在 android 的 imageview 上加载图像时，在 Picasso 库上放置 URL 时出错

Question

我在从服务器加载图像并使用 Picasso 库显示它时出错，我有一个 JSON 字符串，它有一个 "img" => "whateverimageofanarticle.jpg" 字段，其中在 JSON 字符串上该列的值可能会根据数据库的内容而有所不同。我可以获取 JSON 字符串给出的图像路径，并将其显示在文本视图上，但是当我将它放在毕加索库中 .load() 方法的参数上时，它不起作用并停止了我的应用程序的执行:(

无论如何，我使用片段而不是库来更轻松和更快地执行应用程序（我不知道片段是否对我的问题很重要），代码也在 asynctask 的 postExecute 方法中，其中在onPostExecute() 中被覆盖。这是我的确切代码和我的整个代码。

ImageView banner = new ImageView(getActivity().getApplicationContext());
banner.getLayoutParams().height = 50;
banner.getLayoutParams().width = 80;
banner.requestLayout();

Picasso.with(getActivity().getApplicationContext())
    .load("http://rtu-astronet.com/emag/"+_jsonObject.optString("img").toString())
    .into(banner);

完整代码：

public class CollegeBulletinListFragment extends Fragment implements OnClickListener, Connector.OnPostExecuteListener{
    public CollegeBulletinListFragment(){
    }

    TextView kem;
    TextView headlinehead;
    TextView shortdesc;
    TextView headlinesender;
    LinearLayout llist;
    ImageButton img;
    ProgressBar pbColBul;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_collegebulletinlist, container, false);
        kem = (TextView) rootView.findViewById(R.id.mon_title);
        img = (ImageButton) rootView.findViewById(R.id.imageButton1);
        pbColBul = (ProgressBar) rootView.findViewById(R.id.pBcollegebul);
        img.setOnClickListener(this);
        headlinehead = (TextView) rootView.findViewById(R.id.mon_head_title);
        shortdesc = (TextView) rootView.findViewById(R.id.mon_head_desc);
        headlinesender = (TextView) rootView.findViewById(R.id.mon_head_sender);
        String c = getArguments().getString("passingWord");
        llist = (LinearLayout) rootView.findViewById(R.id.lllist);
        int colval = this.setTextAndColorsToHead(c);
        pbColBul.setVisibility(ProgressBar.VISIBLE);
        //Execute items on scroll view
        String secondFlag = "list";
        Connector connect= new Connector(getActivity().getApplicationContext(),colval,secondFlag,0,0,0,"","");
        connect.setOnPostExecuteListener(this);
        connect.execute("");
        return rootView;
    }

    public int setTextAndColorsToHead(String arg){
        int collegeval = 0;
        if (arg.equals("GN")){
            kem.setText("General News");
        } else if (arg.equals("CCS")){
            kem.setText("College of Computer Studies");
            collegeval = 1;
        } else if (arg.equals("COE")){
            kem.setText("College of Engineering");
            collegeval = 2;
        } else if (arg.equals("COED")){
            kem.setText("College of Education");
            collegeval = 4;
        } else if (arg.equals("CON")){
            kem.setText("College of Nursing");
            collegeval = 3;
        } else if (arg.equals("CBA")){
            kem.setText("College of Business and Accountancy");
            collegeval = 5;
        } else if (arg.equals("CAS")){
            kem.setText("College of Arts and Sciences");
            collegeval = 6;
        } else if (arg.equals("CIHM")){
            kem.setText("College of International and Hospitality Management");
            collegeval = 7;
        } 
        return collegeval;
    }

    @Override
    public void onClick(View arg0) {
        // TODO Auto-generated method stub

        SpecificArticleFragment spcf = new SpecificArticleFragment();
        Bundle args = new Bundle();
        String tag = arg0.getTag().toString();
        args.putString("art_id",tag);
        spcf.setArguments(args);
        FragmentManager fm = getFragmentManager();
        fm.beginTransaction().replace(R.id.content_frame, spcf).commit();
    }

    @Override
    public void onPostExecute(String result) {
        //headlinehead.setText(result);
        try{
            JSONObject jsonRootObj = new JSONObject(result);
            JSONArray jsonArray = jsonRootObj.optJSONArray("Data");
            JSONObject jsonObject = jsonArray.getJSONObject(0);
            //code for headline
            this.headlinehead.setText(jsonObject.optString("title").toString());
            this.shortdesc.setText(jsonObject.optString("shortdesc").toString());
            this.headlinesender.setText(jsonObject.optString("penname").toString());
            this.img.setTag(jsonObject.optString("id").toString());
            //code for headline
            for (int p = 1; p < jsonArray.length(); p++){
                JSONObject _jsonObject = jsonArray.getJSONObject(p);
                LinearLayout conteach = new LinearLayout(getActivity().getApplicationContext());
                LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
                conteach.setLayoutParams(lp);
                conteach.setOrientation(LinearLayout.VERTICAL);

                ImageView banner = new ImageView(getActivity().getApplicationContext());
                banner.getLayoutParams().height = 50;
                banner.getLayoutParams().width = 80;
                banner.requestLayout();

                Picasso.with(getActivity().getApplicationContext())
                .load("http://rtu-astronet.com/emag/"+_jsonObject.optString("img").toString())
                .into(banner);


                TextView art_title = new TextView(getActivity().getApplicationContext());
                art_title.setText(_jsonObject.optString("title").toString());
                art_title.setTextSize(20);
                art_title.setLayoutParams(new LayoutParams(350,LayoutParams.WRAP_CONTENT));

                TextView art_shortdesc = new TextView(getActivity().getApplicationContext());
                art_shortdesc.setText(_jsonObject.optString("shortdesc").toString());
                art_shortdesc.setTextSize(14);
                art_shortdesc.setTypeface(null, Typeface.ITALIC);
                art_shortdesc.setLayoutParams(new LayoutParams(350,LayoutParams.WRAP_CONTENT));

                TextView art_sender = new TextView(getActivity().getApplicationContext());
                art_sender.setText("Written by: " + _jsonObject.optString("sender").toString());
                art_sender.setTextSize(14);
                art_sender.setLayoutParams(new LayoutParams(350,LayoutParams.WRAP_CONTENT));
                art_sender.setPadding(0, 0, 0, 15);


                conteach.addView(art_title);
                conteach.addView(art_shortdesc);
                conteach.addView(art_sender);
                conteach.setTag(_jsonObject.optString("id").toString());
                conteach.setClickable(true);
                conteach.setOnClickListener(new OnClickListener() {
                    public void onClick(View v) {
                        SpecificArticleFragment spcf = new SpecificArticleFragment();
                        Bundle args = new Bundle();
                        args.putString("art_id", v.getTag().toString());
                        spcf.setArguments(args);

                        FragmentManager ft = getFragmentManager();
                        ft.beginTransaction().replace(R.id.content_frame, spcf).commit();
                    }
                 });                
                this.llist.addView(conteach);

            }
            this.pbColBul.setVisibility(ProgressBar.GONE);
        } catch(JSONException e){

        }
    }
}

Answer 1

问题解决了，我只是改变

banner.getLayoutParams().height = 50;
banner.getLayoutParams().width = 80;
banner.requestLayout(); 

到 banner.setLayoutParams() 并设置布局宽度和高度，我还为 imageview 插入了一个初始图像，该图像将在 doInBackground() 方法之后发生变化