Java Android Studio解析文本视图

我有一个问题，我不知道如何通过setter和getter将json解析放在textView上。 我知道如何将我的json放在listView上，我会显示他，但不会在TextView上显示我的代码

这个类代表我的布局列表视图，但我放了一个文本视图进行测试

public class AfficheurListView extends AppCompatActivity {
String json_string;
JSONObject jObj = null;
ValeursAdapter valeursAdapter;
TextView textView;
Valeurs valeurss;
ListView listView;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.display_listview_layout);
    json_string=getIntent().getExtras().getString("json_data");

    listView =(ListView)findViewById(R.id.listview);
    textView=(TextView)findViewById(R.id.textView4);

    valeursAdapter=new ValeursAdapter(this,R.layout.new_layout);

    listView.setAdapter(valeursAdapter);
    textView.setText(valeurss.getMpx());

    try {
      /*
            Tab json   []
      jsonObject=new JSONObject(json_string);
       jsonArray=jsonObject.getJSONArray("server_reponse");
       int count=0 ;*/

        // Json Object {}
        String mpx,rds,al,ar,frequence,pilots,id,id_SIGFOX,timestamps,rf;
        jObj = new JSONObject(json_string);
        mpx=  jObj.getString("MPX");
        rds =jObj.getString("RDS");
        rf=jObj.getString("RF");
        frequence =jObj.getString("Frequence");
        timestamps=jObj.getString("timestamp");
        id= jObj.getString("id");
        id_SIGFOX= jObj.getString("id_SIGFOX");
        pilots= jObj.getString("PILOT");
        al= jObj.getString("a_l");
        ar= jObj.getString("a_r");

        Valeurs valeurs=new Valeurs(mpx,rds,al,ar,frequence,pilots,id,timestamps,id_SIGFOX,rf);
        valeursAdapter.add(valeurs);
        //textView.setText(valeurss.getMpx());


    } catch (JSONException e) {

        e.printStackTrace();}

}
}

此类是我的变量的getter和setter：

public class Valeurs{


    private String mpx,rds,al,ar,pilots,frequence,id,timestamps,id_SIGFOX,rf;
        public Valeurs(String mpx, String rds, String al, String ar, String pilots, String frequence, String id, String timestamps, String id_SIGFOX, String rf)

        {
            this.setMpx(mpx);
            this.setRds(rds);
            this.setAl(al);
            this.setAr(ar);
            this.setPilots(pilots);
            this.setFrequence(frequence);
            this.setId(id);
            this.setTimestamps(timestamps);
            this.setId_SIGFOX(id_SIGFOX);
            this.setRf(rf);


        }


    public String getMpx() {
        return mpx;
    }

    public void setMpx(String mpx) {
        this.mpx = mpx;
    }

    public String getRds() {
        return rds;
    }

    public void setRds(String rds) {
        this.rds = rds;
    }

    public String getAl() {
        return al;
    }

    public void setAl(String al) {
        this.al = al;
    }

    public String getAr() {
        return ar;
    }

    public void setAr(String ar) {
        this.ar = ar;
    }

    public String getPilots() {
        return pilots;
    }

    public void setPilots(String pilots) {
        this.pilots = pilots;
    }

    public String getFrequence() {
        return frequence;
    }

    public void setFrequence(String frequence) {
        this.frequence = frequence;
    }

    public String getTimestamps() {
        return timestamps;
    }

    public void setTimestamps(String timestamps) {
        this.timestamps = timestamps;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getId_SIGFOX() {
        return id_SIGFOX;
    }

    public void setId_SIGFOX(String id_SIGFOX) {
        this.id_SIGFOX = id_SIGFOX;
    }

    public String getRf() {
        return rf;
    }

    public void setRf(String rf) {
        this.rf = rf;
    }
}

此类将我的变量放在我的lisView的新布局上：

public class ValeursAdapter  extends ArrayAdapter{

    List list=new ArrayList<>();
    public ValeursAdapter(Context context, int resource) {
        super(context, resource);
    }


    public void add(Valeurs object) {
        super.add(object);
        list.add(object);


    }

    @Override
    public int getCount() {

        return list.size();

    }

    @Nullable
    @Override
    public Object getItem(int position) {
        return list.get(position);

    }

    @NonNull
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
         View row;
        row=convertView;

        ValeursDefini valeursDefini;
        if(row==null)
        {
            LayoutInflater layoutInflater=(LayoutInflater)this.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            row=layoutInflater.inflate(R.layout.new_layout,parent,false);
            valeursDefini=new ValeursDefini();
            valeursDefini.tx_mpx=(TextView)row.findViewById(R.id.tx_mpx);
            valeursDefini.tx_al=(TextView)row.findViewById(R.id.tx_al);
            valeursDefini.tx_ar=(TextView)row.findViewById(R.id.tx_ar);
            valeursDefini.tx_rds=(TextView)row.findViewById(R.id.tx_rds);
            valeursDefini.tx_frequence=(TextView)row.findViewById(R.id.tx_frequence);
            valeursDefini.tx_pilots=(TextView)row.findViewById(R.id.tx_pilots);

            row.setTag(valeursDefini);

        }
            else {
        valeursDefini=(ValeursDefini)row.getTag();
        }
        Valeurs valeurs= (Valeurs) this.getItem(position);
        valeursDefini.tx_mpx.setText(valeurs.getMpx()+"--");
        valeursDefini.tx_rds.setText(valeurs.getRds()+"--");
        valeursDefini.tx_al.setText(valeurs.getAl()+"--");
        valeursDefini.tx_ar.setText(valeurs.getAr()+"--");
        valeursDefini.tx_pilots.setText(valeurs.getPilots()+"--");
        valeursDefini.tx_frequence.setText(valeurs.getFrequence()+"--");

        return row;
    }
    static class ValeursDefini
    {
        TextView tx_mpx,tx_rds,tx_al,tx_ar,tx_frequence,tx_pilots;

    }
}

我希望通过使用我的类Valeur在getter上获取mpx的值，在textView4上只显示我的变量mpx

---

谢谢

您没有初始化

Valeurs-Valeurs

E/AndroidRuntime: FATAL EXCEPTION: main
              Process: com.suprem.myapplication, PID: 2288
              java.lang.RuntimeException: Unable to start activity ComponentInfo{com.suprem.myapplication/com.suprem.myapplication.AfficheurListView}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.suprem.myapplication.Valeurs.getMpx()' on a null object reference
                  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
                  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
                  at android.app.ActivityThread.access$800(ActivityThread.java:151)
                  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
                  at android.os.Handler.dispatchMessage(Handler.java:102)
                  at android.os.Looper.loop(Looper.java:135)
                  at android.app.ActivityThread.main(ActivityThread.java:5254)
                  at java.lang.reflect.Method.invoke(Native Method)
                  at java.lang.reflect.Method.invoke(Method.java:372)
                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
               Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.suprem.myapplication.Valeurs.getMpx()' on a null object reference
                  at com.suprem.myapplication.AfficheurListView$override.onCreate(AfficheurListView.java:36)
                  at com.suprem.myapplication.AfficheurListView$override.access$dispatch(AfficheurListView.java)
                  at com.suprem.myapplication.AfficheurListView.onCreate(AfficheurListView.java:0)
                  at android.app.Activity.performCreate(Activity.java:5990)
                  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
                  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
                  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387) 
                  at android.app.ActivityThread.access$800(ActivityThread.java:151) 
                  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303) 
                  at android.os.Handler.dispatchMessage(Handler.java:102) 
                  at android.os.Looper.loop(Looper.java:135) 
                  at android.app.ActivityThread.main(ActivityThread.java:5254) 
                  at java.lang.reflect.Method.invoke(Native Method) 
                  at java.lang.reflect.Method.invoke(Method.java:372) 
                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) 
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)