Android 控件 RecyclerView 的使用

痛定思痛。 2024-04-17 05:39 90阅读 0赞

### 一、RecyclerView是什么 ###

从Android 5.0开始，谷歌公司推出了一个用于大量数据展示的新控件RecylerView，可以用来代替传统的ListView，更加强大和灵活。RecyclerView是**support-v7包**中的**新组件**，是一个强大的滑动组件，与经典的ListView相比，同样拥有item回收复用的功能，这一点从它的名字Recyclerview即回收view也可以看出。

### 二、基本使用 ###

1.引入依赖

implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.android.support:recyclerview-v7:28.0.0'
    implementation 'jp.wasabeef:recyclerview-animators:2.2.7'

2.主布局（activity\_main.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"
        android:orientation="vertical"
        tools:context=".MainActivity">
    
        <Button
            android:id="@+id/id_add"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="增加" />
    
        <Button
            android:id="@+id/id_del"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="删除" />
    
        <android.support.v7.widget.RecyclerView
            android:id="@+id/id_recyclerView"
            android:layout_width="match_parent"
            android:layout_height="match_parent"/>
    </LinearLayout>

3.item布局（activity\_itemview.xml）

<?xml version="1.0" encoding="utf-8"?>
    <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:background="@color/colorAccent"
        android:layout_height="72dp">
    
        <TextView
            android:id="@+id/id_tv"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:gravity="center" />
    
    </FrameLayout>

4.自定义分割线，在res/drawable下新建divider.xml

<?xml version="1.0" encoding="utf-8"?>
    <shape xmlns:android="http://schemas.android.com/apk/res/android"
        android:shape="rectangle">
    
        <size android:height="2dp" />
    
        <gradient
            android:centerColor="@color/colorCenter"
            android:endColor="@color/colorEnd"
            android:startColor="@color/colorStart"
            android:type="linear"></gradient>
    
    </shape>

5.将自定义的分割线在style.xml里进行应用

<resources>
    
        
        <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
            
            <item name="colorPrimary">@color/colorPrimary</item>
            <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
            <item name="colorAccent">@color/colorAccent</item>
            <item name="android:listDivider">@drawable/divider</item>
        </style>
    
    </resources>

6.自定义分割线的工具类

package com.chen.recyclerviewtest;
    
    import android.content.Context;
    import android.content.res.TypedArray;
    import android.graphics.Canvas;
    import android.graphics.Rect;
    import android.graphics.drawable.Drawable;
    import android.support.v7.widget.LinearLayoutManager;
    import android.support.v7.widget.RecyclerView;
    import android.util.Log;
    import android.view.View;
    
    public class DividerItemDecoration extends RecyclerView.ItemDecoration
    {
    
    	private static final int[] ATTRS = new int[] { android.R.attr.listDivider };
    
    	public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;
    
    	public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;
    	
    	
    
    	private Drawable mDivider;
    
    	private int mOrientation;
    
    	public DividerItemDecoration(Context context, int orientation)
    	{
    		final TypedArray a = context.obtainStyledAttributes(ATTRS);
    		mDivider = a.getDrawable(0);
    		a.recycle();
    		setOrientation(orientation);
    	}
    
    	public void setOrientation(int orientation)
    	{
    		if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST)
    		{
    			throw new IllegalArgumentException("invalid orientation");
    		}
    		mOrientation = orientation;
    	}
    
    	@Override
    	public void onDraw(Canvas c, RecyclerView parent)
    	{
    		 if (mOrientation == VERTICAL_LIST) {
    	            drawVertical(c, parent);
    	        } else {
    	            drawHorizontal(c, parent);
    	        }
    	}
    
    	public void drawVertical(Canvas c, RecyclerView parent)
    	{
    		final int left = parent.getPaddingLeft();
    		final int right = parent.getWidth() - parent.getPaddingRight();
    
    		final int childCount = parent.getChildCount();
    
    		for (int i = 0; i < childCount; i++)
    		{
    			final View child = parent.getChildAt(i);
    			RecyclerView v = new RecyclerView(
    					parent.getContext());
    			final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
    					.getLayoutParams();
    			final int top = child.getBottom() + params.bottomMargin;
    			final int bottom = top + mDivider.getIntrinsicHeight();
    			mDivider.setBounds(left, top, right, bottom);
    			mDivider.draw(c);
    		}
    	}
    
    	public void drawHorizontal(Canvas c, RecyclerView parent)
    	{
    		final int top = parent.getPaddingTop();
    		final int bottom = parent.getHeight() - parent.getPaddingBottom();
    
    		final int childCount = parent.getChildCount();
    		for (int i = 0; i < childCount; i++)
    		{
    			final View child = parent.getChildAt(i);
    			final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
    					.getLayoutParams();
    			final int left = child.getRight() + params.rightMargin;
    			final int right = left + mDivider.getIntrinsicHeight();
    			mDivider.setBounds(left, top, right, bottom);
    			mDivider.draw(c);
    		}
    	}
    
    	@Override
    	public void getItemOffsets(Rect outRect, int itemPosition,
    			RecyclerView parent)
    	{
    		if (mOrientation == VERTICAL_LIST)
    		{
    			outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
    		} else
    		{
    			outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
    		}
    	}
    }

7.MainActivity主界面

package com.chen.recyclerviewtest;
    
    import android.support.v4.widget.SwipeRefreshLayout;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.support.v7.widget.DefaultItemAnimator;
    import android.support.v7.widget.GridLayoutManager;
    import android.support.v7.widget.LinearLayoutManager;
    import android.support.v7.widget.RecyclerView;
    import android.view.View;
    import android.widget.Button;
    import android.widget.Toast;
    
    import java.util.ArrayList;
    import java.util.List;
    
    
    public class MainActivity extends AppCompatActivity {
    
        private List<String> mData;
        private RecyclerView recyclerView;
        private SimpleAdapter simpleAdapter;
        private Button btn_add;
        private Button btn_del;
    
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    
            initData();
            initView();
            simpleAdapter=new SimpleAdapter(this,mData);
            recyclerView.setAdapter(simpleAdapter);
    
            //设置RecyclerView布局管理器
            LinearLayoutManager linearLayoutManager=new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false);
            recyclerView.setLayoutManager(linearLayoutManager);
            //recyclerView.setLayoutManager(new GridLayoutManager(this,2));
            //设置分分割线
            recyclerView.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL_LIST));
            //设置动画效果
            recyclerView.setItemAnimator(new DefaultItemAnimator());
    
            btn_add.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    simpleAdapter.addData(mData.size());
                }
            });
    
            btn_del.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    simpleAdapter.deleteData(mData.size()-1);
                }
            });
    
            simpleAdapter.setOnItemClickListener(new SimpleAdapter.OnItemClickListener() {
                @Override
                public void onItemClick(View view, int position) {
                    Toast.makeText(MainActivity.this,"点击"+position,Toast.LENGTH_SHORT).show();
                }
    
                @Override
                public void onItemLongClick(View view, int position) {
                    Toast.makeText(MainActivity.this,"长按"+position,Toast.LENGTH_SHORT).show();
                }
            });
        }
    
        private void initView(){
            recyclerView=findViewById(R.id.id_recyclerView);
            btn_add=findViewById(R.id.id_add);
            btn_del=findViewById(R.id.id_del);
        }
    
        private void initData(){
            mData=new ArrayList<String>();
    
            for (int i='A';i<='z';i++){
                mData.add(""+(char)i);
            }
        }
    }

8.设置适配器

package com.chen.recyclerviewtest;
    
    import android.content.Context;
    import android.support.annotation.NonNull;
    import android.support.v7.widget.RecyclerView;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.TextView;
    
    import java.util.List;
    
    public class SimpleAdapter extends RecyclerView.Adapter<MyViewHolder> {
    
        private LayoutInflater mInflater;
        private Context mContext;
        private List<String> mData;
    
        public interface OnItemClickListener{
            void onItemClick(View view,int position);
            void onItemLongClick(View view,int position);
        }
    
        private OnItemClickListener onItemClickListener;
    
        public void setOnItemClickListener(OnItemClickListener listener){
            this.onItemClickListener=listener;
        }
    
        public SimpleAdapter(Context context,List<String> datas) {
            this.mContext=context;
            this.mData=datas;
            mInflater=LayoutInflater.from(context);
        }
    
        @NonNull
        @Override
        public MyViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
    
            View view=mInflater.inflate(R.layout.activity_itemview,viewGroup,false);
            MyViewHolder viewHolder=new MyViewHolder(view);
            return viewHolder;
        }
    
        @Override
        public void onBindViewHolder(@NonNull final MyViewHolder myViewHolder, final int i) {
            myViewHolder.tv.setText(mData.get(i));
    
            if(onItemClickListener!=null){
                myViewHolder.itemView.setOnClickListener(new View.OnClickListener(){
                    public void onClick(View v){
                        onItemClickListener.onItemClick(myViewHolder.itemView,i);
                    }
                });
                myViewHolder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
                    @Override
                    public boolean onLongClick(View v) {
                        onItemClickListener.onItemLongClick(myViewHolder.itemView,i);
                        return false;
                    }
                });
            }
    
        }
    
        @Override
        public int getItemCount() {
            return mData.size();
        }
    
        public void addData(int pos){
            mData.add(pos,"哈哈哈");
            notifyItemInserted(pos);
        }
    
        public void deleteData(int pos){
            mData.remove(pos);
            notifyItemRemoved(pos);
        }
    }
    
    class MyViewHolder extends RecyclerView.ViewHolder {
    
        TextView tv;
        public MyViewHolder(@NonNull View itemView) {
            super(itemView);
            tv=itemView.findViewById(R.id.id_tv);
        }
    }

实现效果：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQyMTA5NzQ2_size_16_color_FFFFFF_t_70][]

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