实现纵向滚动
1，在app/build.gradle文件，dependencies中添加如下内容
----------------- compile ‘com.android.support:recyclerview-v7:24.2.1’ ------------------添加完点击Sync Now 进行同步 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-v7:24.2.1' compile 'com.android.support:recyclerview-v7:24.2.1' testCompile 'junit:junit:4.12' }
2，在MianActivity中添加RecyclerView控件，在指定一个自定义的布局fruit_item，
<?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/recycler_view" android:layout_width="match_parent" android:layout_height="match_parent"/> </LinearLayout>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_margin="5dp" > <ImageView android:id="@+id/fruit_item" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal"/> <TextView android:id="@+id/Tv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:layout_gravity="center_horizontal"/> </LinearLayout>
3，新建fruit 类，作为适配器的适配类型，就相当于给集合提供资源的，他是要添加进集合的。
public class Fruit { private String name ; private int imageId; public Fruit(int imageId, String name) { this.imageId = imageId; this.name = name; } public int getImageId() { return imageId; } public String getName() { return name; } }
4，创建RecyclerView的适配器类。
public class FruitAdapter extends RecyclerView.Adapter<FruitAdapter.ViewHolder>{ private List <Fruit> mFruitList; //内部类，继承自RecyclerView.ViewHolder //接收一个View ，通常就是RecyclerView子项的最外层布局， //所以就可以用findViewById 来获取控件 static class ViewHolder extends RecyclerView.ViewHolder{ ImageView imageView; TextView TextName; public ViewHolder(View View) { super(View); imageView = (ImageView)View.findViewById(R.id.fruit_item); TextName = (TextView) View.findViewById(R.id.Tv); } } //将要展示的数据传递进来， FruitAdapter(List<Fruit> list){ this.mFruitList = list ; } //将fruit_item 布局加载进来，然后创建一个ViewHolder实例， //将加载的布局传给ViewHolder的构造函数中。就可以获取布局中的控件 @Override public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.fruit_item,parent,false); ViewHolder holder = new ViewHolder(view); return holder; } //这个方法会在屏幕滚动的时候执行 // 通过position获取到Fruit 的实例，然后给布局上的控件进行赋值， @Override public void onBindViewHolder(FruitAdapter.ViewHolder holder, int position) { Fruit fruit = mFruitList.get(position); holder.imageView.setImageResource(fruit.getImageId()); holder.TextName.setText(fruit.getName()); } //他用于告诉RecyclerView有多少子项，直接返回数据源的长度就行了 @Override public int getItemCount() { return mFruitList.size(); } }
5，修改MainActivity代码，
public class MainActivity extends AppCompatActivity { List<Fruit> fruitList; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); fruitList = new ArrayList<>(); init(); RecyclerView recyclerView = (RecyclerView)findViewById(R.id.recycler_view); LinearLayoutManager layout = new LinearLayoutManager(this); recyclerView.setLayoutManager(layout); FruitAdapter adapter = new FruitAdapter(fruitList); recyclerView.setAdapter(adapter); } private void init() { for (int i = 0; i < 50; i++) { Fruit fruit = new Fruit(R.drawable.tab,"Name"+i); fruitList.add(fruit); } } }
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实现横向滚动
1,修改fruit_item中的代码，改变布局中排列方向，并设置居中。
<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/fruit_item" android:layout_width="wrap_content" android:layout_height="60dp" android:layout_gravity="center_horizontal"/> <TextView android:id="@+id/Tv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:layout_gravity="center_horizontal"/> </LinearLayout>
2，MainActivity只加入了一句话，调用LinearLayoutManager的setOrientation()方法来设置布局的排列方向默认是纵向排列，传入LinearLyoutManager.HORIZONTAL表示横向排列。
public class MainActivity extends AppCompatActivity { List<Fruit> fruitList; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); fruitList = new ArrayList<>(); init(); RecyclerView recyclerView = (RecyclerView)findViewById(R.id.recycler_view); LinearLayoutManager layout = new LinearLayoutManager(this); layout.setOrientation(LinearLayoutManager.HORIZONTAL);//设置为横向排列 recyclerView.setLayoutManager(layout); FruitAdapter adapter = new FruitAdapter(fruitList); recyclerView.setAdapter(adapter); } private void init() { for (int i = 0; i < 50; i++) { Fruit fruit = new Fruit(R.drawable.tab,"Name"+i); fruitList.add(fruit); } } }
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实现瀑布流
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1.修改fruit_item 中的代码，将宽度设置为match_parent,瀑布流的宽度是自己适配的，而不是一个固定值，其他的没有必要说了。
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_margin="5dp" > <ImageView android:id="@+id/fruit_item" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal"/> <TextView android:id="@+id/Tv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:layout_gravity="left"/> </LinearLayout>
2，修改MainActivity的代码，使用StaggeredGridLayoutManager就可以实现，为了让效果更好，我又加入了一个方法，创建一个随机数，让字符串多显示几遍，就可以明显的看到差别
public class MainActivity extends AppCompatActivity { List<Fruit> fruitList; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); fruitList = new ArrayList<>(); init(); RecyclerView recyclerView = (RecyclerView)findViewById(R.id.recycler_view); // LinearLayoutManager layout = new LinearLayoutManager(this); // layout.setOrientation(LinearLayoutManager.HORIZONTAL); // StaggeredGridLayoutManager的构造函数接收两个参数， / /第一个指定列数为3，第二个指定布局的排列方向 StaggeredGridLayoutManager layout = new StaggeredGridLayoutManager (3,StaggeredGridLayoutManager.VERTICAL); recyclerView.setLayoutManager(layout); FruitAdapter adapter = new FruitAdapter(fruitList); recyclerView.setAdapter(adapter); } private void init() { for (int i = 0; i < 50; i++) { Fruit fruit = new Fruit(R.drawable.tab,getRandomLengthName(i)); fruitList.add(fruit); } } private String getRandomLengthName(int i){ Random random = new Random() ; int Length = random.nextInt(20)+1 ; StringBuilder builder = new StringBuilder(); for (int j = 0 ;j<Length;j++){ builder.append("name"+i+" "); } return builder.toString(); } }
这样就实现了 纵向，横向和瀑布流的滚动布局！
