Question

尝试在列表视图中显示已过滤的列表时出现问题。我在过滤后打印出数据并且它实际上是正确的，但它不会显示在我的ListView上，请问我做错了什么？我的代码在

之下

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.drawable.Icon;
import android.media.Image;
import android.util.Base64;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Filter;
import android.widget.BaseAdapter;
import android.widget.Filterable;
import android.widget.ImageView;
import android.widget.TextView;

import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.HashMap;

public class SchoolListAdapter extends BaseAdapter implements Filterable {

private Activity activity;
ArrayList<HashMap<String, String>> data;
ArrayList<HashMap<String, String>> displayedData;
private static LayoutInflater inflater=null;

public SchoolListAdapter(Activity a, ArrayList<HashMap<String, String>> d) {
    activity = a;
    data=d;
    displayedData = d;
    inflater = LayoutInflater.from(a);
}

public int getCount() {
    return data.size();
}

public Object getItem(int position) {
    return position;
}

public long getItemId(int position) {
    return position;
}

public View getView(int position, View convertView, ViewGroup parent) {
    View vi=convertView;
    if(convertView==null) {
        vi = inflater.inflate(R.layout.school_details_list, null);
    }

    ImageView schoolLogo = (ImageView) vi.findViewById(R.id.schoolLogo);
    TextView lblSchoolId = (TextView)vi.findViewById(R.id.lblSchoolId);
    TextView lblSchoolName = (TextView)vi.findViewById(R.id.lblSchoolName);

    HashMap<String, String> school = data.get(position);
    // Setting all values in listview
    lblSchoolId.setText(school.get("id"));
    lblSchoolName.setText(school.get("name"));
    String logo = school.get("logo");

    byte []img = Base64.decode(logo,Base64.DEFAULT);
    Bitmap bmp = BitmapFactory.decodeByteArray(img, 0, img.length);
    schoolLogo.setImageBitmap(bmp);

    return vi;
}

@Override
public Filter getFilter() {
    Filter filter = new Filter() {

        @Override
        protected void publishResults(CharSequence constraint,FilterResults results) {
            if(results.count == 0){
                notifyDataSetInvalidated();
            }else{
                displayedData = (ArrayList<HashMap<String, String>>) results.values; // has the filtered values
                notifyDataSetChanged();  // notifies the data with new filtered values
            }
        }

        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
            FilterResults results = new FilterResults();        // Holds the results of a filtering operation in values
            ArrayList<HashMap<String, String>> FilteredArrList = new ArrayList();

            if (data == null) {
                data = new ArrayList(displayedData); // saves the original data in data
            }

            /********
             *
             *  If constraint(CharSequence that is received) is null returns the data(Original) values
             *  else does the Filtering and returns FilteredArrList(Filtered)  
             *
             ********/
            if (constraint == null || constraint.length() == 0) {

                // set the Original result to return  
                results.count = data.size();
                results.values = data;
            } else {
                constraint = constraint.toString().toUpperCase();
                HashMap <String, String>schools = new HashMap();
                for (int i = 0; i < data.size(); i++) {
                    String dat = data.get(i).get("name");
                    if(dat.toString().matches(".*"+constraint+".*")){
                        schools.put("id",data.get(i).get("id"));
                        schools.put("name",data.get(i).get("name"));
                        schools.put("logo",data.get(i).get("logo"));
                        FilteredArrList.add(schools);
                    }
                }
                // set the Filtered result to return
                results.count = FilteredArrList.size();
                results.values = FilteredArrList;

            }
            return results;
        }
    };
    return filter;
}
}

import android.app.Activity;
import android.app.ListActivity;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.AsyncTask;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;

import org.json.JSONArray;
import org.json.JSONObject;

import java.util.ArrayList;
import java.util.HashMap;

public class SelectSchoolActivity extends ListActivity implements AdapterView.OnItemClickListener {

private ProgressDialog pDialog;
private ListView lv;
private SharedPreferences sharedPreferences;
public static String SCHOOLING_PREFERENCES = "SCHOOL_PREF";
private ArrayList<HashMap<String, String>> schoolList;
private EditText txtSearch;
private SchoolListAdapter adapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_select_school);
    sharedPreferences = getSharedPreferences(SCHOOLING_PREFERENCES, Context.MODE_PRIVATE);
    txtSearch = (EditText)findViewById(R.id.txtSearch);
    schoolList = new ArrayList();
    if(sharedPreferences.contains("school")){
        Intent intent = new Intent(SelectSchoolActivity.this, LoginActivity.class);
        startActivity(intent);
        finish();
    }else{
        new GetSchoolList(SelectSchoolActivity.this).execute();
        lv = getListView();
        lv.setOnItemClickListener(this);


        // Add Text Change Listener to EditText
        txtSearch.addTextChangedListener(new TextWatcher() {

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {
                // Call back the Adapter with current character to Filter
                adapter.getFilter().filter(s.toString());
            }

            @Override
            public void beforeTextChanged(CharSequence s, int start, int count,int after) {
            }

            @Override
            public void afterTextChanged(Editable s) {
            }
        });
    }
}


public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
    String school = ((TextView)view.findViewById(R.id.lblSchoolId)).getText().toString();
    SharedPreferences.Editor editor = sharedPreferences.edit();
    editor.putString("school", school);
    editor.commit();
    Intent intent = new Intent(SelectSchoolActivity.this, LoginActivity.class);
    startActivity(intent);
    finish();
}

private class GetSchoolList extends AsyncTask<Void, Void, Void> {

    private Activity context;

    public GetSchoolList(Activity context){
        this.context = context;
    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        // Showing progress dialog
        pDialog = new ProgressDialog(context);
        pDialog.setMessage("Please wait...");
        pDialog.setCancelable(false);
        pDialog.show();
    }

    @Override
    protected Void doInBackground(Void... arg0) {

        // Creating service handler class instance
        ServiceHandler sh = new ServiceHandler();
        String url = "http://192.168.34.1:8085/SchoolWebService/rest/Student/school_list";
        // Making a request to url and getting response
        String details = sh.makeServiceCall(url, ServiceHandler.GET);

        if (details != null) {
            try {
                JSONArray results = new JSONArray(details);
                for(int i = 0; i<results.length(); i++) {
                    JSONObject c = results.getJSONObject(i);
                    String id = c.getString("id");
                    String name = c.getString("name");
                    String logo = c.getString("logo");

                    // tmp hashmap for single feeDetails
                    HashMap <String, String>school = new HashMap();
                    school.put("id", id);
                    school.put("name", name);
                    school.put("logo", logo);

                    schoolList.add(school);
                }
            } catch (Exception e) {
                Log.e("Exception", Log.getStackTraceString(e));
            }
        } else {
            //snackbar.setText("Connection Failed!").show();
        }

        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        super.onPostExecute(result);
        // Dismiss the progress dialog
        if (pDialog.isShowing()) {
            pDialog.dismiss();
        }

        adapter = new SchoolListAdapter(context, schoolList);
        setListAdapter(adapter);
    }
}

}

Answer 1

@medhdj在我的代码中指出并出错，因此我能够找到并解决问题。请参阅他的评论

在ListView上显示过滤的数据

1 个答案: