Question

朋友们，我曾尝试在自定义对话框中实现列表视图，并使用JSON动态传递数据并搜索到处但是没有任何解决方案我已经尝试了过去3天的所有内容而且我也没有看到任何错误在我的代码中我也正确设置了适配器我收到此错误

尝试在空对象引用上调用虚方法'void android.widget.ListView.setAdapter（android.widget.ListAdapter）'

public class Cat_comment_adap extends BaseAdapter {

    String cid;
    ImageLoader imageLoader = AppController.getInstance().getImageLoader();
    int idddget;
    private LayoutInflater inflater;
    private List<CurrentList> catlist;
    private PopupWindow commentWindow;
    ArrayList<CurrentList> commentlist = new ArrayList<CurrentList>();

Activity activity;
    public Cat_comment_adap(Activity activity, List<CurrentList> catlist) {
        this.activity = activity;
        this.catlist = catlist;


    }

    @Override
    public int getCount() {
        return catlist.size();
    }

    @Override
    public Object getItem(int i) {
        return catlist.get(i);
    }

    @Override
    public long getItemId(int i) {
        return i;
    }

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {
        inflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        view = inflater.inflate(R.layout.cat_row, viewGroup, false);


        NetworkImageView singleimg = (NetworkImageView) view.findViewById(R.id.singleimg);
        final ImageView agree = (ImageView) view.findViewById(R.id.agree);
        ImageView commentbox = (ImageView) view.findViewById(R.id.commentbox);
        commentbox.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                onShowpopup(view);
                Toast.makeText(activity, "Comments Button clicked", Toast.LENGTH_SHORT).show();
            }
        });

        final CurrentList catertlist = catlist.get(i);

        singleimg.setImageUrl(catertlist.getCatimg(), imageLoader);

        idddget = catertlist.getCcids();
        SharedPreferences eveid = activity.getSharedPreferences("loginPrefs", Context.MODE_PRIVATE);
        cid = eveid.getString("userid", "");

        agree.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String url = "http://sampletemplates.net/majority/api.php?action=addVote&question_id=" + idddget + "&user_id=" + cid + "&vote=1&source=android";
                Log.d("Vote", "http://sampletemplates.net/majority/api.php?action=addVote&question_id=" + idddget + "&user_id=" + cid + "&vote=1&source=android");
                JsonObjectRequest voting = new JsonObjectRequest(Request.Method.POST, url, null, new Response.Listener<JSONObject>() {
                    @Override
                    public void onResponse(JSONObject response) {
                        try {
                            String votings = response.getString("status");
                            if (votings.equals("success")) {
                                agree.setImageResource(R.drawable.agreed);
                                Toast.makeText(activity, "Voted Successfully", Toast.LENGTH_SHORT).show();
                            } else {
                                Toast.makeText(activity, "Already Voted", Toast.LENGTH_SHORT).show();
                            }
                        } catch (JSONException e) {
                            e.printStackTrace();
                        }

                    }
                }, new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {

                    }
                });
                AppController.getInstance().addToRequestQueue(voting);
            }
        });
        return view;
    }

    public void onShowpopup(View v) {
        LayoutInflater layoutInflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View popupview = layoutInflater.inflate(R.layout.current_comment_dialog, null);
        ListView commentsListView = (ListView) v.findViewById(R.id.commentsListView);
//        commentAdapter = new comment_adapter(activity, commentlist);
        WindowManager wm = (WindowManager) activity.getSystemService(Context.WINDOW_SERVICE);
        Display display = wm.getDefaultDisplay();
        Point size = new Point();
        display.getSize(size);
        int width = size.x;
        int height = size.y;
        commentWindow = new PopupWindow(popupview, width - 50, height - 400, true);
        commentWindow.setBackgroundDrawable(activity.getResources().getDrawable(R.drawable.comment_bg));
        commentWindow.setFocusable(true);
        commentWindow.setOutsideTouchable(true);
        commentWindow.showAtLocation(v, Gravity.BOTTOM, 0, 100);
        commentsListView.setAdapter(new comment_adapter(activity,commentlist));
        commentAdapter.notifyDataSetChanged();
    }

适配器类

public class comment_adapter extends BaseAdapter {
    private Activity activity;
    private LayoutInflater inflater;
    private List<CurrentList> commentlist;
    public comment_adapter(Activity activity, List<CurrentList> commentlist){
        this.activity = activity;
        this.commentlist = commentlist;

    }

    @Override
    public int getCount() {
        return commentlist.size();
    }

    @Override
    public Object getItem(int i) {
        return commentlist.get(i);
    }

    @Override
    public long getItemId(int i) {
        return i;
    }

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {
        if (inflater == null)
            inflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        if (view == null)
            view = inflater.inflate(R.layout.comment_row, viewGroup, false);
        TextView user_name = (TextView) view.findViewById(R.id.user_name);
        TextView posttime = (TextView) view.findViewById(R.id.posttime);
        TextView comtsdetails = (TextView) view.findViewById(R.id.comtsdetails);
        CurrentList listofcomments = commentlist.get(i);
        user_name.setText(listofcomments.getEvtusername());
        posttime.setText(listofcomments.getTimetaken());
        comtsdetails.setText(listofcomments.getEvcomment());
        return view;
    }
}

Answer 1

        public void onClick(View view) {
            onShowpopup(view);
            Toast.makeText(activity, "Comments Button clicked", Toast.LENGTH_SHORT).show();
        }

此处传递的视图不是您想象的R.layout.cat_row，但它是一个点击的按钮。

所以只需使用onShowpopup(self.view)就行了:)

或更改为onClick(View clickedButton)

Answer 2

这个类中的cat_comment_adap在方法onShowpopup中发生了变化 查看popupview = layoutInflater.inflate（R.layout.current_comment_dialog，null）; ListView commentsListView =（ListView）v.findViewById（R.id.commentsListView）;

到

查看popupview = layoutInflater.inflate（R.layout.current_comment_dialog，null）; ListView commentsListView =（ListView）popupview.findViewById（R.id.commentsListView）;

因为你从这个布局中膨胀listview所以你必须给出膨胀布局对象的名称而不是方法的参数

list view adapter在自定义对话框上设置null对象

2 个答案: