView = view.findViewById(R.id.tvPlay1)
var tvPlay2: TextView = view.findViewById(R.id.tvPlay2)
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
val view = LayoutInflater.from(parent.context).inflate(R.layout.layout_joke_list_item, parent, false)
return ViewHolder(view)
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
holder.tvContent.text = getItem(position).content
holder.tvPlay.text = "播放"
holder.tvPlay1.text = "播放"
holder.tvPlay2.text = "播放"
}
//局部刷新Item
override fun onBindViewHolder(holder: ViewHolder, position: Int, payloads: MutableList<Any>) {
if(payloads.isEmpty()) {
onBindViewHolder(holder, position)
} else {
for (i in 0 until payloads.size) {
when(payloads[i].toString()) {
"aaa" -> {
holder.tvContent.text = "000"
}
"bbb" -> {
holder.tvPlay.text = "222"
}
}
}
}
}
}
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2.使用notifyItemChanged()进行局部刷新：
class MainActivity : AppCompatActivity() {
private lateinit var recycler: RecyclerView
private lateinit var mAdapter: NewsAdapter
val data = listOf(
Data("123", "123", 1, "123"),
Data("456", "456", 1, "456"),
Data("789", "789", 1, "789")
)
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
recycler = findViewById(R.id.recycler)
mAdapter = NewsAdapter()
val layoutManager = LinearLayoutManager(this)
recycler.layoutManager = layoutManager
recycler.adapter = mAdapter
mAdapter.submitList(data)
//点击局部刷新
findViewById<Button>(R.id.btn).setOnClickListener {
mAdapter.notifyItemChanged(2, "aaa")
mAdapter.notifyItemChanged(0, "aaa")
mAdapter.notifyItemChanged(1, "aaa")
mAdapter.notifyItemChanged(2, "bbb")
mAdapter.notifyItemChanged(0, "bbb")
mAdapter.notifyItemChanged(1, "bbb")
}
}
}
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3.MainActivity布局文件：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity">
<Button
android:id="@+id/btn"
android:text="局部刷新"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recycler"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</LinearLayout>
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4.列表Item布局文件：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<androidx.cardview.widget.CardView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:background="@android:color/white">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="8dp">
<TextView
android:id="@+id/tvContent"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textColor="@android:color/black"
android:textStyle="bold" />
<TextView
android:id="@+id/tvPlay"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="end"
android:text="哈哈" />
<TextView
android:id="@+id/tvPlay1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="end"
android:text="哈哈" />
<TextView
android:id="@+id/tvPlay2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="end"
android:text="哈哈" />
</LinearLayout>
</androidx.cardview.widget.CardView>
</RelativeLayout>
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