用RecyclerView实现水平滚动和网格视图

建立RecyclerViewActivity.java文件

 1 public class RecyclerViewActivity extends AppCompatActivity {
 2     private Button BtnLinear;
 3     private Button BtnShuiping;
 4     private Button BtnGrid;
 5     @Override
 6     protected void onCreate(Bundle savedInstanceState) {
 7         super.onCreate(savedInstanceState);
 8         setContentView(R.layout.activity_recycler_view);//遇到R标红问题时import class就好了
 9         BtnLinear=findViewById(R.id.btn_linear);
10         BtnShuiping=findViewById(R.id.btn_shuiping);
11         BtnGrid=findViewById(R.id.btn_grid);
12         BtnLinear.setOnClickListener(new View.OnClickListener() {
13             @Override
14             public void onClick(View view) {
15                 Intent intent=new Intent(RecyclerViewActivity.this,LinearRecyclerViewActivity.class);
16                 startActivity(intent);
17             }
18         });
19         BtnShuiping.setOnClickListener(new View.OnClickListener() {
20             @Override
21             public void onClick(View view) {
22                 Intent intent=new Intent(RecyclerViewActivity.this,ShuipRecyclerViewActivity.class);
23                 startActivity(intent);
24             }
25         });
26         BtnGrid.setOnClickListener(new View.OnClickListener() {
27             @Override
28             public void onClick(View view) {
29                 Intent intent=new Intent(RecyclerViewActivity.this,GridRecyclerViewActivity.class);
30                 startActivity(intent);
31             }
32         });
33     }
34 }

对应的activity_recycler_view.xml文件：

 1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     android:layout_width="match_parent"
 3     android:layout_height="wrap_content"
 4     android:orientation="vertical">
 5
 6     <Button
 7         android:id="@+id/btn_linear"
 8         android:layout_width="match_parent"
 9         android:layout_height="wrap_content"
10         android:text="列表视图">
11     </Button>
12
13     <Button
14         android:id="@+id/btn_shuiping"
15         android:layout_width="match_parent"
16         android:layout_height="wrap_content"
17         android:text="水平滚动"/>
18
19     <Button
20         android:id="@+id/btn_grid"
21         android:layout_width="match_parent"
22         android:layout_height="wrap_content"
23         android:text="网格视图">
24     </Button>
25
26
27 </LinearLayout>

实现水平滚动：

建立ShuipRecyclerViewActivity.java文件：

 1 public class ShuipRecyclerViewActivity extends AppCompatActivity {
 2     private RecyclerView RVshuip;
 3     @Override
 4     protected void onCreate(Bundle savedInstanceState) {
 5         super.onCreate(savedInstanceState);
 6         setContentView(R.layout.activity_shuip_recycler_view);
 7         RVshuip=findViewById(R.id.rv_shuip);
 8         LinearLayoutManager linearLayoutManager=new LinearLayoutManager(ShuipRecyclerViewActivity.this);
 9         linearLayoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);//注意linearLayoutManager的开头大小写，注意区分
10         RVshuip.setLayoutManager(linearLayoutManager);
11         RVshuip.addItemDecoration(new MyDecoration());
12         RVshuip.setAdapter(new ShuipAdapter(ShuipRecyclerViewActivity.this, new ShuipAdapter.OnItemClickListener() {
13             @Override
14             public void onClick(int pos) {
15                 Toast.makeText(ShuipRecyclerViewActivity.this, "点击"+pos, Toast.LENGTH_SHORT).show();
16             }
17         }));
18     }
19
20     class MyDecoration extends RecyclerView.ItemDecoration {
21         @Override
22         public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
23             super.getItemOffsets(outRect, view, parent, state);
24             outRect.set(getResources().getDimensionPixelOffset(R.dimen.deviderHeight), 0, 0, 0);
25         }//给列表视图在左面设置分隔线,记得在上面添加RVshuip.setLayoutManager(linearLayoutManager);这句话
26     }
27 }

对应的activity_shuip_recycler_view.xml文件：

 1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     android:layout_width="match_parent"
 3     android:layout_height="match_parent">
 4
 5     <androidx.recyclerview.widget.RecyclerView
 6         android:id="@+id/rv_shuip"
 7         android:layout_width="match_parent"
 8         android:layout_height="wrap_content"
 9         android:background="@color/greydrak"/>
10 </LinearLayout>

建立适配器ShuipAdapter.java文件：

 1 public class ShuipAdapter extends RecyclerView.Adapter<ShuipAdapter.LinearViewHolder>{
 2     private Context mcontext;
 3     private OnItemClickListener mlistener;
 4     public ShuipAdapter(Context context, OnItemClickListener listener){
 5         this.mcontext=context;
 6         this.mlistener=listener;
 7     }
 8     @NonNull
 9     @Override
10     public ShuipAdapter.LinearViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
11         return new LinearViewHolder(LayoutInflater.from(mcontext).inflate(R.layout.layout_shuip_item,parent,false));
12     }//这里原来是RecyclerView.ViewHolder，建立完LinearViewHolder class后要把它改成LinearAdapter.LinearViewHolder就可以了
13
14     @Override
15     public void onBindViewHolder(@NonNull ShuipAdapter.LinearViewHolder holder, int position) {
16         holder.textView.setText("大家好");
17         holder.itemView.setOnClickListener(new View.OnClickListener() {
18             @Override
19             public void onClick(View view) {
20                 //Toast.makeText(mcontext, "click...", Toast.LENGTH_SHORT).show();//第一种方法
21                 mlistener.onClick(position);//第二种方法，
22             }
23         });//增加点击事件，这是第一种方法
24     }//这里原来是RecyclerView.ViewHolder，建立完LinearViewHolder class后要把它改成LinearAdapter.LinearViewHolder就可以了
25
26     @Override
27     public int getItemCount() {
28         return 20;
29     }//设置有多少行
30
31     class LinearViewHolder extends RecyclerView.ViewHolder {
32         private TextView textView;
33         public LinearViewHolder(@NonNull View itemView) {
34             super(itemView);
35             textView=itemView.findViewById(R.id.tv_rtitle);
36         }
37     }
38     public interface OnItemClickListener{
39         void onClick(int pos);
40     }//点击事件的第二种方法，建立接口
41 }

最后是单个元素样式layout_shuip_item.xml文件：

 1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     android:layout_width="wrap_content"
 3     android:layout_height="wrap_content"
 4     android:orientation="vertical"
 5     android:background="@color/white"
 6     android:padding="10dp">
 7
 8     <TextView
 9         android:id="@+id/tv_rtitle"
10         android:layout_width="wrap_content"
11         android:layout_height="50dp"
12         android:gravity="center"
13         android:textColor="@color/black"
14         android:textSize="20sp"/>
15 </LinearLayout>

水平滚动效果：

实现网格视图：

建立GridRecyclerViewActivity.java文件：

 1 public class GridRecyclerViewActivity extends AppCompatActivity {
 2     private RecyclerView RVgrid;
 3     @Override
 4     protected void onCreate(Bundle savedInstanceState) {
 5         super.onCreate(savedInstanceState);
 6         setContentView(R.layout.activity_grid_recycler_view);
 7         RVgrid=findViewById(R.id.rv_grid);
 8         RVgrid.setLayoutManager(new GridLayoutManager(GridRecyclerViewActivity.this,3));//3是几列的意思
 9         RVgrid.setAdapter(new GridAdapter(GridRecyclerViewActivity.this, new GridAdapter.OnItemClickListener() {
10             @Override
11             public void onClick(int pos) {
12                 Toast.makeText(GridRecyclerViewActivity.this, "又点击了"+pos, Toast.LENGTH_SHORT).show();
13             }
14         }));
15     }
16 }

对应的activity_grid_recycler_view.xml文件:

1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
2     android:layout_width="match_parent"
3     android:layout_height="match_parent">
4     <androidx.recyclerview.widget.RecyclerView
5         android:id="@+id/rv_grid"
6         android:layout_width="match_parent"
7         android:layout_height="wrap_content"/>
8 </LinearLayout>

建立适配器GridAdapter.java文件：

 1 public class GridAdapter extends RecyclerView.Adapter<GridAdapter.LinearViewHolder>{
 2     private Context mcontext;
 3     private OnItemClickListener mlistener;
 4     public GridAdapter(Context context, OnItemClickListener listener){
 5         this.mcontext=context;
 6         this.mlistener=listener;
 7     }
 8     @NonNull
 9     @Override
10     public GridAdapter.LinearViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
11         return new LinearViewHolder(LayoutInflater.from(mcontext).inflate(R.layout.layout_grid_recyclerview_item,parent,false));
12     }//这里原来是RecyclerView.ViewHolder，建立完LinearViewHolder class后要把它改成LinearAdapter.LinearViewHolder就可以了
13
14     @Override
15     public void onBindViewHolder(@NonNull GridAdapter.LinearViewHolder holder, int position) {
16         holder.textView.setText("这是啥？！");
17         holder.itemView.setOnClickListener(new View.OnClickListener() {
18             @Override
19             public void onClick(View view) {
20                 //Toast.makeText(mcontext, "click...", Toast.LENGTH_SHORT).show();//第一种方法
21                 mlistener.onClick(position);//第二种方法，
22             }
23         });//增加点击事件，这是第一种方法
24     }//这里原来是RecyclerView.ViewHolder，建立完LinearViewHolder class后要把它改成LinearAdapter.LinearViewHolder就可以了
25
26     @Override
27     public int getItemCount() {
28         return 21;
29     }//设置有多少个
30
31     class LinearViewHolder extends RecyclerView.ViewHolder {
32         private TextView textView;
33         public LinearViewHolder(@NonNull View itemView) {
34             super(itemView);
35             textView=itemView.findViewById(R.id.tv_rtitle);
36         }
37     }
38     public interface OnItemClickListener{
39         void onClick(int pos);
40     }//点击事件的第二种方法，建立接口
41 }

最后是单个元素样式layout_grid_recyclerview_item.xml文件：

 1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     android:layout_width="wrap_content"
 3     android:layout_height="wrap_content"
 4     android:orientation="vertical"
 5     android:background="@color/white"
 6     android:padding="10dp">
 7
 8     <TextView
 9         android:id="@+id/tv_rtitle"
10         android:layout_width="wrap_content"
11         android:layout_height="50dp"
12         android:gravity="center"
13         android:textColor="@color/black"
14         android:textSize="20sp"/>
15 </LinearLayout>

网格视图效果：