listadapterを使用してListViewを更新しますか？

Question

基本データを変更するたびにListViewを更新したいと思います。

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 

    mListUsers = getUsers(); 
lvList = (ListView) findViewById(R.id.event_list); 
lvList.setAdapter(new ListAdapter(mContext, R.id.event_list, mListUsers)); 

    btn_next=(Button)findViewById(R.id.btn_next); 
btn_next.setOnClickListener(new OnClickListener() { 

@Override 
public void onClick(View v) { 
// TODO Auto-generated method stub 
SimpleDateFormat postFormater = new SimpleDateFormat("dd-MMM-yyyy",Locale.ENGLISH); 
String newDateStr = lbl_date.getText().toString();   
Calendar c = Calendar.getInstance(); 
try { 
c.setTime(postFormater.parse(newDateStr)); 
} catch (ParseException e) { 
// TODO Auto-generated catch block 
e.printStackTrace(); 
} 
c.add(Calendar.DATE, 1); // number of days to add 
newDateStr = postFormater.format(c.getTime()); 
lbl_date.setText(newDateStr.toString()); 

mListUsers = getUsers(); 
lvList = (ListView) findViewById(R.id.event_list); 
lvList.setAdapter(new ListAdapter(mContext, R.id.event_list, mListUsers)); 
} 
}); 

}

public ArrayList<main_list_item> getUsers(){     
DBAdapter dbAdapter=DBAdapter.getDBAdapterInstance(this); 
try { 
      dbAdapter.createDataBase(); 
     } catch (IOException e) { 
      Log.i("*** select ",e.getMessage()); 
     } 
     dbAdapter.openDataBase(); 

     SimpleDateFormat curFormater1 = new SimpleDateFormat("yyyy-MM-dd"); 
     String dateString = curFormater1.format(new Date(lbl_date.getText().toString())); 
     String query;  
     if(all==1){ 
      query="SELECT id,dateS, dateE, (select eventname from tbEvent_name where tbEvent_name.id=eventId)as event FROM tbTransaction"; 
     } 
     else{ 
      query="SELECT id,dateS, dateE, (select eventname from tbEvent_name where tbEvent_name.id=eventId)as event FROM tbTransaction WHERE SUBSTR(sDate,1,10)='"+dateString+"'"; 
     } 

     ArrayList<ArrayList<String>> stringList = dbAdapter.selectRecordsFromDBList(query, null); 
     dbAdapter.close(); 

     SimpleDateFormat curFormater = new SimpleDateFormat("yyyy-MM-dd",Locale.ENGLISH); 
     Date dateObj = null; 

     ArrayList<main_list_item> usersList = new ArrayList<main_list_item>(); 
     for (int i = 0; i < stringList.size(); i++) { 
      ArrayList<String> list = stringList.get(i); 
      main_list_item user = new main_list_item(); 
      try { 
       user.id=Integer.parseInt(list.get(0)); 
       user.event= list.get(3); 

     String newDateStr1 = postFormater1.format(dateObj); 

       user.dateS=list.get(1); 
       user.dateE=list.get(2); 

      } catch (Exception e) { 
       e.printStackTrace(); 
      } 
      usersList.add(user); 
     } 
     return usersList; 
    } 

// ***ListAdapter*** 
    private class ListAdapter extends ArrayAdapter<main_list_item> { // --CloneChangeRequired 
     private ArrayList<main_list_item> mList; // --CloneChangeRequired 
     private Context mContext; 

     public ListAdapter(Context context, int textViewResourceId,ArrayList<main_list_item> list) { // --CloneChangeRequired 
      super(context, textViewResourceId, list); 
      this.mList = list; 
      this.mContext = context; 
     } 

     public View getView(int position, View convertView, ViewGroup parent){ 
      View view = convertView; 
      try{ 
      if (view == null) { 
       LayoutInflater vi = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
       view = vi.inflate(R.layout.main_list_item, null); // --CloneChangeRequired(list_item) 
      } 
      final main_list_item listItem = mList.get(position); // --CloneChangeRequired     
      if (listItem != null) { 
       // setting list_item views      
       ((TextView) view.findViewById(R.id.lbl_id)).setText(listItem.getId()+""); 

       ((TextView) view.findViewById(R.id.lbl_event)).setText(listItem.getEvent()+""); 
       ((TextView) view.findViewById(R.id.lbl_sdate)).setText(listItem.getsDate()+""); 
       ((TextView) view.findViewById(R.id.lbl_edate)).setText(listItem.geteDate()+""); 

      }}catch(Exception e){ 
       e.printStackTrace(); 
      } 

      return view; 
     }  
    } 

その正しい方法である：以下 例を参照してください？

このコードでは、 'btn_next'をクリックするとlistviewが更新されます。

また、2つの部分を分けて、見出しを付けたいと思います。

事前に

おかげ

Uncaught handler: thread main exiting due to uncaught exception 
java.lang.NullPointerException 
at com.apt.eTrack.ETrackActivity$4.onClick(ETrackActivity.java:153) 
at android.view.View.performClick(View.java:2344) 
at android.view.View.onTouchEvent(View.java:4133) 
at android.widget.TextView.onTouchEvent(TextView.java:6510) 
at android.view.View.dispatchTouchEvent(View.java:3672) 
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:882) 
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:882) 
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:882) 
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:882) 
at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1712) 
at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1202) 
at android.app.Activity.dispatchTouchEvent(Activity.java:1987) 
at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1696) 
at android.view.ViewRoot.handleMessage(ViewRoot.java:1658) 
at android.os.Handler.dispatchMessage(Handler.java:99) 
at android.os.Looper.loop(Looper.java:123) 
at android.app.ActivityThread.main(ActivityThread.java:4203) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:521) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:791) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:549) 
at dalvik.system.NativeStart.main(Native Method) 
Unable to open stack trace file '/data/anr/traces.txt': Permission denied 

Answer 1

static ListAdapter mListAdapter; 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 

    mListUsers = getUsers(); 
    mListAdapter=new ListAdapter(mContext, R.id.event_list, mListUsers); 
    lvList = (ListView) findViewById(R.id.event_list); 
    lvList.setAdapter(mListAdapter); 

    btn_next=(Button)findViewById(R.id.btn_next); 
    btn_next.setOnClickListener(new OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      // TODO Auto-generated method stub 
      SimpleDateFormat postFormater = new SimpleDateFormat("dd-MMM-yyyy",Locale.ENGLISH); 
      String newDateStr = lbl_date.getText().toString();   
      Calendar c = Calendar.getInstance(); 
      try { 
       c.setTime(postFormater.parse(newDateStr)); 
      } catch (ParseException e) { 
       // TODO Auto-generated catch block 
       e.printStackTrace(); 
      } 
      c.add(Calendar.DATE, 1); // number of days to add 
      newDateStr = postFormater.format(c.getTime()); 
      lbl_date.setText(newDateStr.toString()); 

      mListUsers = getUsers(); 
      mListAdapter.notifyDataSetChanged(); 
     } 
    }); 
}