Update viewpager dynamically

Question

I have a ViewPager. Data is stored in the database. I want update it dynamically. It is necessary that the element disappears immediately, but it does not work. Data is updated after i called method onCreate. I try all advice, but it does not help. What i did wrong? Help me find a solution, please.

TextPagerAdapter.java

public class TextPagerAdapter extends FragmentStatePagerAdapter {

List<String> data;

public TextPagerAdapter(FragmentManager fm, List<String> data) {
    super(fm);
    this.data = data;

}

@Override
public Fragment getItem(int i) {

    Fragment fragment = new ItemFragment();

    Bundle args = new Bundle();
    args.putString(ItemFragment.ARG_TEXT, data.get(i));
    args.putInt(ItemFragment.ARG_POSITION, i+1);
    args.putInt(ItemFragment.ARG_COUNT, getCount());

    fragment.setArguments(args);

    return fragment;

}

@Override
public int getCount() {

    return data.size();
}

public String getTextVP(int i) {
    return data.get(i);
}

@Override
public CharSequence getPageTitle(int position) {
    return "Item " + (position + 1);
}


@Override
public int getItemPosition(Object object) {
    return POSITION_NONE;
}
}

ItemFragment.java

public class ItemFragment extends Fragment {

public static final String ARG_TEXT = "item_text";
public static final String ARG_POSITION = "item_position";
public static final String ARG_COUNT = "item_count";
TextView text1, textCount;

@Override
public View onCreateView(LayoutInflater inflater,
                         ViewGroup container, Bundle savedInstanceState) {

    View rootView = inflater.inflate(
            R.layout.fragment, container, false);

    Bundle args = getArguments();

    text1 = (TextView) rootView.findViewById(R.id.text1);
    text1.setText(args.getString(ARG_TEXT));

    textCount = (TextView) rootView.findViewById(R.id.txtCount);
    textCount.setText(args.getInt(ARG_POSITION) + " / " + args.getInt(ARG_COUNT));

    return rootView;
}
}

StartAppScreen.java

public class StartAppScreen extends AppCompatActivity implements View.OnClickListener {

private DatabaseHelper mDBHelper;
private SQLiteDatabase mDb;
ViewPager mViewPager;
TextPagerAdapter mTextPagerAdapter;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.patters_layout);

    List<String> data = new ArrayList<>();
    mDBHelper = new DatabaseHelper(this);

    init();

    Intent intent = getIntent();
    String condition = intent.getStringExtra("condition");
    String column = intent.getStringExtra("column");
    Boolean allWords = intent.getBooleanExtra("allWords", false);

    data.addAll(getDataFromTable(mDb, column, condition, allWords));

    if (allWords) Collections.shuffle(data);

    mTextPagerAdapter = new TextPagerAdapter(
            getSupportFragmentManager(), data);

    mViewPager.setAdapter(mTextPagerAdapter);
}

@Override
public void onClick(View v) {

    switch (v.getId()) {

        case R.id.btnDel:
            String s = mTextPagerAdapter.getTextVP(mViewPager.getCurrentItem());
            /*Delete data from db*/
            mDb.delete(TABLE_NAME, WORD_ROW_NAME + "= ?", new String[] {s} );
            /*It is not work*/
            mTextPagerAdapter.notifyDataSetChanged();
            break;
    }
}


private void init() {

    try {
        mDBHelper.updateDataBase();
    } catch (IOException mIOException) {
        throw new Error("UnableToUpdateDatabase");
    }

    try {
        mDb = mDBHelper.getWritableDatabase();
    } catch (SQLException mSQLException) {
        throw mSQLException;
    }

    Button btnAdd = (Button) findViewById(R.id.btnAdd);
    btnAdd.setOnClickListener(this);
    Button btnDel = (Button) findViewById(R.id.btnDel);
    btnDel.setOnClickListener(this);
    mViewPager = (ViewPager) findViewById(R.id.pager);
}
}

Possible duplicate of [Update ViewPager dynamically?](https://stackoverflow.com/questions/10849552/update-viewpager-dynamically) — Vishal Yadav, Sep 25 '17 at 13:47

score 0 · Accepted Answer · answered Sep 25 '17 at 13:56

0

Actually, you don't update list of string in your TextPagerAdapter. You update only in DB. Fetch data again and change the value of the data field in mTextPagerAdapter.

answered Sep 25 '17 at 13:56

Mike

2,547
3
16
30

Thanks, it works. Before mTextPagerAdapter.notifyDataSetChanged(); I wrote data.remove(mViewPager.getCurrentItem()); – Сергей Sep 25 '17 at 15:16

Update viewpager dynamically

1 Answers1