Recyclerview

Recyclerview

可以替换ListView

导入依赖：

implementation ‘com.android.support:recyclerview-v7:28.0.0’

xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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=".MainActivity">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recycler"
        android:layout_width="match_parent"
        android:layout_height="match_parent"></androidx.recyclerview.widget.RecyclerView>
</LinearLayout>

Activity

public class MainActivity extends AppCompatActivity {

    RecyclerView recyclerView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        recyclerView = findViewById(R.id.recycler);

//        LinearLayoutManager manager = new LinearLayoutManager(this);
//        manager.setOrientation(LinearLayoutManager.VERTICAL); //列表

//        GridLayoutManager gridLayoutManager = new GridLayoutManager(this,3); //网格


        StaggeredGridLayoutManager manager = new StaggeredGridLayoutManager(2,StaggeredGridLayoutManager.VERTICAL);
        recyclerView.setLayoutManager(manager);

        ArrayList<Integer> strings = new ArrayList<>();
        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
        String currentData = dateFormat.format(new Date());
        strings.add(R.mipmap.t1);
        strings.add(R.mipmap.t2);
        strings.add(R.mipmap.t3);
        strings.add(R.mipmap.t4);
        strings.add(R.mipmap.t5);
        strings.add(R.mipmap.t6);
        strings.add(R.mipmap.t1);
        strings.add(R.mipmap.t2);
        strings.add(R.mipmap.t3);
        strings.add(R.mipmap.t4);
        strings.add(R.mipmap.t5);
        strings.add(R.mipmap.t6);


        MyAdapter myAdapter = new MyAdapter(strings,this);
        recyclerView.setAdapter(myAdapter);


        DefaultItemAnimator defaultItemAnimator  = new DefaultItemAnimator();
//        defaultItemAnimator.setAddDuration(2000);
//        defaultItemAnimator.setRemoveDuration(2000);
        recyclerView.setItemAnimator(defaultItemAnimator);  //设置删除和添加的动画

        DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(this,DividerItemDecoration.VERTICAL);
//        dividerItemDecoration.setDrawable(new ColorDrawable(234234));
        recyclerView.addItemDecoration(dividerItemDecoration);  //分割线

    }
}

适配器

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHoder> {


    ArrayList<Integer> strings;
    Context context;

    public MyAdapter(ArrayList<Integer> strings,Context context)
    {
        this.strings = strings;
        this.context = context;
    }

    @NonNull
    @Override
    public MyViewHoder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
        View itemView = LayoutInflater.from(context).inflate(R.layout.item_layout,null);
        MyViewHoder viewHoder = new MyViewHoder(itemView);
        return viewHoder;
    }

    @Override
    public void onBindViewHolder(@NonNull MyViewHoder myViewHoder, final int i) {

        int hightValue =(int)(Math.random()*801+100);
       ViewGroup.LayoutParams layoutParams = (ViewGroup.LayoutParams) myViewHoder.imageView.getLayoutParams();
        layoutParams.height = hightValue;
        myViewHoder.imageView.setLayoutParams(layoutParams);

        myViewHoder.imageView.setImageResource(strings.get(i));

        myViewHoder.imageView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                strings.remove(i);
                notifyItemRemoved(i);
                notifyItemRangeChanged(i,strings.size());
            }
        });

        myViewHoder.imageView.setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View v) {
                strings.add(R.mipmap.t4);
                notifyItemInserted(i);
                return true;
            }
        });
    }

    @Override
    public int getItemCount() {
        return strings.size();
    }


    class MyViewHoder extends RecyclerView.ViewHolder
    {
        ImageView imageView;
        public MyViewHoder(@NonNull View itemView) {
            super(itemView);
            imageView = itemView.findViewById(R.id.image);
        }
    }

}