Android ListView 未立即使用 notify DataSetChanged 刷新

Question

我正在构建一个UI，在其中使用ListView来保存有关用户提出的问题的数据。每当用户创建新问题时，我都会尝试更新列表视图。现在的问题是数据已更新，但不是立即更新。添加问题后，我需要导航到另一个屏幕，然后返回查看更新的列表。这也导致了我想解决的其他一些问题（布局无法正确显示）这是我的活动的代码：

public class QuestionsScreen extends Activity {
.....
.....
.....
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_questions_screen);
        .....
        questions=new ArrayList<String>();
        qId=new ArrayList<Integer>();
        .....
        .....
        //building API
        resourceApi = ApiBuilder.getResourceApi(token);
        // calling API function to get questions from db
        resourceApi.listQuestions(groupId, new Callback<List<Question>>(){
            @Override
            public void failure(RetrofitError arg0) {
                // TODO Auto-generated method stub
            }
            @Override
            public void success(List<Question> arg0, Response arg1) {
                // TODO Auto-generated method stub
                for(Question q:arg0)
                {
                    questions.add(q.getTitle());
                    qId.add(q.getId());
                }
            }
        });

        adapter= new ArrayAdapter<String>this,android.R.layout.simple_list_item_1,questions);
        lv.setAdapter(adapter);
        .....
        AlertDialog.Builder dialog = new AlertDialog.Builder(this);
        LayoutInflater inflater = getLayoutInflater();
        final View x;
        x = inflater.inflate(R.layout.groupdialog, null);
        dialog.setView(x);
        dialog.setTitle("Add question");
        TextView t= (TextView)x.findViewById(R.id.dialogTv);
        t.setText("Please type in the question");
        dialog.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface d, int which) {
                // TODO Auto-generated method stub
                name = (EditText) x.findViewById(R.id.dialog_groupName);
                out = name.getText().toString();
                addQuestion();
                d.dismiss();
            }
        });
        dialog.setNegativeButton("Cancel",
                new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface d, int which) {
                        // TODO Auto-generated method stub
                        d.cancel();
                    }
                });
        alert = dialog.create();
        //button to ask a new question
        newQ.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                alert.show();
            }
        });
    }

这是按下"添加新问题"按钮时调用的函数：

public void addQuestion()
    {
        resourceApi.createQuestion(groupId, out, new Callback<Question>(){
            @Override
            public void failure(RetrofitError err) {
                // TODO Auto-generated method stub
            }
            @Override
            public void success(Question q, Response response) {
                // TODO Auto-generated method stub
//              adapter.add(q.getTitle());
                questions.add(q.getTitle());
                qId.add(q.getId());
            }
        });
        adapter.notifyDataSetChanged();
        Toast.makeText(QuestionsScreen.this, "New Question created",Toast.LENGTH_LONG).show();
    }

将显示吐司。但是，列表视图不会使用新问题进行更新。我也尝试使用adapter.add（），但它只是引起了一些其他问题，所以我不想使用它。谁能提出更好的方法或指出我做错了什么？

Answer 1

你必须在回调中通知你数据（成功函数）

尝试这样的事情：

resourceApi.createQuestion(groupId, out, new Callback<Question>(){
        @Override
        public void failure(RetrofitError err) {
            // TODO Auto-generated method stub
        }
        @Override
        public void success(Question q, Response response) {
            // TODO Auto-generated method stub
            adapter.add(q.getTitle());
            questions.add(q.getTitle());
            qId.add(q.getId());
//Notify once you have add something in questions
            adapter.notifyDataSetChanged();
        }
});