andorid: simple adapter null pointer : i have an app that i want to retrive data from my server with php json and get method , i use simple adapter and json downloader and json parser for this app ,

i have problem with my simple adapter to show my data in my listView ,

when i run my project it occure with crash and show some errors

this is in main activity:

  

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    
        mTextMessage = (TextView) findViewById(R.id.message);
        BottomNavigationView navigation = (BottomNavigationView) findViewById(R.id.navigation);
        navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);
        set_bedehkariha_list();
    
    
    }
    
    public void set_bedehkariha_list(){
        JSONDownloader jsdl = new JSONDownloader();
        String temp = jsdl.downloadURL( "http://famila1.ir/khabgah/get_khabgah_cash.php");
    
        List<HashMap<String,Object>> cash = new ArrayList<HashMap<String, Object>>();
        cashParser cashparse = new cashParser();
        cash= cashparse.parse(temp);
    
        String[] from = {"hazine","tozihat","hazine_shareTo","who_paid","date"};
        int[] to = {R.id.mablaq_hazine,R.id.babate_hazine,R.id.moshtarak_ba,R.id.pardakhtaz,R.id.tarikh_hazine};
        SimpleAdapter myadapter = new SimpleAdapter(MainActivity.this,cash, R.layout.cash_list_row,from,to);
        ListView lv = (ListView) findViewById(R.id.list_bedehkariha);
        lv.setAdapter(myadapter);
    }

this is jsonDownloader:

  

      public class JSONDownloader
    {
        public String downloadURL( String strUrl )
        {
            String data = "";

        try
        {
            URL url = new URL( strUrl );

            HttpURLConnection connection = (HttpURLConnection) url.openConnection();

            connection.setReadTimeout(10000);

            connection.setConnectTimeout(15000);

            connection.setRequestMethod("GET");

            connection.setDoInput(true);

            connection.connect();

            InputStream myStream = connection.getInputStream();

            BufferedReader br = new BufferedReader( new InputStreamReader( myStream ) );

            StringBuilder sb = new StringBuilder();

            String line;

            while ( ( line = br.readLine() ) != null )
            {
                sb.append( line );
            }

            data = sb.toString();

            br.close();

            connection.disconnect();

            myStream.close();
        }
        catch ( Exception e )
        {
            /*
              *Log.i( "MatiMessage" , "error in JSONDownloader in downloadURL() -> " + e.toString() );
              */
        }

        return data;
    }

and this is my JsonParser:

        public List<HashMap<String , Object>> parse( String json )
    {
        List<HashMap<String , Object>> all_cash = new ArrayList<>();

        try
        {
            JSONObject jObj = new JSONObject( json );

            JSONArray jArr = jObj.getJSONArray( "cash" );

            for( int i = 0; i < jArr.length(); i ++ )
            {
                JSONObject temp = jArr.getJSONObject( i );

                HashMap<String , Object> cash = new HashMap<String , Object>();

                cash.put( "id" , temp.getString( "id" ) );
                cash.put( "member_id" , temp.getString( "member_id" ) );
                cash.put( "hazine" , temp.getString( "hazine" ) );
                cash.put( "date" , temp.getString( "date" ) );
                cash.put( "hazine_shareTo" , "hazine_shareTo" );
                cash.put( "tozihat" , temp.getString( "tozihat" ) );
                cash.put( "who_paid" , temp.getString( "who_paid" ) );
                all_cash.add( cash );
            }

        }
        catch ( Exception e )
        {
            /*
             * Log.i( "MatiMessage" , "error in cashParser in parse() -> " + e.toString() );
             */
        }

        return ( all_cash );
    }


and this is my error in main activity when i run the app :

>     java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.aqamamad.myapplication/com.example.aqamamad.myapplication.MainActivity}:
> java.lang.NullPointerException: Attempt to invoke virtual method 'void
> android.widget.ListView.setAdapter(android.widget.ListAdapter)' on a
> null object reference


