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);
}
}
}
*
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);
}
}
}
**
实现瀑布流
**
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();
}
}