1.我的搜索功能只适用于filter int(例如:rank)如果我想过滤char(例如:country name),应该如何更改此代码?Android JSON列表视图搜索功能(更新)
2.当我在mEdittext中输入某些内容而不是删除它时,listview变为空,如果mEdittext为空,我怎么能再次看到json listview?
对于现在的过滤器工作正常,我只是无法弄清楚如何解决这两个question.thanks
import android.app.Activity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.util.Log;
import android.widget.EditText;
import android.widget.ListView;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.HashMap;
public class MainActivity extends Activity {
// Declare Variables
JSONObject jsonobject;
JSONArray jsonarray;
ListView listview;
ListViewAdapter adapter;
ProgressDialog mProgressDialog;
ArrayList<HashMap<String, String>> arraylist;
static String RANK = "rank";
static String COUNTRY = "country";
static String POPULATION = "population";
static String URL="url";
static String FLAG = "flag";
EditText mEditText;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Get the view from listview_main.xml
setContentView(R.layout.listview_main);
// Execute DownloadJSON AsyncTask
new DownloadJSON().execute();
mEditText = (EditText) findViewById(R.id.inputSearch);
mEditText.addTextChangedListener(new TextWatcher() {
public void afterTextChanged(Editable s) {
}
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
public void onTextChanged(CharSequence s, int start, int before, int count) {
ArrayList<HashMap<String, String>> arrayTemplist = new ArrayList<HashMap<String, String>>();
String searchString = mEditText.getText().toString();
for (int i = 0; i < arraylist.size(); i++) {
String currentString = arraylist.get(i).get(MainActivity.RANK);
if (searchString.equalsIgnoreCase(currentString)) {
arrayTemplist.add(arraylist.get(i));
}
}
adapter = new ListViewAdapter(MainActivity.this, arrayTemplist);
listview.setAdapter(adapter);
}
});
}
// DownloadJSON AsyncTask
private class DownloadJSON extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Create a progressdialog
mProgressDialog = new ProgressDialog(MainActivity.this);
// Set progressdialog title
mProgressDialog.setTitle("Android JSON Parse Tutorial");
// Set progressdialog message
mProgressDialog.setMessage("Loading...");
mProgressDialog.setIndeterminate(false);
// Show progressdialog
mProgressDialog.show();
}
@Override
protected Void doInBackground(Void... params) {
// Create an array
arraylist = new ArrayList<HashMap<String, String>>();
// Retrieve JSON Objects from the given URL address
jsonobject = JSONfunctions
.getJSONfromURL("http://ndublog.twomini.com/123.txt.txt");
try {
// Locate the array name in JSON
jsonarray = jsonobject.getJSONArray("worldpopulation");
for (int i = 0; i < jsonarray.length(); i++) {
HashMap<String, String> map = new HashMap<String, String>();
jsonobject = jsonarray.getJSONObject(i);
// Retrive JSON Objects
map.put("rank", jsonobject.getString("rank"));
map.put("country", jsonobject.getString("country"));
map.put("population", jsonobject.getString("population"));
map.put("url",jsonobject.getString("url"));
map.put("flag", jsonobject.getString("flag"));
// Set the JSON Objects into the array
arraylist.add(map);
}
} catch (JSONException e) {
Log.e("Error", e.getMessage());
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Void args) {
// Locate the listview in listview_main.xml
listview = (ListView) findViewById(R.id.listview);
// Pass the results into ListViewAdapter.java
adapter = new ListViewAdapter(MainActivity.this, arraylist);
// Set the adapter to the ListView
listview.setAdapter(adapter);
// Close the progressdialog
mProgressDialog.dismiss();
}
}
}
似乎'adapter'为空。 –
但适配器为空? –
尝试检查'if(MainActivity.this.adapter!= null){...}' –