public MediaAdapter(List<User> users){ mUsers = users; }标红
时间: 2023-12-03 19:47:13 浏览: 23
这段代码可能会出现问题,缺少类的声明语句。需要在代码文件开头加上`import`语句和类的声明语句。同时,如果`User`类不在当前文件的包中,还需要在`import`语句中指定其路径。例如:
```
import java.util.List;
import com.example.User;
public class MediaAdapter {
private List<User> mUsers;
public MediaAdapter(List<User> users){
mUsers = users;
}
}
```
相关问题
public List<User> selectUsers(Integer role, PageSort page) { log.info("批量查询用户信息,查询的角色权限:" + role); List<User> usersList = new ArrayList<User>(); int offset = (page.getPageNum() - 1) * page.getPageSize(); int limit = page.getPageSize(); RowBounds rowBounds = new RowBounds(offset, limit); List<User> userList = userInfoMapper.selectByRoleAndPage(role, rowBounds); return usersList; } @SelectProvider(type = UserSqlProvider.class, method = "selectByRoleAndPage") List<User> selectByRoleAndPage(@Param("role") Integer role, RowBounds rowBounds); public class UserSqlProvider { public String selectByRoleAndPage(Integer role, RowBounds rowBounds) { String sql = "SELECT * FROM user WHERE 1=1"; if (role != -1) { sql += " AND role = #{0}"; } sql += " LIMIT #{1.offset}, #{1.limit}"; return sql; } }方法selectByRoleAndPage没有关联上
selectUsers方法,应该在UserSqlProvider类中添加@Param注解来指定参数名称,如下所示:
```
public String selectByRoleAndPage(@Param("role") Integer role, @Param("rowBounds") RowBounds rowBounds) {
String sql = "SELECT * FROM user WHERE 1=1";
if (role != -1) {
sql += " AND role = #{role}";
}
sql += " LIMIT #{rowBounds.offset}, #{rowBounds.limit}";
return sql;
}
```
同时,在selectUsers方法中,应该将userList赋值给usersList,如下所示:
```
public List<User> selectUsers(Integer role, PageSort page) {
log.info("批量查询用户信息,查询的角色权限:" + role);
List<User> usersList = new ArrayList<User>();
int offset = (page.getPageNum() - 1) * page.getPageSize();
int limit = page.getPageSize();
RowBounds rowBounds = new RowBounds(offset, limit);
List<User> userList = userInfoMapper.selectByRoleAndPage(role, rowBounds);
usersList.addAll(userList);
return usersList;
}
```
List<User> users = (List<User>) myDB.getUserDao().getALLUsers();如何在activity的recycleview里引用room数据集
要在 `RecyclerView` 中显示 Room 数据库中的数据,您需要执行以下步骤:
1. 创建一个 `RecyclerView.Adapter` 类,并将 Room 数据库中的数据传递给该适配器。
2. 在 `onCreate()` 方法中,实例化适配器并将其设置到 `RecyclerView` 上。
下面是一个简单的示例代码:
```java
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {
private List<User> mUsers;
public MyAdapter(List<User> users) {
mUsers = users;
}
@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext())
.inflate(R.layout.item_user, parent, false);
return new ViewHolder(view);
}
@Override
public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
User user = mUsers.get(position);
holder.mTextViewName.setText(user.getName());
holder.mTextViewEmail.setText(user.getEmail());
}
@Override
public int getItemCount() {
return mUsers.size();
}
public static class ViewHolder extends RecyclerView.ViewHolder {
public TextView mTextViewName;
public TextView mTextViewEmail;
public ViewHolder(View itemView) {
super(itemView);
mTextViewName = itemView.findViewById(R.id.text_view_name);
mTextViewEmail = itemView.findViewById(R.id.text_view_email);
}
}
}
```
然后,在您的 `Activity` 中,您可以使用以下代码获取 Room 数据库中的数据并将其传递给适配器:
```java
List<User> users = myDB.getUserDao().getAllUsers();
MyAdapter adapter = new MyAdapter(users);
mRecyclerView.setAdapter(adapter);
```
这里,我们首先从 Room 数据库中获取所有用户数据,然后实例化一个适配器并将该数据传递给它。最后,我们将适配器设置到 `RecyclerView` 上。
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