活动中的列表视图不会显示

Question

我有一个ListView的活动和一个自定义适配器。我确信我的mItems listview适配器不为null。但是，我一直收到NullPointerException错误。

这是我的主要活动

public class Profile extends AppCompatActivity {
private static String PageType;
ImageView imageToUpload;
private ImageView mImageView;
private String Enc_Pass="";
private List<ListProfileItem> mItems;
private ListProfileItem item;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_profile);

    URLService = getString(R.string.URLService);
    Enc_Pass = getString(R.string.password_encryption);
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    SharedPreferences pref = getSharedPreferences("MyPref", MODE_PRIVATE);
     strUserId = pref.getString("userId", null);
     strPassword = pref.getString("Password", null);
    code_comp = pref.getString("CompanyCode",null);
    String Status = "";

    final ListView lv = (ListView)findViewById(R.id.lvProfile);
    getMedicalBalance();
    lv.setAdapter(new ListProfileAdapter(this,mItems));
}
public Profile() {
}

@Override
public boolean onPrepareOptionsMenu(Menu menu) {
    menu.clear();
    menu.add(Menu.NONE, 0, 0, "Save").setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);
    return super.onPrepareOptionsMenu(menu);

}
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_profile);


    final ListView lv = (ListView)findViewById(R.id.lvProfile);
    getMedicalBalance();
    lv.setAdapter(new ListProfileAdapter(this,mItems));
}
private void getMedicalBalance(){
    try{
        String encc  = "";
        try {
         //  encrypt for parameter
        }catch (GeneralSecurityException e){
            //handle error
        }

        RESTClient client = new RESTClient(URLService+"get? method=methodname&value="
                + encc);

        client.Execute(RESTClient.RequestMethod.GET);
        String response = client.getResponse();
        JSONParser jsonParser = new JSONParser();
        JSONObject jsonObject = (JSONObject) jsonParser.parse(response);
        mItems = new ArrayList<ListProfileItem>();

        String Status = jsonObject.get("Status").toString();
        if (Status == "true") {
JSONParser parser = new JSONParser();
            JSONArray structure = (JSONArray) parser.parse(dataku);
            for (int i = 0; i < structure.size(); i++) {
                JSONObject data = (JSONObject) structure.get(i);

                item = new ListProfileItem();
                item.claimpostamount = data.get("max_limit_per_year").toString();
                item.claimpostname = data.get("claim_post_name").toString();
                mItems.add(item);
            }
            // initialize and set the list adapter
        }
    }
    catch(Exception e){
        e.printStackTrace();

    }
}

这是XML

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/fragment_profile"
android:layout_width="match_parent"
android:tag="tagprofile"
android:layout_height="match_parent"
android:background="#ffffff">

<ScrollView
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <LinearLayout
        android:id="@+id/linLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
        android:orientation="vertical">

        <de.hdodenhof.circleimageview.CircleImageView
            android:id="@+id/imageToUpload"
            android:layout_width="200dp"
            android:layout_height="200dp"
            android:layout_gravity="center_horizontal"
            android:src="@drawable/ic_menu_camera"
            android:layout_marginTop="10dp" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:text="Profile Detail"
            android:id="@+id/tvProfileDetail"
            android:layout_marginTop="30dp" />

        <ListView
            xmlns:android="http://schemas.android.com/apk/res/android"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:id="@+id/lvProfile"
            android:choiceMode="singleChoice"
            android:nestedScrollingEnabled="false"
            android:longClickable="true"
            android:paddingTop="0dp"
            android:layout_marginTop="0dp"
            android:headerDividersEnabled="false"
            android:divider="@null"
            android:dividerHeight="0dp"/>
    </LinearLayout>

</ScrollView>
</RelativeLayout>

这是我的自定义列表视图

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="match_parent"
android:background="@color/white">

    <LinearLayout
        android:layout_width="0dp"
        android:layout_weight="0.8"
        android:orientation="vertical"
        android:layout_height="wrap_content">

        <!--All textViews here-->
        <TextView
            android:layout_width="150dp"
            android:paddingTop="15dp"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:text="Type"
            android:textSize="12dp"
            android:fontFamily="sans-serif"
            android:textColor="@color/black"
            android:id="@+id/tvJenisBalance"
            android:width="130dp" />

        <TextView
            android:layout_width="150dp"
            android:layout_weight="1"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:text="Date"
            android:fontFamily="sans-serif"
            android:id="@+id/tvAmountBalance"
            android:textSize="15dp"
            android:width="130dp" />
    </LinearLayout>
 </RelativeLayout>

这是我的listviewadapter

public class ListProfileAdapter extends ArrayAdapter<ListProfileItem> {
public ListProfileAdapter(Context context, List<ListProfileItem> items)
{
    super(context, R.layout.style_fragment_list_profile, items);
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    ViewHolder viewHolder;

    if(convertView == null) {
        // inflate the GridView item layout
        LayoutInflater inflater = LayoutInflater.from(getContext());
        convertView = inflater.inflate(R.layout.style_fragment_list_profile, parent, false);

        // initialize the view holder
        viewHolder = new ViewHolder();
        viewHolder.tvclaimpostamount = (TextView) convertView.findViewById(R.id.tvAmountBalance);
        viewHolder.tvclaimpostname = (TextView)  convertView.findViewById(R.id.tvJenisBalance);

        convertView.setTag(viewHolder);
    } else {
        // recycle the already inflated view
        viewHolder = (ViewHolder) convertView.getTag();
    }

    // update the item view
    ListProfileItem item = getItem(position);
    viewHolder.tvclaimpostname.setText(item.claimpostname);
    viewHolder.tvclaimpostamount.setText(item.claimpostamount);

    return convertView;
  }
  private static class ViewHolder {
    TextView tvclaimpostname;
    TextView tvclaimpostamount;

 }
 }

任何帮助都会受到赞赏。