2020-08-21

android之recyclerview(一)

RecyclerView是谷歌推出的代替ListView的列表控件。
1.导入依赖,在build.gradle下添加recyclerview的依赖

implementation 'com.android.support:recyclerview-v7:27.0.0'

2.进行使用

效果图: 1.png

package com.example.lineralayout.recyclerview;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

import com.example.lineralayout.R;

public class RecyclerviewActivity extends AppCompatActivity {
    private Button mBtnLinear;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_recyclerview);
        mBtnLinear = findViewById(R.id.btn_linear);
        mBtnLinear.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(RecyclerviewActivity.this,LinearRecyclerViewActivity.class);
                startActivity(intent);
            }
        });
    }
}

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:orientation="vertical"
    android:layout_height="match_parent"
    tools:context=".recyclerview.RecyclerviewActivity">
    <Button
        android:id="@+id/btn_linear"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="列表视图"/>

</LinearLayout>

Linear类

package com.example.lineralayout.recyclerview;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.graphics.Rect;
import android.os.Bundle;
import android.view.View;

import com.example.lineralayout.R;

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));
    }
    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.dividerHeight));
        }
    }
}

对应xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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=".recyclerview.LinearRecyclerViewActivity">
<androidx.recyclerview.widget.RecyclerView
    android:id="@+id/rv_main"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@color/colorGrayDark"/>
</RelativeLayout>

recyclerview分割线的方法,

.addItemDeciration 

RecyclerView.Adapter适配器

RecyclerView.Adapter，一个抽象类，并支持泛型

public static abstract class Adapter<VH extends ViewHolder> {
   ...
}

重写的三个方法:

1：public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType)

2：public void onBindViewHolder(RecyclerView.ViewHolder holder, int position)

3：public int getItemCount()

点击事件(注:也可以自定义一个接口来实现)

  holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Toast.makeText(mContext,"click..."+position,Toast.LENGTH_SHORT).show();
            }
        });