Android开发----RecyclerView视图的学习

RecyclerView

RecyclerView是什么？

RecyclerView是如今Android开发中最常用的控件，其相较于ListView和GridView的功能更为强大，优化了两者的各种不足，同时可以开发出各种View。

要使用RecyclerView，首先要在build.gradle中添加依赖

implementation 'com.android.support:recyclerview-v7:27.1.1'

RecyclerView实现ListView

新建一个Empty Activity名为LinearRecyclerView

先做好前提准备，定义布局文件activity_linear_recycler_view.xml

<?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="match_parent"
    >

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/rv_main"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#ffffff"/>

</RelativeLayout>

新建一个LinearAdapt.java

public class LinearAdapter extends RecyclerView.Adapter<LinearAdapter.LinearViewHolder> {

    private Context context;
    private OnItemClickListener listener;

    public LinearAdapter(Context context, OnItemClickListener listener) {
        this.context = context;
        this.listener = listener;
    }

    @NonNull
    @Override
    public LinearAdapter.LinearViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        return new LinearViewHolder(LayoutInflater.from(context).inflate(R.layout.activity_linear_recycler,parent,false));
    }

    @Override
    public void onBindViewHolder(@NonNull LinearAdapter.LinearViewHolder holder, final int position) {
        holder.textView.setText("Hello World");
        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
//                Toast.makeText(context,"click...."+position,Toast.LENGTH_SHORT).show();
                listener.onClick(position);
            }
        });
    }

    @Override
    public int getItemCount() {
        return 30;
    }

    class LinearViewHolder extends RecyclerView.ViewHolder{

        private TextView textView;

        public LinearViewHolder(@NonNull View itemView) {
            super(itemView);
            textView = itemView.findViewById(R.id.tvv_1);
        }
    }

    public interface OnItemClickListener{
        void onClick(int pos);
    }

}

再创建一个新的布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <TextView
        android:id="@+id/tvv_1"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:gravity="center"
        android:textColor="#000"
        android:text="asdasda"/>

</LinearLayout>

准备工作做好之后，我们就可以开始为控件写活动了

public class LinearRecyclerViewActivity extends AppCompatActivity {

    private RecyclerView mrvmain;

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

        mrvmain = findViewById(R.id.rv_main);
        mrvmain.setLayoutManager(new LinearLayoutManager(LinearRecyclerViewActivity.this));
        mrvmain.addItemDecoration(new MyDecoration());
        mrvmain.setAdapter(new LinearAdapter(LinearRecyclerViewActivity.this, new LinearAdapter.OnItemClickListener() {
            @Override
            public void onClick(int pos) {
                Toast.makeText(LinearRecyclerViewActivity.this,"click...."+pos,Toast.LENGTH_SHORT).show();
            }
        }));
    }

    class MyDecoration extends RecyclerView.ItemDecoration{
        @Override
        public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
            super.getItemOffsets(outRect, view, parent, state);
            outRect.set(0,0,0,getResources().getDimensionPixelOffset(R.dimen.dividerHight));
        }
    }
}

效果展示如图：