為方便自己以后學習,自己記錄學習,大家也可以參考,有什么問題一起探討。
今天學習RecyclerView,下邊來說一下實現(xiàn)數(shù)據(jù)垂直滾動和數(shù)據(jù)橫向滾動。先上圖為敬:
所用工具:Android Studio
縱向滾動
1、添加依賴庫:
打開app/build.gradle文件,在dependencies閉包中添加如下內(nèi)容(compile 'com.android.support:recyclerview-v7:24.2.1'為添加的內(nèi)容)
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'}
添加完之后點擊一下Sync Now來進行同步;
2、修改activity_main.xml中的代碼:
<?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>
因為RecyclerView不是內(nèi)置在系統(tǒng)SDK中的,所以需要把完整的包路徑寫出來。
3、新建實體類,這里以Book類作為演示:
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、為ListView的子項制定一個我們自定義的布局:
在layout目錄下新建book_item.xml
<?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、為RecyclerView準備一個適配器:
新建BookAdapter類,讓這個類繼承RecyclerView.Adapter,并將泛型指定為BookAdapter.ViewHolder;
里邊自定義一個內(nèi)部類ViewHolder,里邊的構(gòu)造參數(shù)傳入view參數(shù),這個參數(shù)就是RecyclerView的最外層布局,這樣就可以通過findViewById()來貨渠道布局中的ImageView和TextView的實例了;
BookAdapter中的構(gòu)造函數(shù),這個方法吧要展示的數(shù)據(jù)源傳進來,并賦值給一個全局變量mBookAdapter,我們后繼的所有操作都將在這個數(shù)據(jù)源的基礎上進行;重寫三個方法;
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中的代碼:
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中定制了可擴展的布局排列接口,子類按照接口中的規(guī)范來實現(xiàn)就可以定制出不同排雷方式的布局了 //配置布局,默認為vertical(垂直布局),下邊這句將布局改為水平布局 //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); } }}
此時運行即可看到縱向的展示樣例了。
實現(xiàn)橫向滾動:
修改book_item中的代碼:
<?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中的代碼
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中定制了可擴展的布局排列接口,子類按照接口中的規(guī)范來實現(xiàn)就可以定制出不同排雷方式的布局了 //配置布局,默認為vertical(垂直布局),下邊這句將布局改為水平布局 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); } }}
例子下載地址:RecyclerView實現(xiàn)縱向和橫向滾動
以上就是本文的全部內(nèi)容,希望對大家的學習有所幫助,也希望大家多多支持VEVB武林網(wǎng)。
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