《进阶之光》笔记(1)——RecyclerView

最新推荐文章于 2025-12-15 14:43:46 发布

转载最新推荐文章于 2025-12-15 14:43:46 发布 · 125 阅读

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原文链接：https://my.oschina.net/u/3620480/blog/1510768

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#移动开发 #java

本文深入探讨了Android5.0中RecyclerView的使用方法及优势，包括其在替代ListView和GridView方面的表现，如何通过Gradle配置，布局设置，以及自定义分割线和点击事件等高级功能。

主类

package com.zjw.chapter1androidnewcharacteristics;

import android.content.DialogInterface;
import android.graphics.Color;
import android.os.Bundle;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.view.View;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.List;

import butterknife.BindView;
import butterknife.ButterKnife;

//1.1 p1 Android 5.0 新特性
/*
Android 5.0 Lollipop 棒棒糖 API 21
 */

//1.1.2 p3 替换ListView和GridView的RecyclerView
/*
RecyclerView
优点：高度解耦，灵活，效率更高
缺点：分割线需要自定义，列表点击事件要自己实现、
 */
/*
RecyclerView使用：
1.配置Gradle
compile 'com.android.support:recyclerview-v7:25.3.1'
2.布局
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <android.support.v7.widget.RecyclerView
        android:id="@+id/rv"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:divider="#FFB900"
        android:dividerHeight="1dp"
        />
</LinearLayout>
3.找控件设置布局管理器、动画、设配器
其中LinearLayoutManager默认是垂直，
可用linearLayoutManager.setOrientation(LinearLayoutManager.HORIZONTAL)设为水平
4.设置分割线
addItemDecoration()来添加分割线，我们要继承RecyclerView.ItemDecoration来自定义分割线
setColorFilter()第二个参数：PorterDuff.Mode枚举值：
    1.PorterDuff.Mode.CLEAR
    所绘制不会提交到画布上。
    2.PorterDuff.Mode.SRC
    显示上层绘制图片
    3.PorterDuff.Mode.DST
    显示下层绘制图片
    4.PorterDuff.Mode.SRC_OVER
    正常绘制显示，上下层绘制叠盖。
    5.PorterDuff.Mode.DST_OVER
    上下层都显示。下层居上显示。
    6.PorterDuff.Mode.SRC_IN
    取两层绘制交集。显示上层。
    7.PorterDuff.Mode.DST_IN
     取两层绘制交集。显示下层。
    8.PorterDuff.Mode.SRC_OUT
     取上层绘制非交集部分。
    9.PorterDuff.Mode.DST_OUT
    取下层绘制非交集部分。
    10.PorterDuff.Mode.SRC_ATOP
    取下层非交集部分与上层交集部分
    11.PorterDuff.Mode.DST_ATOP
5.自定义点击事件
在adapter中设置接口回调,主类中进行监听
6.实现GridView

 */

public class MainActivity extends AppCompatActivity {

    @BindView(R.id.rv)
    RecyclerView mRv;

    List<String> mDataList = new ArrayList<>();
    private RvAdapter mRvAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.bind(this);//绑定黄油刀

        initData();//recyclerView数据

        initView();//设置recyclerView的布局管理器、动画、分割线、设配器

        initEvent();//设置recyclerView的点击监听
    }

    //recyclerView数据
    private void initData() {
        for (int i = 0; i < 500; i++) {
            mDataList.add("" + i);
        }
    }

    //设置布局管理器、动画、分割线、设配器
    private void initView() {
//        //线性布局
//        mRv.setLayoutManager(new LinearLayoutManager(this));//设置布局管理器
//        mRv.setItemAnimator(new DefaultItemAnimator());//设置item增加和删除时的动画
//        mRv.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL_LIST, Color.BLUE));//设置分割线

//        //表格布局也可以用瀑布流管理器
//        mRv.setLayoutManager(new StaggeredGridLayoutManager(4,StaggeredGridLayoutManager.VERTICAL));
//        mRv.addItemDecoration(new DividerGridItemDecoration(this, Color.YELLOW));

        //瀑布流，在adapter里写一个随机高度来控制每个item的高度
        mRv.setLayoutManager(new StaggeredGridLayoutManager(4, StaggeredGridLayoutManager.VERTICAL));
        mRv.addItemDecoration(new DividerGridItemDecoration(this, Color.YELLOW));


        //设配器
        mRvAdapter = new RvAdapter(this, mDataList);
        mRv.setAdapter(mRvAdapter);//设置设配器
    }

    private void initEvent() {
        mRvAdapter.setOnItemClickListener(new RvAdapter.onItemClickListener() {
            @Override
            public void onItemClick(View view, int position) {
                showToast("点击第" + position + "条");
            }

            @Override
            public void onItemLongClick(View view, final int position) {
                new AlertDialog.Builder(MainActivity.this)
                        .setTitle("确认删除吗？")
                        .setNegativeButton("取消", null)
                        .setPositiveButton("确定", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                mRvAdapter.removeData(position);
                            }
                        }).show();
            }
        });
    }

    //用来弹吐司
    private static Toast mToast;

    public void showToast(String msg) {
        if (mToast == null) {
            mToast = Toast.makeText(this, "", Toast.LENGTH_SHORT);
        }
        mToast.setText(msg);
        mToast.show();
    }
}

适配器

package com.zjw.chapter1androidnewcharacteristics;

import android.content.Context;
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.ArrayList;
import java.util.List;

/**
 * Created by hp on 2017/8/13.
 */

public class RvAdapter extends RecyclerView.Adapter<RvAdapter.RvViewHolder> {
    Context mContext;
    List<String> mDataList;
    public onItemClickListener mOnItemClickListener;
    List<Integer> mHeights;

    public RvAdapter(Context context, List<String> dataList) {
        mContext = context;
        mDataList = dataList;
    }

    public void removeData(int position) {
        mDataList.remove(position);
        notifyDataSetChanged();
    }

    //加载布局条目
    @Override
    public RvViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        RvViewHolder holder = new RvViewHolder(LayoutInflater.from(mContext).inflate(R.layout.rv_item, parent, false));
        return holder;
    }

    //将视图与数据进行绑定
    @Override
    public void onBindViewHolder(final RvViewHolder holder, int position) {
        holder.mTvRvItem.setText(mDataList.get(position));
        if (mOnItemClickListener != null) {
            holder.mTvRvItem.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    int pos = holder.getLayoutPosition();
                    mOnItemClickListener.onItemClick(holder.mTvRvItem, pos);
                }
            });
            holder.mTvRvItem.setOnLongClickListener(new View.OnLongClickListener() {
                @Override
                public boolean onLongClick(View v) {
                    int pos = holder.getLayoutPosition();
                    mOnItemClickListener.onItemLongClick(holder.mTvRvItem, pos);
                    return false;
                }
            });
        }
        //设置高度
        setHeight();
        ViewGroup.LayoutParams layoutParams = holder.mTvRvItem.getLayoutParams();
        layoutParams.height = mHeights.get(position);
        holder.mTvRvItem.setLayoutParams(layoutParams);
    }

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

    public class RvViewHolder extends RecyclerView.ViewHolder {
        TextView mTvRvItem;

        public RvViewHolder(View itemView) {
            super(itemView);
            mTvRvItem = (TextView) itemView.findViewById(R.id.tv_rv_item);
        }
    }

    //点击事件接口回调
    public interface onItemClickListener {
        void onItemClick(View view, int position);

        void onItemLongClick(View view, int position);
    }

    public void setOnItemClickListener(onItemClickListener onItemClickListener) {
        mOnItemClickListener = onItemClickListener;
    }

    public void setHeight() {
        mHeights = new ArrayList<>();
        for (int i = 0; i < mDataList.size(); i++) {
            mHeights.add((int) (100 + Math.random() * 300));
        }
    }
}

分割线1

package com.zjw.chapter1androidnewcharacteristics;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.PorterDuff;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;

/**
 * Created by hp on 2017/8/13.
 */

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 mDrawable;
    private int mOrientation;
    private int mColor = -1;

    public DividerItemDecoration(Context context, int orientation) {
        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDrawable = a.getDrawable(0);
        a.recycle();
        setOrientation(orientation);
    }

    public DividerItemDecoration(Context context, int orientation, int color) {
        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDrawable = a.getDrawable(0);
        a.recycle();
        setOrientation(orientation);
        setColor(color);
    }

    //设置分割线方向
    public void setOrientation(int orientation) {
        if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST) {
            throw new IllegalArgumentException("invalid orientation");
        }
        mOrientation = orientation;
    }

    //设置分割线颜色
    public void setColor(int color) {
        mColor = color;
    }

    @Override
    public void onDraw(Canvas c, RecyclerView parent) {
        if (mOrientation == VERTICAL_LIST) {//画垂直方向上的分割线(横的)
            drawVertical(c, parent);
        } else {
            drawHorizontal(c, parent);//画水平方向上的分割线(竖的)
        }
    }

    //画垂直方向上的分割线(横的)
    private 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.LayoutParams layoutParams = (RecyclerView.LayoutParams) child.getLayoutParams();
            int top = child.getBottom() + layoutParams.bottomMargin;
            int bottom = top + mDrawable.getIntrinsicHeight();
            mDrawable.setBounds(left, top, right, bottom);
            if (mColor != -1) {
                mDrawable.setColorFilter(mColor, PorterDuff.Mode.DST_OVER);
            }
            mDrawable.draw(c);
        }
    }

    //画水平方向上的分割线(竖的)
    private void drawHorizontal(Canvas c, RecyclerView parent) {
        int top = parent.getPaddingTop();
        int bottom = parent.getHeight() - parent.getPaddingBottom();
        final int childCount = parent.getChildCount();
        for (int i = 0; i < childCount; i++) {
            final View child = parent.getChildAt(i);
            RecyclerView.LayoutParams layoutParams = (RecyclerView.LayoutParams) child.getLayoutParams();
            int left = child.getRight() + layoutParams.rightMargin;
            int right = left + mDrawable.getIntrinsicWidth();
            mDrawable.setBounds(left, top, right, bottom);
            if (mColor != -1) {
                mDrawable.setColorFilter(mColor, PorterDuff.Mode.DST_OVER);
            }
            mDrawable.draw(c);
        }
    }

    //设置item分割线的size
    @Override
    public void getItemOffsets(Rect outRect, int itemPosition, RecyclerView parent) {
        if (mOrientation == VERTICAL_LIST) {
            outRect.set(0, 0, 0, mDrawable.getIntrinsicHeight());
        } else {
            outRect.set(0, 0, mDrawable.getIntrinsicWidth(), 0);
        }
    }
}

分割线2

package com.zjw.chapter1androidnewcharacteristics;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.PorterDuff;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v7.widget.RecyclerView;
import android.view.View;

/**
 * Created by hp on 2017/8/13.
 */

public class DividerGridItemDecoration extends RecyclerView.ItemDecoration {
    private static final int[] ATTRS = new int[]{
            android.R.attr.listDivider
    };

    private Drawable mDrawable;
    private int mColor = -1;

    public DividerGridItemDecoration(Context context) {
        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDrawable = a.getDrawable(0);
        a.recycle();
    }

    public DividerGridItemDecoration(Context context,int color) {
        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDrawable = a.getDrawable(0);
        a.recycle();
        setColor(color);
    }

    //设置分割线颜色
    public void setColor(int color) {
        mColor = color;
    }

    @Override
    public void onDraw(Canvas c, RecyclerView parent) {
            drawVertical(c, parent);
            drawHorizontal(c, parent);//画水平方向上的分割线(竖的)
    }

    //画垂直方向上的分割线(横的)
    private 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.LayoutParams layoutParams = (RecyclerView.LayoutParams) child.getLayoutParams();
            int top = child.getBottom() + layoutParams.bottomMargin;
            int bottom = top + mDrawable.getIntrinsicHeight();
            mDrawable.setBounds(left, top, right, bottom);
            if (mColor != -1) {
                mDrawable.setColorFilter(mColor, PorterDuff.Mode.DST_OVER);
            }
            mDrawable.draw(c);
        }
    }

    //画水平方向上的分割线(竖的)
    private void drawHorizontal(Canvas c, RecyclerView parent) {
        int top = parent.getPaddingTop();
        int bottom = parent.getHeight() - parent.getPaddingBottom();
        final int childCount = parent.getChildCount();
        for (int i = 0; i < childCount; i++) {
            final View child = parent.getChildAt(i);
            RecyclerView.LayoutParams layoutParams = (RecyclerView.LayoutParams) child.getLayoutParams();
            int left = child.getRight() + layoutParams.rightMargin;
            int right = left + mDrawable.getIntrinsicWidth();
            mDrawable.setBounds(left, top, right, bottom);
            if (mColor != -1) {
                mDrawable.setColorFilter(mColor, PorterDuff.Mode.DST_OVER);
            }
            mDrawable.draw(c);
        }
    }

    //设置item分割线的size
    @Override
    public void getItemOffsets(Rect outRect, int itemPosition, RecyclerView parent) {
            outRect.set(0, 0,mDrawable.getIntrinsicWidth(), mDrawable.getIntrinsicHeight());
    }
}

主布局一个recyclerView,item布局一个TextView

转载于:https://my.oschina.net/u/3620480/blog/1510768