Question

我有ListView Activity，它显示来自Sqlite的已保存记录列表。通过按下每个索引，它会导航到下一个Activity，该Activity根据已按下的ListView索引显示值。

一切都按预期工作，但每当我按下第二个活动中的删除按钮时，它会导航回ListView活动，但它不会更新ListView。所以我必须再次向后退一个Activity并重新打开它，以便它最终开始更新ListView。

这是我的ListView活动代码：

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

    artistList = (ListView) findViewById(R.id.artistList);
    databasehandler = new SqliteHandler(ViewArtistActivity.this);
    allArtists = databasehandler.getAllArtists();
    artistName = new ArrayList<>();

    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);

    if (allArtists.size() > 0) {
        for (int i=0; i < allArtists.size(); i++) {
            ArtistModel artistModel = allArtists.get(i);
            artistName.add(artistModel.getArtistName());
        }
    }

    adapter = new ArrayAdapter(ViewArtistActivity.this, android.R.layout.simple_list_item_1, artistName);
    artistList.setAdapter(adapter);

    artistList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

            singleArtistDetails = new ArrayList<>();

            ArtistModel artistModel = allArtists.get(position);
            singleArtistDetails.add(artistModel.getArtistName());
            singleArtistDetails.add(artistModel.getArtistDOB());
            singleArtistDetails.add(artistModel.getArtistBiography());

            Intent intent = new Intent(ViewArtistActivity.this, SavedArtistDetailsActivity.class);
            intent.putExtra("NAME", singleArtistDetails.get(0));
            intent.putExtra("DOB", singleArtistDetails.get(1));
            intent.putExtra("BIOGRAPHY", singleArtistDetails.get(2));
            startActivity(intent);
        }
    });
}

Answer 1

您需要覆盖onResume中的ListViewActivity功能。重新填充artistName阵列，然后在适配器上调用notifyDataSetChanged。

@Override
protected void onResume() {
    super.onResume();
    allArtists = databasehandler.getAllArtists();

    // Clear the list
    artistName.clear();

    if (allArtists.size() > 0) {
        for (int i = 0; i < allArtists.size(); i++) {
            ArtistModel artistModel = allArtists.get(i);
            artistName.add(artistModel.getArtistName());
        }
    }

    adapter.notifyDataSetChanged();
}

要详细了解活动生命周期，请参阅documentation here。

删除第二个活动中的记录后，ListView未更新

1 个答案: