RecyclerView

话说RecyclerView已经出生非常长时间了特点和ListView,GridView类似。

长处是：（使用更加灵活、item能够直接使用动画等..）那么今天開始我们来重点学习一下RecyclerView控件。以下直接上代码：

1. 创建一个新项目

1.在Android studio中，通过 File ⇒ New Project

2.加入依赖   

build.gradle
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
testCompile 'junit:junit:4.12'
compile 'com.android.support:appcompat-v7:23.1.1'
compile 'com.android.support:design:23.1.1'
compile 'com.android.support:recyclerview-v7:23.1.1'
}

3.默认会有两个文件activity_main.xml(CoordinatorLayout、AppBarLayout)和content_main.xml(项目用到的内容)

content_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"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:showIn="@layout/activity_main"
<div style="text-align: left;"></div>tools:context=".MainActivity">

<android.support.v7.widget.RecyclerView
android:id="@+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:scrollbars="vertical" />
</RelativeLayout>

4.打开colors.xml位置在res ⇒ values

colors.xml
<?xml version="1.0" encoding="utf-8"?
>
<resources>
<color name="colorPrimary">#3F51B5</color>
<color name="colorPrimaryDark">#303F9F</color>
<color name="colorAccent">#FF4081</color>
<color name="year">#999999</color>
<color name="title">#222222</color>
</resources>

2.写适配器

5.自己定义一个实体类

Movie.java
package info.androidhive.recyclerview;

public class Movie {
private String title, genre, year;

public Movie() {
}

public Movie(String title, String genre, String year) {
this.title = title;
this.genre = genre;
this.year = year;
}

public String getTitle() {
return title;
}

public void setTitle(String name) {
this.title = name;
}

public String getYear() {
return year;
}

public void setYear(String year) {
this.year = year;
}

public String getGenre() {
return genre;
}

public void setGenre(String genre) {
this.genre = genre;
}
}

6.创建一个movie_list_row.xml在Layout文件夹。这个文件用于在RecyclerView中显示用到的item

movie_list_row.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="wrap_content"
android:focusable="true"
android:paddingLeft="16dp"
android:paddingRight="16dp"
android:paddingTop="10dp"
android:paddingBottom="10dp"
android:clickable="true"
android:background="?android:attr/selectableItemBackground"
android:orientation="vertical">

<TextView
android:id="@+id/title"
android:textColor="@color/title"
android:textSize="16dp"
android:textStyle="bold"
android:layout_alignParentTop="true"
android:layout_width="match_parent"
android:layout_height="wrap_content" />

<TextView
android:id="@+id/genre"
android:layout_below="@id/title"
android:layout_width="match_parent"
android:layout_height="wrap_content" />

<TextView
android:id="@+id/year"
android:textColor="@color/year"
android:layout_width="wrap_content"
android:layout_alignParentRight="true"
android:layout_height="wrap_content" />

</RelativeLayout>

7.如今创建类MoviesAdapter加入下面代码。

HereonCreateViewHolder()方法用于载入movie_list_row.xml.在onBindViewHolder()为了适配数据（title, genre和year)

MoviesAdapter.java
package info.androidhive.recyclerview;

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 MoviesAdapter extends RecyclerView.Adapter<MoviesAdapter.MyViewHolder> {

private List<Movie> moviesList;

public class MyViewHolder extends RecyclerView.ViewHolder {
public TextView title, year, genre;

public MyViewHolder(View view) {
super(view);
title = (TextView) view.findViewById(R.id.title);
genre = (TextView) view.findViewById(R.id.genre);
year = (TextView) view.findViewById(R.id.year);
}
}


public MoviesAdapter(List<Movie> moviesList) {
this.moviesList = moviesList;
}

@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.movie_list_row, parent, false);

return new MyViewHolder(itemView);
}

@Override
public void onBindViewHolder(MyViewHolder holder, int position) {
Movie movie = moviesList.get(position);
holder.title.setText(movie.getTitle());
holder.genre.setText(movie.getGenre());
holder.year.setText(movie.getYear());
}

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

8.打开MainActivity做下面改变，prepareMovieData()这种方法加入了一些数据在列表中.

MainActivity.java
package info.androidhive.recyclerview;

import android.content.Context;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Toast;

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

public class MainActivity extends AppCompatActivity {
private List<Movie> movieList = new ArrayList<>();
private RecyclerView recyclerView;
private MoviesAdapter mAdapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);

recyclerView = (RecyclerView) findViewById(R.id.recycler_view);

mAdapter = new MoviesAdapter(movieList);
RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getApplicationContext());
recyclerView.setLayoutManager(mLayoutManager);
recyclerView.setItemAnimator(new DefaultItemAnimator());
recyclerView.setAdapter(mAdapter);

prepareMovieData();
}

private void prepareMovieData() {
Movie movie = new Movie("Mad Max: Fury Road", "Action & Adventure", "2015");
movieList.add(movie);

movie = new Movie("Inside Out", "Animation, Kids & Family", "2015");
movieList.add(movie);

movie = new Movie("Star Wars: Episode VII - The Force Awakens", "Action", "2015");
movieList.add(movie);

movie = new Movie("Shaun the Sheep", "Animation", "2015");
movieList.add(movie);

movie = new Movie("The Martian", "Science Fiction & Fantasy", "2015");
movieList.add(movie);

movie = new Movie("Mission: Impossible Rogue Nation", "Action", "2015");
movieList.add(movie);

movie = new Movie("Up", "Animation", "2009");
movieList.add(movie);

movie = new Movie("Star Trek", "Science Fiction", "2009");
movieList.add(movie);

movie = new Movie("The LEGO Movie", "Animation", "2014");
movieList.add(movie);

movie = new Movie("Iron Man", "Action & Adventure", "2008");
movieList.add(movie);

movie = new Movie("Aliens", "Science Fiction", "1986");
movieList.add(movie);

movie = new Movie("Chicken Run", "Animation", "2000");
movieList.add(movie);

movie = new Movie("Back to the Future", "Science Fiction", "1985");
movieList.add(movie);

movie = new Movie("Raiders of the Lost Ark", "Action & Adventure", "1981");
movieList.add(movie);

movie = new Movie("Goldfinger", "Action & Adventure", "1965");
movieList.add(movie);

movie = new Movie("Guardians of the Galaxy", "Science Fiction & Fantasy", "2014");
movieList.add(movie);

mAdapter.notifyDataSetChanged();
}
}

这是我的执行结果：

3.给你的RecyclerView加入切割线

 

9.创建DividerItemDecoration

DividerItemDecoration.java
package info.androidhive.recyclerview;
 
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.view.View;
 
/**
 * Created by Lincoln on 30/10/15.
 */
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 onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
        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);
            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, View view, RecyclerView parent, RecyclerView.State state) {
        if (mOrientation == VERTICAL_LIST) {
            outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
        } else {
            outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
        }
    }
}

10.打开MainActivity通过addItemDecoration（）方法为item加入切割线

recyclerView.addItemDecoration(new DividerItemDecoration(this, LinearLayoutManager.VERTICAL));
 
// set the adapter
recyclerView.setAdapter(mAdapter);

 我的App执行结果是：

 

4.为RecyclerView Item 加入点击事件

RecyclerView 默认没有OnItemClickListener方法。我们须要自己写;RecyclerView.OnItemTouchListener

11.在MainActivity加入RecyclerTouchListener类，ClickListener接口

MainActivity.java
public interface ClickListener {
        void onClick(View view, int position);
 
        void onLongClick(View view, int position);
    }
 
    public static class RecyclerTouchListener implements RecyclerView.OnItemTouchListener {
 
        private GestureDetector gestureDetector;
        private MainActivity.ClickListener clickListener;
 
        public RecyclerTouchListener(Context context, final RecyclerView recyclerView, final MainActivity.ClickListener clickListener) {
            this.clickListener = clickListener;
            gestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener() {
                @Override
                public boolean onSingleTapUp(MotionEvent e) {
                    return true;
                }
 
                @Override
                public void onLongPress(MotionEvent e) {
                    View child = recyclerView.findChildViewUnder(e.getX(), e.getY());
                    if (child != null && clickListener != null) {
                        clickListener.onLongClick(child, recyclerView.getChildPosition(child));
                    }
                }
            });
        }
 
        @Override
        public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
 
            View child = rv.findChildViewUnder(e.getX(), e.getY());
            if (child != null && clickListener != null && gestureDetector.onTouchEvent(e)) {
                clickListener.onClick(child, rv.getChildPosition(child));
            }
            return false;
        }
 
        @Override
        public void onTouchEvent(RecyclerView rv, MotionEvent e) {
        }
 
        @Override
        public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
 
        }
    }

最后为RecyClerView加入监听

recyclerView.addOnItemTouchListener(new RecyclerTouchListener(getApplicationContext(), recyclerView, new ClickListener() {
            @Override
            public void onClick(View view, int position) {
                Movie movie = movieList.get(position);
                Toast.makeText(getApplicationContext(), movie.getTitle() + " is selected!", Toast.LENGTH_SHORT).show();
            }
 
            @Override
            public void onLongClick(View view, int position) {
 
            }
        }));

如今你能够验证点击事件了，我的执行结果:

最后贴出Activity全部代码：

package info.androidhive.recyclerview;
 
import android.content.Context;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Toast;
 
import java.util.ArrayList;
import java.util.List;
 
public class MainActivity extends AppCompatActivity {
    private List<Movie> movieList = new ArrayList<>();
    private RecyclerView recyclerView;
    private MoviesAdapter mAdapter;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
 
        recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
 
        mAdapter = new MoviesAdapter(movieList);
 
        recyclerView.setHasFixedSize(true);
        RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getApplicationContext());
        recyclerView.setLayoutManager(mLayoutManager);
        recyclerView.addItemDecoration(new DividerItemDecoration(this, LinearLayoutManager.VERTICAL));
        recyclerView.setItemAnimator(new DefaultItemAnimator());
        recyclerView.setAdapter(mAdapter);
 
        recyclerView.addOnItemTouchListener(new RecyclerTouchListener(getApplicationContext(), recyclerView, new ClickListener() {
            @Override
            public void onClick(View view, int position) {
                Movie movie = movieList.get(position);
                Toast.makeText(getApplicationContext(), movie.getTitle() + " is selected!", Toast.LENGTH_SHORT).show();
            }
 
            @Override
            public void onLongClick(View view, int position) {
 
            }
        }));
 
        prepareMovieData();
    }
 
    private void prepareMovieData() {
        Movie movie = new Movie("Mad Max: Fury Road", "Action & Adventure", "2015");
        movieList.add(movie);
 
        movie = new Movie("Inside Out", "Animation, Kids & Family", "2015");
        movieList.add(movie);
 
        movie = new Movie("Star Wars: Episode VII - The Force Awakens", "Action", "2015");
        movieList.add(movie);
 
        movie = new Movie("Shaun the Sheep", "Animation", "2015");
        movieList.add(movie);
 
        movie = new Movie("The Martian", "Science Fiction & Fantasy", "2015");
        movieList.add(movie);
 
        movie = new Movie("Mission: Impossible Rogue Nation", "Action", "2015");
        movieList.add(movie);
 
        movie = new Movie("Up", "Animation", "2009");
        movieList.add(movie);
 
        movie = new Movie("Star Trek", "Science Fiction", "2009");
        movieList.add(movie);
 
        movie = new Movie("The LEGO Movie", "Animation", "2014");
        movieList.add(movie);
 
        movie = new Movie("Iron Man", "Action & Adventure", "2008");
        movieList.add(movie);
 
        movie = new Movie("Aliens", "Science Fiction", "1986");
        movieList.add(movie);
 
        movie = new Movie("Chicken Run", "Animation", "2000");
        movieList.add(movie);
 
        movie = new Movie("Back to the Future", "Science Fiction", "1985");
        movieList.add(movie);
 
        movie = new Movie("Raiders of the Lost Ark", "Action & Adventure", "1981");
        movieList.add(movie);
 
        movie = new Movie("Goldfinger", "Action & Adventure", "1965");
        movieList.add(movie);
 
        movie = new Movie("Guardians of the Galaxy", "Science Fiction & Fantasy", "2014");
        movieList.add(movie);
 
        mAdapter.notifyDataSetChanged();
    }
 
    public interface ClickListener {
        void onClick(View view, int position);
 
        void onLongClick(View view, int position);
    }
 
    public static class RecyclerTouchListener implements RecyclerView.OnItemTouchListener {
 
        private GestureDetector gestureDetector;
        private MainActivity.ClickListener clickListener;
 
        public RecyclerTouchListener(Context context, final RecyclerView recyclerView, final MainActivity.ClickListener clickListener) {
            this.clickListener = clickListener;
            gestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener() {
                @Override
                public boolean onSingleTapUp(MotionEvent e) {
                    return true;
                }
 
                @Override
                public void onLongPress(MotionEvent e) {
                    View child = recyclerView.findChildViewUnder(e.getX(), e.getY());
                    if (child != null && clickListener != null) {
                        clickListener.onLongClick(child, recyclerView.getChildPosition(child));
                    }
                }
            });
        }
 
        @Override
        public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
 
            View child = rv.findChildViewUnder(e.getX(), e.getY());
            if (child != null && clickListener != null && gestureDetector.onTouchEvent(e)) {
                clickListener.onClick(child, rv.getChildPosition(child));
            }
            return false;
        }
 
        @Override
        public void onTouchEvent(RecyclerView rv, MotionEvent e) {
        }
 
        @Override
        public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
 
        }
    }
 
}