如何将 SQLite 数据加载到 viewpager 中？

Question

我是 android 编程新手，我需要将 SQLite 数据库中的每一行加载到 viewpager（我的 SQLite 数据库包含字段“ID、NAME、AGE、ADDRESS”），以便能够导航到每个通过向左和向右滑动来排列。我未能找到正确的解决方案。我已经尝试解决这个问题一个星期了。

如果有人能帮助我解决这个问题，那将是一件幸事。非常感谢！

Answer 1

经过大量研究和尝试，我想出了一个可行的解决方案。下面的代码都在 MainActivity 中列出。很直接。我希望这可以帮助其他人。如果您有任何问题，请发表评论。

public class MainActivity extends AppCompatActivity {

float x1,x2;
float y1, y2;

int currentPage;
ViewPager mViewPager;
String ID;
List<String> listID = new ArrayList<String>();
List<String> listName = new ArrayList<String>();
List<String> listMtrno = new ArrayList<String>();
String SearchString = null;
CursorPagerAdapter mAdapter;
Cursor cursor;
DatabaseHelper databaseHelper;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    Bundle extras = getIntent().getExtras();

    getSupportActionBar().setDisplayShowHomeEnabled(true);

    databaseHelper = new DatabaseHelper(this);

    setContentView(R.layout.pager);

    databaseHelper = new DatabaseHelper(MainActivity.this);
    cursor = databaseHelper.fetch();
    mAdapter = new CursorPagerAdapter(this, cursor);

    mViewPager = (ViewPager) findViewById(R.id.pager);
    mViewPager.setAdapter(mAdapter);

    mViewPager.setPageTransformer(true, new ZoomOutPageTransformer());

    if (extras != null)
    {
        SearchString = extras.getString("SearchFlag");
        if (SearchString != null) {
            mViewPager.setCurrentItem(Integer.parseInt(SearchString) - 1);

        } else {
            if (cursor.moveToFirst()){
                while(!cursor.isAfterLast()){
                    cursor.moveToNext();
                }
            }
        }
        Log.d("MainActivity", "Search(A): " + SearchString);
    }
}

private class CursorPagerAdapter extends PagerAdapter {

    private Cursor cursor;
    private LayoutInflater inflater;

    public CursorPagerAdapter(Context context, Cursor cursor) {

        Log.d("Main Activity", "MyCursorPagerAdapter.onCreate()");

        this.cursor = cursor;
        this.inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }
    public void swapCursor(Cursor cursor) {
        //if(cursor != null) {

        Log.d("Main Activity", "swapCursor().");

        this.cursor = cursor;
        //notifyDataSetChanged();
        //}
    }
    @Override
    public int getCount() {
        if(cursor == null) {
            return 0;
        } else {
            return cursor.getCount();
        }
    }
    @Override
    public void destroyItem(ViewGroup view, int position, Object object) {

        cursor.moveToPosition(position);
        (view).removeView((LinearLayout) object);
    }
    @Override
    public Object instantiateItem(ViewGroup view, int position) {

        position = position % cursor.getCount();

        cursor.moveToPosition(position);

        LinearLayout layout = (LinearLayout) inflater.inflate(R.layout.fragment_listener, null);

        TextView f1_recno = layout.findViewById(R.id.TV_recno);
        TextView f1_acctno = layout.findViewById(R.id.TV_acctno);
        TextView f1_route = layout.findViewById(R.id.TV_route);
        TextView fl_name = layout.findViewById(R.id.TV_name);
        TextView fl_mtrno = layout.findViewById(R.id.TV_mtrno);

        f1_recno.setText((cursor.getPosition() + 1) + " of " + cursor.getCount() + " records");
        f1_acctno.setText(cursor.getString(cursor.getColumnIndex("ACCTNO")));
        f1_route.setText(cursor.getString(cursor.getColumnIndex("ROUTE")));
        fl_name.setText(cursor.getString(cursor.getColumnIndex("NAME")));
        fl_mtrno.setText(cursor.getString(cursor.getColumnIndex("MTRNO")));

            (view).addView(layout);
        return layout;
    }
    @Override
    public boolean isViewFromObject(View view, Object object) {
        return view == object;
    }
}

我将一个表从数据库加载到一个游标对象，并将它连接到我的 CursorPagerAdapter。每行数据的加载在 InstantiateItem 对象中完成。