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今天学习RecyclerView,下边来说一下实现数据垂直滚动和数据横向滚动。先上图为敬:
所用工具:Android Studio
纵向滚动
1、添加依赖库:
打开app/build.gradle文件,在dependencies闭包中添加如下内容(compile 'com.android.support:recyclerview-v7:24.2.1'为添加的内容)
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dependencies { compile fileTree(dir: 'libs' , include: [ '*.jar' ]) androidTestCompile( 'com.android.support.test.espresso:espresso-core:2.2.2' , { exclude group: 'com.android.support' , module: 'support-annotations' }) compile 'com.android.support:appcompat-v7:26.0.0-alpha1' compile 'com.android.support:recyclerview-v7:24.2.1' testCompile 'junit:junit:4.12' } |
添加完之后点击一下Sync Now来进行同步;
2、修改activity_main.xml中的代码:
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<? xml version = "1.0" encoding = "utf-8" ?> < LinearLayout 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.dell.practice_recyclerview.MainActivity" > < android.support.v7.widget.RecyclerView android:id = "@+id/id_recycler_view" android:layout_width = "match_parent" android:layout_height = "match_parent" > </ android.support.v7.widget.RecyclerView > </ LinearLayout > |
因为RecyclerView不是内置在系统SDK中的,所以需要把完整的包路径写出来。
3、新建实体类,这里以Book类作为演示:
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package com.example.dell.practice_recyclerview; /** * Created by dell on 2018/6/3. * Created by qiyueqing on 2018/6/3. */ public class Book { private String name; private int imageId; public Book(String name, int imageId) { this .name = name; this .imageId = imageId; } public String getName() { return name; } public int getImageId() { return imageId; } } |
4、为ListView的子项制定一个我们自定义的布局:
在layout目录下新建book_item.xml
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<? 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 = "wrap_content" > < ImageView android:id = "@+id/id_book_image" android:layout_width = "wrap_content" android:layout_height = "wrap_content" /> < TextView android:id = "@+id/id_book_name" android:layout_width = "wrap_content" android:layout_height = "wrap_content" android:layout_gravity = "center_vertical" android:layout_marginLeft = "10dp" /> </ LinearLayout > |
5、为RecyclerView准备一个适配器:
新建BookAdapter类,让这个类继承RecyclerView.Adapter,并将泛型指定为BookAdapter.ViewHolder;
里边自定义一个内部类ViewHolder,里边的构造参数传入view参数,这个参数就是RecyclerView的最外层布局,这样就可以通过findViewById()来货渠道布局中的ImageView和TextView的实例了;
BookAdapter中的构造函数,这个方法吧要展示的数据源传进来,并赋值给一个全局变量mBookAdapter,我们后继的所有操作都将在这个数据源的基础上进行;重写三个方法;
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package com.example.dell.practice_recyclerview; import android.support.v7.widget.RecyclerView; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.ImageView; import android.widget.TextView; import java.util.List; /** * Created by dell on 2018/6/3. * Created by qiyueqing on 2018/6/3. */ public class BookAdapter extends RecyclerView.Adapter<BookAdapter.ViewHolder>{ private List<Book> mBookList; static class ViewHolder extends RecyclerView.ViewHolder{ ImageView bookImage; TextView bookName; public ViewHolder(View view){ super (view); bookImage=view.findViewById(R.id.id_book_image); bookName=view.findViewById(R.id.id_book_name); } } public BookAdapter(List<Book> bookList){ mBookList=bookList; } @Override public BookAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.book_item,parent, false ); RecyclerView.ViewHolder holder= new ViewHolder(view); return (ViewHolder) holder; } @Override public void onBindViewHolder(BookAdapter.ViewHolder holder, int position) { Book book=mBookList.get(position); holder.bookImage.setImageResource(book.getImageId()); holder.bookName.setText(book.getName()); } @Override public int getItemCount() { return mBookList.size(); } } |
6、修改MainActivity中的代码:
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package com.example.dell.practice_recyclerview; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.support.v7.widget.LinearLayoutManager; import android.support.v7.widget.RecyclerView; import java.util.ArrayList; import java.util.List; public class MainActivity extends AppCompatActivity { private List<Book> bookList= new ArrayList<>(); protected void onCreate(Bundle savedInstanceState) { super .onCreate(savedInstanceState); setContentView(R.layout.activity_main); initBooks(); RecyclerView recyclerView= (RecyclerView) findViewById(R.id.id_recycler_view); LinearLayoutManager layoutManager= new LinearLayoutManager( this ); //LinearLayoutManager中定制了可扩展的布局排列接口,子类按照接口中的规范来实现就可以定制出不同排雷方式的布局了 //配置布局,默认为vertical(垂直布局),下边这句将布局改为水平布局 //layoutManager.setOrientation(LinearLayoutManager.HORIZONTAL); recyclerView.setLayoutManager(layoutManager); BookAdapter adapter= new BookAdapter(bookList); recyclerView.setAdapter(adapter); } private void initBooks(){ for ( int i= 1 ;i< 11 ;i++){ Book book= new Book( "春起之苗" +i,R.drawable.icon_book); bookList.add(book); } } } |
此时运行即可看到纵向的展示样例了。
实现横向滚动:
修改book_item中的代码:
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<? xml version = "1.0" encoding = "utf-8" ?> < LinearLayout xmlns:android = "http://schemas.android.com/apk/res/android" android:orientation = "vertical" android:layout_width = "100dp" android:layout_height = "wrap_content" > < ImageView android:id = "@+id/id_book_image" android:layout_width = "wrap_content" android:layout_height = "wrap_content" android:layout_gravity = "center_horizontal" /> < TextView android:id = "@+id/id_book_name" android:layout_width = "wrap_content" android:layout_height = "wrap_content" android:layout_gravity = "center_horizontal" android:layout_marginLeft = "10dp" /> </ LinearLayout > |
2、修改MainActivity中的代码
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package com.example.dell.practice_recyclerview; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.support.v7.widget.LinearLayoutManager; import android.support.v7.widget.RecyclerView; import java.util.ArrayList; import java.util.List; public class MainActivity extends AppCompatActivity { private List<Book> bookList= new ArrayList<>(); protected void onCreate(Bundle savedInstanceState) { super .onCreate(savedInstanceState); setContentView(R.layout.activity_main); initBooks(); RecyclerView recyclerView= (RecyclerView) findViewById(R.id.id_recycler_view); LinearLayoutManager layoutManager= new LinearLayoutManager( this ); //LinearLayoutManager中定制了可扩展的布局排列接口,子类按照接口中的规范来实现就可以定制出不同排雷方式的布局了 //配置布局,默认为vertical(垂直布局),下边这句将布局改为水平布局 layoutManager.setOrientation(LinearLayoutManager.HORIZONTAL); recyclerView.setLayoutManager(layoutManager); BookAdapter adapter= new BookAdapter(bookList); recyclerView.setAdapter(adapter); } private void initBooks(){ for ( int i= 1 ;i< 11 ;i++){ Book book= new Book( "春起之苗" +i,R.drawable.icon_book); bookList.add(book); } } } |
例子下载地址:RecyclerView实现纵向和横向滚动
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持服务器之家。
原文链接:https://blog.csdn.net/easy_purple/article/details/80558009