需要帮助将firebase中的数据转换为string []数组。尝试了所有可用的方法，但坚持只获取最后一个值

Posted 2021-04-03

我试图将存储在firebase中的所有值分成两个单独的string []数组。我正在获取值，但在将其显示到列表视图中时，它仅显示最后添加的值。我也在使用自定义适配器类。

Database.child("users").child(mUserId).child("locs").addValueEventListener(new ValueEventListener() {
    @Override
    public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

        for (DataSnapshot ds : dataSnapshot.getChildren()) {

            final String[] main = {(String) ds.child("title").getValue()};
            final String[] sub = {(String) ds.child("addr").getValue()};
            System.out.println(main);//here i am getting 5 outputs like  [Ljava.lang.String;@88b5c49. i have 5 values in firebase too

            CustomAdapter adapter2 = new CustomAdapter(Location.this, main, sub);
            list.setAdapter(adapter2);
        }
    }
});

自定义适配器类

public class CustomAdapter extends ArrayAdapter<String>{

    private final Activity context;
    private final String[] main;
    private final String[] sub;
    public CustomAdapter(Activity context,
                         String[] main, String[] sub) {
        super(context, R.layout.layout, main);
        this.context = context;
        this.main = main;
        this.sub = sub;

    }
    @Override
    public View getView(int position, View view, ViewGroup parent) {
        LayoutInflater inflater = context.getLayoutInflater();
        View rowView= inflater.inflate(R.layout.layout, null, true);
        TextView txtTitle = (TextView) rowView.findViewById(R.id.title);
        TextView txtSub=rowView.findViewById(R.id.subtitle);
        txtTitle.setText(main[position]);
        txtSub.setText(sub[position]);
        return rowView;
    }
}

答案

尝试在循环之外移动String[] main，String[] sub。然后尝试将所有值添加到循环内的这些数组中。然后在完成循环后调用这些

CustomAdapter adapter2 = new CustomAdapter(Location.this, main, sub);
list.setAdapter(adapter2);

整个代码应该是这样的。

final String[] main; // declare it with the size it needs.
final String[] sub;  // declare it with the size it needs.              
for(DataSnapshot ds:dataSnapshot.getChildren()) {
   // sum your result to main and sub
}
CustomAdapter adapter2 = new CustomAdapter(Location.this, main, sub);
list.setAdapter(adapter2);