android 5.0新特性学习--RecyclerView

2022-01-26 22:10:53

在过去很多年，我们的PC或者手机设备都是采用拟物化的设计风格，IOS采用扁平化的特性，android在2014年IO大会上说采用Material Design的设计风格，显示效果不能过于生硬的转换，而是平滑，过度的切换方式，避免线性的动画效果，而是代替以曲线的效果进行展示，并且所有的图标的动画切换都应该无缝化切换。

如果想深入了解材料设计即（material Design）的设计：

可以参看如下网址：http://design.1sters.com，尤其是android 应用的UED设计师们，可以看下：

开发中要在libs文件夹下面中加上android_support_v4.jar包

RecyclerView

java.lang.Object
　　android.view.View
　　　　android.view.ViewGroup
　　　　　　android.support.v7.widget.RecyclerView

官网地址：https://developer.android.com/reference/android/support/v7/widget/RecyclerView.html

RecyclerView 一个特点就是，将 layout 抽象成了一个 LayoutManager，RecylerView 不负责子 View 的布局， 我们可以自定义 LayoutManager 来实现不同的布局效果， 目前只提供了LinearLayoutManager。 LinearLayoutManager 可以指定方向，默认是垂直， 可以指定水平， 这样就轻松实现了水平的 ListView。

除了LinearLayoutManager还有其他两种布局管理器：

GridLayoutManager 网格的item
StaggeredGridLayoutManager 交错的网格item

当然也可以通过集成ResyclerView,layoutManager类来自定义自己的布局管理器。

RecyclerView的使用过程中会使用到一个Adapter:RecyclerView.Adapter，里面屏蔽了以前写BaseAdapter的中好多重读的代码的编写，将加载item布局放在onCreateViewHolder（ViewGroup viewGroup, int i）方法中，在onBindViewHolder(ViewHolder viewHolder, int i)中数据加载到item中。用于优化的viewHolder也是继承自RecyclerView.ViewHolder。

RecyclerView不提供setOnItemClickListener方法，你可以在ViewHolder中添加事件。

RecyclerView之间的分割线：

http://my.oschina.net/xesam/blog/351408

官网地址：https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter.html

关于使用可以参考：

http://www.jcodecraeer.com/a/anzhuokaifa/androidkaifa/2014/0710/1631.html

http://blog.csdn.net/cym492224103/article/details/41719497

编写demo:

android 5.0新特性学习--RecyclerView

布局文件：

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

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:id="@+id/activity_main"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    tools:context="com.example.wangfubin.recyclerview.MainActivity">

    <android.support.v7.widget.RecyclerView

        android:id="@+id/id_recyclerview"

        android:divider="#ffff0000"

        android:dividerHeight="10dp"

        android:layout_width="match_parent"

        android:layout_height="match_parent"/>

</RelativeLayout>
item_gridview.xml:
<?xml version="1.0" encoding="utf-8"?>

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="100dp"

    xmlns:tool="http://schemas.android.com/tools"

    android:background="#44ff0000"

    android:layout_height="100dp">

    <TextView

        android:id="@+id/id_num"

        android:layout_width="match_parent"

        android:layout_height="50dp"

        android:gravity="center"

        tool:text="1" />

</FrameLayout>
item_listview.xml
<?xml version="1.0" encoding="utf-8"?>

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    xmlns:tool="http://schemas.android.com/tools"

    android:background="#44ff0000"

    android:layout_height="wrap_content">

    <TextView

        android:id="@+id/id_num"

        android:layout_width="match_parent"

        android:layout_height="50dp"

        android:gravity="center"

        tool:text="1" />

</FrameLayout>
MainActivity.java
import android.os.Bundle;

import android.support.v7.app.AppCompatActivity;

import android.support.v7.widget.DefaultItemAnimator;

import android.support.v7.widget.RecyclerView;

import android.support.v7.widget.StaggeredGridLayoutManager;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.widget.Toast;

import java.util.ArrayList;

import java.util.List;

public class MainActivity extends AppCompatActivity {

    private RecyclerView mRecyclerView;

    private List<String> mDatas;

    private HomeAdapter mAdapter;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        initData();

        mRecyclerView = (RecyclerView) findViewById(R.id.id_recyclerview);

        //垂直线性RecyclerView

        //mRecyclerView.setLayoutManager(new LinearLayoutManager(this));

        //Grid布局

        //mRecyclerView.setLayoutManager(new GridLayoutManager(this,4));

        //瀑布流

        //垂直方向

        //mRecyclerView.setLayoutManager(new StaggeredGridLayoutManager(4, StaggeredGridLayoutManager.VERTICAL));

        //水平方向

        mRecyclerView.setLayoutManager(new StaggeredGridLayoutManager(4, StaggeredGridLayoutManager.HORIZONTAL));

        mRecyclerView.setAdapter(mAdapter = new HomeAdapter(getApplicationContext(),initData()));

        //垂直线性RecyclerView分割线

        //mRecyclerView.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL_LIST));

        //GridView的分隔线

        mRecyclerView.addItemDecoration(new DividerGridItemDecoration(this));

        //添加默认动画

        mRecyclerView.setItemAnimator(new DefaultItemAnimator());

        mAdapter.setOnItemClickLitener(new HomeAdapter.OnItemClickLitener() {

            @Override

            public void onItemClick(View view, int position) {

                Toast.makeText(getApplicationContext(),"单击事件",Toast.LENGTH_SHORT).show();

            }

            @Override

            public void onItemLongClick(View view, int position) {

                Toast.makeText(getApplicationContext(),"长按事件",Toast.LENGTH_SHORT).show();

            }

        });

    }

    /**

     * 初始化模拟数据

     * @return

     */

    protected List<String> initData() {

        mDatas = new ArrayList<String>();

        for (int i = 'A'; i < 'z'; i++) {

            mDatas.add("" + (char) i);

        }

        return mDatas;

    }

    @Override

    public boolean onCreateOptionsMenu(Menu menu)

    {

        getMenuInflater().inflate(R.menu.main, menu);

        return super.onCreateOptionsMenu(menu);

    }

    @Override

    public boolean onOptionsItemSelected(MenuItem item)

    {

        switch (item.getItemId())

        {

            case R.id.id_action_add:

                //新增数据

                mAdapter.addData(1);

                break;

            case R.id.id_action_delete:

                //删除数据

                mAdapter.removeData(1);

                break;

        }

        return true;

    }

}

HomeAdapter.java

import java.util.List;

import android.content.Context;

import android.support.v7.widget.RecyclerView;

import android.support.v7.widget.RecyclerView.ViewHolder;

import android.view.LayoutInflater;

import android.view.View;

import android.view.View.OnClickListener;

import android.view.View.OnLongClickListener;

import android.view.ViewGroup;

import android.widget.TextView;

/**

 * Created by wangfubin on 2016/11/12.

 */

class HomeAdapter extends RecyclerView.Adapter<HomeAdapter.MyViewHolder>

{

    private List<String> mDatas;

    private LayoutInflater mInflater;

    public interface OnItemClickLitener

    {

        void onItemClick(View view, int position);

        void onItemLongClick(View view , int position);

    }

    private OnItemClickLitener mOnItemClickLitener;

    public void setOnItemClickLitener(OnItemClickLitener mOnItemClickLitener)

    {

        this.mOnItemClickLitener = mOnItemClickLitener;

    }

    public HomeAdapter(Context context, List<String> datas)

    {

        mInflater = LayoutInflater.from(context);

        mDatas = datas;

    }

    @Override

    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType)

    {

        MyViewHolder holder = new MyViewHolder(mInflater.inflate(

                R.layout.item_listview, parent, false));

        return holder;

    }

    @Override

    public void onBindViewHolder(final MyViewHolder holder, final int position)

    {

        holder.tv.setText(mDatas.get(position));

        // 如果设置了回调，则设置点击事件

        if (mOnItemClickLitener != null)

        {

            holder.itemView.setOnClickListener(new OnClickListener()

            {

                @Override

                public void onClick(View v)

                {

                    int pos = holder.getLayoutPosition();

                    mOnItemClickLitener.onItemClick(holder.itemView, pos);

                }

            });

            holder.itemView.setOnLongClickListener(new OnLongClickListener()

            {

                @Override

                public boolean onLongClick(View v)

                {

                    int pos = holder.getLayoutPosition();

                    mOnItemClickLitener.onItemLongClick(holder.itemView, pos);

                    removeData(pos);

                    return false;

                }

            });

        }

    }

    @Override

    public int getItemCount()

    {

        return mDatas.size();

    }

    public void addData(int position)

    {

        mDatas.add(position, "Insert One");

        notifyItemInserted(position);

    }

    public void removeData(int position)

    {

        mDatas.remove(position);

        notifyItemRemoved(position);

    }

    class MyViewHolder extends ViewHolder

    {

        TextView tv;

        public MyViewHolder(View view)

        {

            super(view);

            tv = (TextView) view.findViewById(R.id.id_num);

        }

    }

}
DividerItemDecoration.java
/**

 * 垂直水平分割线

 */

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) {

        Log.v("recyclerview - itemdecoration", "onDraw()");

        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);

            android.support.v7.widget.RecyclerView v = new android.support.v7.widget.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);

        }

    }

}
DividerGridItemDecoration.java
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.GridLayoutManager;

import android.support.v7.widget.RecyclerView;

import android.support.v7.widget.RecyclerView.LayoutManager;

import android.support.v7.widget.RecyclerView.State;

import android.support.v7.widget.StaggeredGridLayoutManager;

import android.view.View;

/**

 *GridView分割线

 * @author zhy

 *

 */

public class DividerGridItemDecoration extends RecyclerView.ItemDecoration

{

    private static final int[] ATTRS = new int[] { android.R.attr.listDivider };

    private Drawable mDivider;

    public DividerGridItemDecoration(Context context)

    {

        final TypedArray a = context.obtainStyledAttributes(ATTRS);

        mDivider = a.getDrawable(0);

        a.recycle();

    }

    @Override

    public void onDraw(Canvas c, RecyclerView parent, State state)

    {

        drawHorizontal(c, parent);

        drawVertical(c, parent);

    }

    private int getSpanCount(RecyclerView parent)

    {

        // 列数

        int spanCount = -1;

        LayoutManager layoutManager = parent.getLayoutManager();

        if (layoutManager instanceof GridLayoutManager)

        {

            spanCount = ((GridLayoutManager) layoutManager).getSpanCount();

        } else if (layoutManager instanceof StaggeredGridLayoutManager)

        {

            spanCount = ((StaggeredGridLayoutManager) layoutManager)

                    .getSpanCount();

        }

        return spanCount;

    }

    public void drawHorizontal(Canvas c, RecyclerView parent)

    {

        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.getLeft() - params.leftMargin;

            final int right = child.getRight() + params.rightMargin

                    + mDivider.getIntrinsicWidth();

            final int top = child.getBottom() + params.bottomMargin;

            final int bottom = top + mDivider.getIntrinsicHeight();

            mDivider.setBounds(left, top, right, bottom);

            mDivider.draw(c);

        }

    }

    public void drawVertical(Canvas c, RecyclerView parent)

    {

        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 top = child.getTop() - params.topMargin;

            final int bottom = child.getBottom() + params.bottomMargin;

            final int left = child.getRight() + params.rightMargin;

            final int right = left + mDivider.getIntrinsicWidth();

            mDivider.setBounds(left, top, right, bottom);

            mDivider.draw(c);

        }

    }

    private boolean isLastColum(RecyclerView parent, int pos, int spanCount,

                                int childCount)

    {

        LayoutManager layoutManager = parent.getLayoutManager();

        if (layoutManager instanceof GridLayoutManager)

        {

            if ((pos + 1) % spanCount == 0)// 如果是最后一列，则不需要绘制右边

            {

                return true;

            }

        } else if (layoutManager instanceof StaggeredGridLayoutManager)

        {

            int orientation = ((StaggeredGridLayoutManager) layoutManager)

                    .getOrientation();

            if (orientation == StaggeredGridLayoutManager.VERTICAL)

            {

                if ((pos + 1) % spanCount == 0)// 如果是最后一列，则不需要绘制右边

                {

                    return true;

                }

            } else

            {

                childCount = childCount - childCount % spanCount;

                if (pos >= childCount)// 如果是最后一列，则不需要绘制右边

                    return true;

            }

        }

        return false;

    }

    private boolean isLastRaw(RecyclerView parent, int pos, int spanCount,

                              int childCount)

    {

        LayoutManager layoutManager = parent.getLayoutManager();

        if (layoutManager instanceof GridLayoutManager)

        {

            childCount = childCount - childCount % spanCount;

            if (pos >= childCount)// 如果是最后一行，则不需要绘制底部

                return true;

        } else if (layoutManager instanceof StaggeredGridLayoutManager)

        {

            int orientation = ((StaggeredGridLayoutManager) layoutManager)

                    .getOrientation();

            // StaggeredGridLayoutManager 且纵向滚动

            if (orientation == StaggeredGridLayoutManager.VERTICAL)

            {

                childCount = childCount - childCount % spanCount;

                // 如果是最后一行，则不需要绘制底部

                if (pos >= childCount)

                    return true;

            } else

            // StaggeredGridLayoutManager 且横向滚动

            {

                // 如果是最后一行，则不需要绘制底部

                if ((pos + 1) % spanCount == 0)

                {

                    return true;

                }

            }

        }

        return false;

    }

    @Override

    public void getItemOffsets(Rect outRect, int itemPosition,

                               RecyclerView parent)

    {

        int spanCount = getSpanCount(parent);

        int childCount = parent.getAdapter().getItemCount();

        if (isLastRaw(parent, itemPosition, spanCount, childCount))// 如果是最后一行，则不需要绘制底部

        {

            outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);

        } else if (isLastColum(parent, itemPosition, spanCount, childCount))// 如果是最后一列，则不需要绘制右边

        {

            outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());

        } else

        {

            outRect.set(0, 0, mDivider.getIntrinsicWidth(),

                    mDivider.getIntrinsicHeight());

        }

    }

}

效果：

android 5.0新特性学习--RecyclerView

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