RecycleView属于android基础组件，比较常用，下面总结下其使用的基础流程及常见问题解决办法（常见问题会定期更新）
基础使用
- 首先在xml里引入RecycleView
<?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="match_parent"tools:context=".RecycleTestActivity"><SeekBarandroid:id="@+id/sk"app:layout_constraintTop_toTopOf="parent"android:layout_width="match_parent"android:padding="20dp"android:layout_height="wrap_content"/><androidx.recyclerview.widget.RecyclerViewandroid:id="@+id/recyclerView"android:layout_marginTop="50dp"android:layout_width="match_parent"android:layout_height="match_parent"android:scrollbars="vertical"app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"/>
</androidx.constraintlayout.widget.ConstraintLayout>
- 编写adapter，分以下几步
1.创建自定义adapter类,创建内部类MyViewHolder,并实现RecycleView的ViewHolder,参数传递view
class MyAdapter(val data:List<Int>) {class MyHolder(view:View):ViewHolder(view){}
}
- 创建item layout，里面根据需要创建对应的布局，这里假如里面仅有一个progressbar,注意根布局高度改为wrap content，否则的话实际效果每个item占用了一屏
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="match_parent"android:layout_height="wrap_content"xmlns:app="http://schemas.android.com/apk/res-auto"><ProgressBarandroid:id="@+id/progress"android:layout_width="wrap_content"android:layout_height="wrap_content"style="@style/Widget.AppCompat.ProgressBar.Horizontal"app:layout_constraintLeft_toLeftOf="parent"app:layout_constraintTop_toTopOf="parent"/>
</androidx.constraintlayout.widget.ConstraintLayout>
3.在MyHolder里获取到progressBar
class MyAdapter(val data:List<Int>) {class MyHolder(view:View):ViewHolder(view){val progressBar:ProgressBar = view.findViewById(R.id.progress)}
}
4.MyAdapter继承Recycleview.Adapter,并实现对应的三个方法
class MyAdapter(val data:List<Int>):Adapter<MyAdapter.MyHolder>() {class MyHolder(view:View):ViewHolder(view){val progressBar:ProgressBar = view.findViewById(R.id.progress)}override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyHolder {TODO("Not yet implemented")}override fun getItemCount(): Int {TODO("Not yet implemented")}override fun onBindViewHolder(holder: MyHolder, position: Int) {TODO("Not yet implemented")}
}
- 在onCreateViewHolder里创建MyHolder并返回，在getItemCount里返回 data.size,在onBindViewHolder里绑定组件
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyHolder {val view = LayoutInflater.from(parent.context).inflate(R.layout.my_item, parent, false)return MyHolder(view)}override fun getItemCount(): Int {return data.size}override fun onBindViewHolder(holder: MyHolder, position: Int) {holder.progressBar.progress = data[position]}
- 在activity里获取recycleView，设置adapter 设置manager，adapter创建时把数据传入
recyclerView = findViewById(R.id.recyclerView)myAdapter = MyAdapter(list)recyclerView.adapter = myAdapterrecyclerView.layoutManager = LinearLayoutManager(this)
遇到的问题
1.当item里有progress bar时，数据变化让progress bar进度条变化，此时没什么问题，但如果progress bar设置了自定义的progressDrawable，那么其中一个item的进度条变化就会导致别的item显示的progress进度出现异常
android:progressDrawable="@drawable/progress_bg"
progress_bg文件内容
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android"><!--背景色--><item android:id="@+id/background"><shape><corners android:radius="100px" /><solid android:color="@color/progress_track" /></shape></item><!--进度条色--><item android:id="@+id/progress"><clip android:clipOrientation="horizontal"><shape><corners android:radius="100px" /><solid android:color="@color/progress_indicator" /></shape></clip></item>
</layer-list>
解决办法：
在onBindViewHolder时调用 holder.ProgressBar.progressDrawable.mutate()
override fun onBindViewHolder(holder: MyViewHolder, position: Int) {holder.ProgressBar.progressDrawable.mutate()
)
