Viewbinder Simplecursortreeadapter出现问题-无法将字符串转换为Blob

Question

我在sqlite预先填充的数据库中有图片，我正在使用Simplecursortreeadapter将数据传递到exepndablelistview，但是当打开带有图片的子视图时，应用程序崩溃了，并且在logcat中我得到了“无法将字符串转换为BLLOB”。 在对互联网进行了一些研究之后，我发现（也许）我必须实现我做过的viewbinder（将过去的内容复制并添加到我的专栏中）..我所做的工作基于以下问题的答案：Unable to convert BLOB to String using Loadermanager in android。

但是该应用程序现在无法成功构建...我认为我缺少某些内容或我的代码有问题：

请帮助！谢谢

public class MainActivity extends AppCompatActivity {
    ExpandableListView expandableListView;
    Database mDatabase;

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

        mDatabase = new Database(this);
        mDatabase.open();

        SimpleCursorTreeAdapter.setViewBinder( new MyViewBinder());

        Cursor cursor = mDatabase.getDatabase();
        startManagingCursor(cursor);

        String[] childFrom = new String[]{Database.DATABASE_CHILD_1,Database.DATABASE_CHILD_2};
        String[] groupFrom = new String[]{Database.DATABASE_GROUP_1};

        int[] groupTo = {R.id.group1};
        int[] childTo = {R.id.child1,R.id.child2};

        SimpleCursorTreeAdapter simplecursortreeAdapter = new ExpandableListViewAdapter(
                this,
                cursor,
                R.layout.list_group,
                groupFrom,
                groupTo,
                R.layout.list_child,
                childFrom,
                childTo
        );

        expandableListView = findViewById(R.id.expandableListview);
        expandableListView.setAdapter(simplecursortreeAdapter);
    }

    protected void onDestroy() {
        super.onDestroy();
        mDatabase.close();
    }

    public class MyViewBinder implements ViewBinder {
        @Override
        public boolean setViewValue(View view, Cursor cursor, int columnIndex) {
            int viewID = view.getId();
            switch(viewID){
                case R.id.child1 :
                    TextView friendName = (TextView) view;
                    String friend_name;
                    friend_name = cursor.getString(cursor.getColumnIndex(Database.DATABASE_CHILD_1));
                    friendName.setText(friend_name);
                    break;

                case R.id.child2 :
                    ImageView contactProfile = (ImageView) view;
                    byte[] imageBytes = cursor.getBlob(cursor.getColumnIndex(Database.DATABASE_CHILD_2));
                    if(imageBytes != null ){
                        // Pic image from database
                        contactProfile.setImageBitmap(BitmapFactory.decodeByteArray(imageBytes, 0, imageBytes.length));
                    }else {
                        // If image not found in database , assign a default image
                        contactProfile.setBackgroundResource(R.drawable.disorders);
                    }
                    break;
            }
            return true;
        }

    }

    private class ExpandableListViewAdapter extends SimpleCursorTreeAdapter {
        private ExpandableListViewAdapter(
                Context context,
                Cursor cursor,
                int groupLayout,
                String[] groupFrom,
                int[] groupTo,
                int childLayout,
                String[] childFrom,
                int[] childTo) { super(context, cursor, groupLayout, groupFrom, groupTo, childLayout, childFrom, childTo); }

        protected Cursor getChildrenCursor(Cursor groupCursor) {
            return mDatabase.getID(groupCursor.getInt(groupCursor.getColumnIndex(Database.DATABASE_ID)));
        }

    }


}

Answer 1

我找到了答案（问题是我放错了SimpleCursorTreeAdapter.setViewBinder( new MyViewBinder()); ..

     SimpleCursorTreeAdapter simplecursortreeAdapter = new ExpandableListViewAdapter(
                this,
                cursor,
                R.layout.list_group,
                groupFrom,
                groupTo,
                R.layout.list_child,
                childFrom,
                childTo
        );

        simplecursortreeAdapter.setViewBinder(new MyViewBinder());

        expandableListView = findViewById(R.id.expandableListview);
        expandableListView.setAdapter(simplecursortreeAdapter);
    }

    protected void onDestroy() {
        super.onDestroy();
        mDatabase.close();
    }

    public class MyViewBinder implements ViewBinder {

        @Override
        public boolean setViewValue(View view, Cursor cursor, int columnIndex) {
            int viewID = view.getId();
            switch(viewID){
                case R.id.group1 :
                    TextView groupName = (TextView) view;
                    String groupname;
                    groupname = cursor.getString(cursor.getColumnIndex(Database.DATABASE_GROUP_1));
                    groupName.setText(groupname);
                    break;

                case R.id.child1 :
                    TextView friendName = (TextView) view;
                    String friend_name;
                    friend_name = cursor.getString(cursor.getColumnIndex(Database.DATABASE_CHILD_1));
                    friendName.setText(friend_name);
                    break;

                case R.id.child2 :
                    ImageView contactProfile = (ImageView) view;
                    byte[] imageBytes = cursor.getBlob(cursor.getColumnIndex(Database.DATABASE_CHILD_2));
                    if(imageBytes != null ){
                        // Pic image from database
                        contactProfile.setImageBitmap(BitmapFactory.decodeByteArray(imageBytes, 0, imageBytes.length));
                    }else {
                        // If image not found in database , assign a default image
                        contactProfile.setBackgroundResource(R.drawable.disorders);
                    }
                    break;
            }
            return true;
        }

    }

    private class ExpandableListViewAdapter extends SimpleCursorTreeAdapter {
        private ExpandableListViewAdapter(
                Context context,
                Cursor cursor,
                int groupLayout,
                String[] groupFrom,
                int[] groupTo,
                int childLayout,
                String[] childFrom,
                int[] childTo) { super(context, cursor, groupLayout, groupFrom, groupTo, childLayout, childFrom, childTo); }

        protected Cursor getChildrenCursor(Cursor groupCursor) {
            return mDatabase.getID(groupCursor.getInt(groupCursor.getColumnIndex(Database.DATABASE_ID)));
        }

    }


}