Question

如果我的recyclerView没有加载，我试图将TextView设置为空视图，并且我无法使setEmptyView工作。它说无法解析方法setEmptyView。这是代码：

@EnableWebSecurity
@Configuration
public class RetailerSecurityConfig extends WebSecurityConfigurerAdapter {
    @Override
    protected void configure(HttpSecurity http) throws Exception {

        http
                .csrf().ignoringAntMatchers("/login/**")
                .and()
                .authorizeRequests()
                .antMatchers("/login", "/login/reset", "/resources/**", "/balance/getResult/**").permitAll()
                .antMatchers("/retailers/**", "/balance/**").access("hasRole('ROLE_ADMIN')")
                .antMatchers("/tellers/**", "/tellers").hasAnyAuthority("PRIMARY")
                .antMatchers("/sell/**", "/sell").hasAnyAuthority("TELLER")
                .anyRequest().fullyAuthenticated()
                .and()
                .formLogin()
                .loginPage("/login")
                .successForwardUrl("/login/success")
                .permitAll()
                .and()
                .logout()
                .permitAll();

    }
}

我在片段中，这可能是为什么？

Answer 1

RecyclerView不支持setEmptyView。可以使用这个类。

public class RecyclerViewEmptyView extends RecyclerView {
    private View emptyView;

    private AdapterDataObserver emptyObserver = new AdapterDataObserver() {


        @Override
        public void onChanged() {
            Adapter<?> adapter =  getAdapter();
            if(adapter != null && emptyView != null) {
                if(adapter.getItemCount() == 0) {
                    emptyView.setVisibility(View.VISIBLE);
                    RecyclerViewEmptySupport.this.setVisibility(View.GONE);
                }
                else {
                    emptyView.setVisibility(View.GONE);
                    RecyclerViewEmptySupport.this.setVisibility(View.VISIBLE);
                }
            }

        }
    };

    public RecyclerViewEmptySupport(Context context) {
        super(context);
    }

    public RecyclerViewEmptySupport(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public RecyclerViewEmptySupport(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    public void setAdapter(Adapter adapter) {
        super.setAdapter(adapter);

        if(adapter != null) {
            adapter.registerAdapterDataObserver(emptyObserver);
        }

        emptyObserver.onChanged();
    }

    public void setEmptyView(View emptyView) {
        this.emptyView = emptyView;
    }
}

或者你可以

<android.support.v7.widget.RecyclerView
    android:id="@+id/recycler_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:scrollbars="vertical" />

<TextView
    android:id="@+id/empty_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:visibility="gone"
    android:text="No Data Available" />

Java代码：

private RecyclerView recyclerView;
private TextView emptyView;

// ...

recyclerView = (RecyclerView) rootView.findViewById(R.id.recycler_view);
emptyView = (TextView) rootView.findViewById(R.id.empty_view);

// ...

if (dataset.isEmpty()) {
    recyclerView.setVisibility(View.GONE);
    emptyView.setVisibility(View.VISIBLE);
}
else {
    recyclerView.setVisibility(View.VISIBLE);
    emptyView.setVisibility(View.GONE);
}

Answer 2

首先，您必须将xml中的emptyView设置为android:visibility="gone"。

<TextView
    android:id="@+id/empty_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:visibility="gone"
    android:text="There is no item" />

其次，如果您检索的数据集为空，则必须将recyclerview的可见性设置为已消失。

private RecyclerView recyclerViewUser1 ;
private TextView emptyStateTextView ;

// ...

recyclerViewUser1 = (RecyclerView) rootView.findViewById(R.id.recycler_view_red_room1);
emptyStateTextView = (TextView) rootView.findViewById(R.id.empty_view);

// ...

if (dataset.isEmpty()) {
    recyclerViewUser1 .setVisibility(View.GONE);
    emptyStateTextView .setVisibility(View.VISIBLE);
}
else {
    recyclerViewUser1 .setVisibility(View.VISIBLE);
    emptyStateTextView .setVisibility(View.GONE);
}

无法解析方法setEmptyView

2 个答案: