viewbinder Simplecursortreeadapter 出现问题 - 无法将字符串转换为 blob

Question

我的 sqlite 预填充数据库中有图片，我正在使用 Simplecursortreeadapter 将数据传递给 exepndablelistview ，但是当打开带有图片的子视图并且在 logcat 中我得到“无法将字符串转换为 BLLOB”时，应用程序崩溃了。 在对互联网进行了一些研究之后，我发现（也许）我必须实现我所做的 viewbinder（复制过去并添加到我的专栏中）..我所做的是基于这个问题的答案：Unable to convert BLOB to String using Loadermanager in android..

但是应用程序现在无法成功构建...我想我遗漏了一些东西或者我的代码有问题：

请帮忙！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)));
        }

    }


}