Binding listview row with sqlite database for custom rows

问题

I have a listview which loads its data from sqlite database. Each row in listview has image , textview and a checkbox. The sqlitedatabase rows has image and text data + some other columns.

My question is can I bind my listview with the database so that all rows will be loaded with required data automatically. (image + textview) There are examples to bind a simple list of textviews. What about complex rows ? Also there are few spinners which can filter the data in list depending on its value. (Which act as a WHERE clause on my DB)

Currently I am managing this all by generating the view for my custom adapter for each row. So each time I query database and populate data. I hold the last listview results , make a newer results based on actions/conditions like spinner values, then notifydatachanged to adapter to load my new results.

To add features like DELETE , ADD , SEARCH -- I have to manage it all using collections.

Is there any simple way of doing this ? As if the db is large then the approach of holding such huge set of results in memory is not good. And is painful for managing it. Thanks.

回答1:

Here is my example for row, constructed from two records from db + image (at current - one image for any row, but it can be improved for specific image from db):

    public class DomainAdapter extends SimpleCursorAdapter{
    private Cursor dataCursor;

    private LayoutInflater mInflater;
    ....

    public DomainAdapter(Context context, int layout, Cursor dataCursor, String[] from,
            int[] to) {
        super(context, layout, dataCursor, from, to);
            this.dataCursor = dataCursor;
            mInflater = LayoutInflater.from(context);
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        // A ViewHolder keeps references to children views to avoid unneccessary calls
        // to findViewById() on each row.
        ViewHolder holder;

        // When convertView is not null, we can reuse it directly, there is no need
        // to reinflate it. We only inflate a new View when the convertView supplied
        // by ListView is null.
        if (convertView == null) {
            convertView = mInflater.inflate(layout, null);

            // Creates a ViewHolder and store references to the two children views
            // we want to bind data to.
            holder = new ViewHolder();
            holder.text1 = (TextView) convertView.findViewById(R.id.test_track);
            holder.text2 = (TextView) convertView.findViewById(R.id.test_band);
            holder.icon = (ImageView) convertView.findViewById(R.id.test_artwork);

            convertView.setTag(holder);
        } else {
            // Get the ViewHolder back to get fast access to the TextView
            // and the ImageView.
            holder = (ViewHolder) convertView.getTag();
        }

        // Bind the data efficiently with the holder.
        // Cursor to current item
        dataCursor.moveToPosition(position);
        int title_index = dataCursor.getColumnIndex(fields[0]); 
        String title = dataCursor.getString(title_index);

        int description_index = dataCursor.getColumnIndex(fields[1]); 
        String description = dataCursor.getString(description_index);

        holder.text1.setText(title);
        holder.text2.setText(description);
        holder.icon.setImageResource(R.drawable.alert_dialog_icon);

        return convertView;
    }

    static class ViewHolder {
        TextView text1;
        TextView text2;
        ImageView icon;
    }
}

and using this adapter:

databaseListAdapter = new DomainAdapter(this, 
                R.layout.test_layout, 
                databaseCursor, 
                new String[] {"title", "description"}, 
                new int[] { R.id.test_track, R.id.test_track });
databaseListAdapter.notifyDataSetChanged();
DomainView.setAdapter(databaseListAdapter);

and layout:

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="64dip"
    android:padding="6dip">

    <TextView
        android:id="@+id/test_band"  
        android:layout_width="fill_parent" 
        android:layout_height="26dip" 

        android:layout_below="@+id/test_track"
        android:layout_alignLeft="@id/test_track"
        android:layout_alignParentBottom="true"

        android:gravity="top" />

    <TextView
        android:id="@id/test_track"  
        android:layout_marginLeft="6dip"
        android:layout_width="fill_parent"
        android:layout_height="26dip"

        android:layout_toRightOf="@+id/test_artwork"

        android:textAppearance="?android:attr/textAppearanceMedium"
        android:gravity="bottom" />

    <ImageView
        android:id="@id/test_artwork"
        android:layout_width="56dip"
        android:layout_height="56dip"
        android:layout_gravity="center_vertical" />

</RelativeLayout>

回答2:

My question is can I bind my listview with the database so that all rows will be loaded with required data automatically. (image + textview) There are examples to bind a simple list of textviews. What about complex rows ?

Yes, you can do a Cursor to complex view mapping by implementing your own CursorAdapter and overriding the bindView().

来源：https://stackoverflow.com/questions/4520524/binding-listview-row-with-sqlite-database-for-custom-rows

标签

android

database

listview

binding