Question

我是学生，是Android新手，我从课程中获得了这段代码，该代码显示了已插入资源（xml文件）的数组到2个片段。但是，如何显示数据库中的数据？

我想显示由失败状态造成短路的课程数据，如果数据库中的状态课程为1，则该课程显示在“通过”选项卡中，其他所有内容都将进入“失败”选项卡

这是 CourseListAdapter ：

public class CourseListAdapter extends RecyclerView.Adapter<CourseListAdapter.ViewHolder> {

    private Context cCtx;
    private List<Course> cData = new ArrayList<>();
    private OnItemClickListener cOnItemClickListener;

    public interface OnItemClickListener {
        void onItemClick(View view, Course crs, int position);
    }

    public void setOnItemClickListener(final OnItemClickListener cItemClickListener) {
        this.cOnItemClickListener = cItemClickListener;
    }

    public class ViewHolder extends RecyclerView.ViewHolder {
        public TextView status;
        public TextView cname;
        public TextView courseid;
        public View layout_cparent;

        public ViewHolder(View v) {
            super(v);
            status = (TextView) v.findViewById(R.id.status);
            cname = (TextView) v.findViewById(R.id.cname);
            courseid = (TextView) v.findViewById(R.id.courseid);
            layout_cparent = (View) v.findViewById(R.id.layout_cparent);
        }

    }

    public CourseListAdapter(Context cCtx, List<Course> cData) {
        this.cCtx= cCtx;
        this.cData= cData;
    }

    @Override
    public CourseListAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_booking, parent, false);
        ViewHolder vh = new ViewHolder(v);
        return vh;
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, final int position) {
        final Course c = cData.get(position);

        holder.cname.setText(c.cname);
        holder.courseid.setText(c.courseid);

        holder.status.setText(c.status);
        if (c.status.equals("0")) {
            holder.status.setBackgroundDrawable(cCtx.getResources().getDrawable(R.drawable.cfail));
        } else if (c.status.equals("1")) {
            holder.status.setBackgroundDrawable(cCtx.getResources().getDrawable(R.drawable.credo));
        } else if (b.status.equals("2")) {
            holder.status.setBackgroundDrawable(cCtx.getResources().getDrawable(R.drawable.cpass));
        }

        holder.layout_cparent.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (cOnItemClickListener != null) {
                    cOnItemClickListener.onItemClick(view, c, position);
                }
            }
        });
    }

    @Override
    public int getItemCount() {
        return data.size();
    }

    @Override
    public long getItemId(int position) {
        return position;
    }
}

这是模型课程：

public class Course implements Serializable {
public String status;
public String cname;
public String courseid;

}

这是获取数据的常量类，我假设这是从虚拟数组字符串中获取数据的类。我试图在此类中添加我的JSON请求，但出现“静态”错误。

常数：

private static List<Course> getCourse(Context cCtx) {
        List<Course> data = new ArrayList<>();
        String[] status = cCtx.getResources().getStringArray(R.array.dummy_course_status);
        String[] cname = cCtx.getResources().getStringArray(R.array.dummy_course_name);
        String[] courseid = cCtx.getResources().getStringArray(R.array.dummy_course_id);

        for (int i = 0; i < status.length; i++) {
            Course item = new Course();
            item.status = status[i];
            item.cname= cname[i];
            item.courseid = courseid[i];
            data.add(item);
        }
        return data;
    }

    public static List<Course> getCoursePass(Context ctx) {
        return getCourse(ctx).subList(0, 1);
    }

    public static List<Course> getCourseFailed(Context ctx) {
        String[] status = ctx.getResources().getStringArray(R.array.dummy_course_status);
        return getCourse(ctx).subList(1, status.length);
    }

这是 FragmentCoursePass ：

public class FragmentCoursePass extends Fragment {

    private View rootView;
    private RecyclerView recyclerView;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        rootView = inflater.inflate(R.layout.fragment_course_pass, container, false);
        initComponent();
        return rootView;
    }

    private void initComponent() {
        recyclerView = (RecyclerView) rootView.findViewById(R.id.recyclerView);
        recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
        recyclerView.setHasFixedSize(true);

        List<Course> courseList = Constant.getCoursePass(getActivity());
        CourseListAdapter cAdapter = new CourseListAdapter(getActivity(), courseList);
        recyclerView.setAdapter(cAdapter);

        cAdapter.setOnItemClickListener(new CourseListAdapter.OnItemClickListener() {
            @Override
            public void onItemClick(View view, Course crs, int position) {
                ActivityCoursePassDetails.navigate(getActivity(), crs);
            }
        });
    }

    @Override
    public void onResume() {
        super.onResume();
    }

}

FragmentCourseFailed 几乎相同，只是变量不同

此外，这是 ActivityCourse ：

public class ActivityCourse extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_course);
        initComponent();
        initToolbar();
    }


    private void initComponent() {
        ViewPager view_pager = (ViewPager) findViewById(R.id.view_pager);
        FragmentAdapter adapter = new FragmentAdapter(getSupportFragmentManager());

        FragmentCoursePass fragmentCoursePass = new FragmentCoursePass();
        FragmentCourseFailed fragmentCourseFailed = new FragmentCourseFailed();

        adapter.addFragment(fragmentCoursePass, "PASS");
        adapter.addFragment(fragmentCourseFailed, "FAIL");

        view_pager.setAdapter(adapter);

        TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
        tabLayout.setupWithViewPager(view_pager);
    }

    private void initToolbar() {
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        ActionBar actionBar = getSupportActionBar();
        actionBar.setTitle("Order");
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        Tools.setCompleteSystemBarLight(this);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if (item.getItemId() == android.R.id.home) {
            onBackPressed();
        } else {
            Toast.makeText(getApplicationContext(), item.getTitle(), Toast.LENGTH_SHORT).show();
        }
        return super.onOptionsItemSelected(item);
    }

    public class FragmentAdapter extends FragmentPagerAdapter {

        private final List<Fragment> mFragments = new ArrayList<>();
        private final List<String> mFragmentTitles = new ArrayList<>();

        public FragmentAdapter(FragmentManager fm) {
            super(fm);
        }

        public void addFragment(Fragment fragment, String title) {
            mFragments.add(fragment);
            mFragmentTitles.add(title);
        }

        @Override
        public Fragment getItem(int position) {
            return mFragments.get(position);
        }


        @Override
        public int getCount() {
            return mFragments.size();
        }

        @Override
        public CharSequence getPageTitle(int position) {
            return mFragmentTitles.get(position);
        }
    }

这是布局，我有几个具有textview来容纳字符串的布局

activity_course.xml ：

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/main_content"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/grey_bg"
    android:fitsSystemWindows="true">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/appbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="@android:color/white"
            app:contentInsetStartWithNavigation="0dp"
            app:layout_scrollFlags="scroll|enterAlways"
            app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
            app:theme="@style/Toolbar.Light" />

        <android.support.design.widget.TabLayout
            android:id="@+id/tab_layout"
            android:layout_width="match_parent"
            android:layout_height="45dp"
            android:background="@android:color/white"
            app:tabGravity="fill"
            app:tabIndicatorColor="@color/colorPrimary"
            app:tabIndicatorHeight="3dp"
            app:tabSelectedTextColor="@color/grey_very_hard"
            app:tabTextAppearance="@style/CustomTabTextAppearance"
            app:tabTextColor="@color/grey_very_hard" />

    </android.support.design.widget.AppBarLayout>

    <android.support.v4.view.ViewPager
        android:id="@+id/view_pager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior" />

</android.support.design.widget.CoordinatorLayout>

这是 fragment_course_pass.xml ：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/grey_bg">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:clipToPadding="false"
        android:paddingTop="@dimen/spacing_middle"
        android:paddingBottom="@dimen/spacing_middle"
        android:scrollbars="none"
        android:scrollingCache="true" />

</RelativeLayout>

我在哪里以及如何放置“我的提取数据”方法，并将其发送到recyclerview？我试图从谷歌搜索并尝试几次。因此以为我在尝试搜索其他方法时会问这里。

Answer 1

可能是封闭线程，但我回答了您的问题。希望我能帮忙

我在哪里以及如何放置“我的提取数据”方法，并将其发送到 recyclerview？

您可能需要制作一个List-ArrayList（或任何获取数据的对象）的对象，以便在其他活动中使用多个RecyclerView。 / p>

就像你到目前为止所做的一样：

List<Course> courseList = Constant.getCoursePass(getActivity());
        CourseListAdapter cAdapter = new CourseListAdapter(getActivity(), courseList);
        recyclerView.setAdapter(cAdapter);

在第一行中，有一个对象List，在此之后，您设置了Adapter，RecyclerView负责显示该列表中的数据。但是，如果您看到constant class，则将其定义为：

private static List<Course> getCourse(Context cCtx)

这意味着，您可能需要摆脱static才能使用多次。因此，第一行是您的答案。您只需要在具有该行的另一个活动上设置另一个RecyclerView的{{1}}。

如何从数据库中获取数据并在多个RecyclerView或Fragments中显示它们？

1 个答案: