标签：json java android listview android-search
1.我的搜索功能使用edittext工作正常,但是例如,如果我输入“1”而不是删除它,listview显示为null,我怎样才能使listview在输入内容后再次显示JSON然后将其删除？
2.如果我改为搜索COUNTRY而不是RANK,我需要输入像“INDIA”这样的完整字符,我怎么才能输入“in”然后才能显示INDIA？
谢谢
MainActivity.java
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();
}
}
}
ListViewAdapter.java
import android.content.Context;
import android.content.Intent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.HashMap;
public class ListViewAdapter extends BaseAdapter {
Context context;
LayoutInflater inflater;
public ArrayList<HashMap<String, String>> data;
ImageLoader imageLoader;
HashMap<String, String> resultp = new HashMap<String, String>();
public ListViewAdapter(Context context,
ArrayList<HashMap<String, String>> arraylist) {
this.context = context;
data = arraylist;
imageLoader = new ImageLoader(context);
}
@Override
public int getCount() {
return data.size();
}
@Override
public Object getItem(int position) {
return null;
}
@Override
public long getItemId(int position) {
return 0;
}
public View getView(final int position, View convertView, ViewGroup parent) {
// Declare Variables
TextView rank;
TextView country;
TextView population;
TextView url;
ImageView flag;
inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View itemView = inflater.inflate(R.layout.listview_item, parent, false);
// Get the position
resultp = data.get(position);
// Locate the TextViews in listview_item.xml
rank = (TextView) itemView.findViewById(R.id.rank);
country = (TextView) itemView.findViewById(R.id.country);
population = (TextView) itemView.findViewById(R.id.population);
url=(TextView)itemView.findViewById(R.id.url);
// Locate the ImageView in listview_item.xml
flag = (ImageView) itemView.findViewById(R.id.flag);
// Capture position and set results to the TextViews
rank.setText(resultp.get(MainActivity.RANK));
country.setText(resultp.get(MainActivity.COUNTRY));
population.setText(resultp.get(MainActivity.POPULATION));
url.setText(resultp.get(MainActivity.URL));
// Capture position and set results to the ImageView
// Passes flag images URL into ImageLoader.class
imageLoader.DisplayImage(resultp.get(MainActivity.FLAG), flag);
// Capture ListView item click
itemView.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// Get the position
resultp = data.get(position);
Intent intent = new Intent(context, SingleItemView.class);
// Pass all data rank
intent.putExtra("rank", resultp.get(MainActivity.RANK));
// Pass all data country
intent.putExtra("country", resultp.get(MainActivity.COUNTRY));
// Pass all data population
intent.putExtra("population",resultp.get(MainActivity.POPULATION));
intent.putExtra("url",resultp.get(MainActivity.URL));
// Pass all data flag
intent.putExtra("flag", resultp.get(MainActivity.FLAG));
// Start SingleItemView Class
context.startActivity(intent);
}
});
return itemView;
}
}
在下面编辑此代码,谢谢
import android.app.ListActivity;
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 ListActivity {
// 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;
String globalQuery="";
ArrayList<HashMap<String, String>> globalList = new ArrayList<HashMap<String, String>>();
ListViewAdapter globalListAdapter,globalAdapter=null;
public void filteredList()
{
//First of all checks for our globalList is not a null one.
if(globalList!=null)
{
ArrayList<HashMap<String, String>> tempList = new ArrayList<HashMap<String, String>>();
//Checks our search term is empty or not.
ListViewAdapter globalAdapter = null;
if(!globalQuery.trim().equals(""))
{
boolean isThereAnyThing=false;
for(int i=0;i<globalList.size();i++)
{
//Get the value of globalList that is HashMap indexed at i.
HashMap<String, String> tempMap=globalList.get(i);
//Now getting all your HashMap values into local variables.
String rank=tempMap.get(MainActivity.RANK);
String country=tempMap.get(MainActivity.COUNTRY);
String population=tempMap.get(MainActivity.POPULATION);
String url=tempMap.get(MainActivity.URL);
String flag=tempMap.get(MainActivity.FLAG);
//Now all the core checking goes here for which one of these was typed like rank or country or population .....
if(rank.regionMatches(true, 0, globalQuery,0, globalQuery.length()) || country.regionMatches(true, 0, globalQuery,0, globalQuery.length()) || population.regionMatches(true, 0, globalQuery,0, globalQuery.length()) || url.regionMatches(true, 0, globalQuery,0, globalQuery.length()) || flag.regionMatches(true, 0, globalQuery,0, globalQuery.length()))
{
//If anything matches then it will add to tempList
tempList.add(tempMap);
isThereAnyThing=true;
}
}
//Checks for is there anything matched from the ArrayList with the user type search query
if(isThereAnyThing)
{
//then set the globalAdapter with the new HashMaps tempList
globalAdapter = new ListViewAdapter(MainActivity.this, tempList);
listview.setAdapter(globalAdapter);
setListAdapter(globalAdapter);
((ListViewAdapter)globalAdapter).notifyDataSetChanged();
}
else
{
//If else set list adapter to null
setListAdapter(null);
}
}
else
{
// Do something when there's no input
if(globalAdapter==null)
{
//If no user inputs then it will list everything in the globalList.
justListAll();
}
else
{
final ListViewAdapter finalGlobalAdapter = globalAdapter;
runOnUiThread(new Runnable()
{
public void run()
{
((ListViewAdapter) finalGlobalAdapter).notifyDataSetChanged();
}
});
}
}
// updating listview
}
}
@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) {
if (s.toString().length() > 0) {
// Search
globalQuery=s.toString();
//This method will filter all your categories just calling this method.
filteredList();
} else {
globalQuery="";
//If the text is empty the list all the content of the list adapter
justListAll();
}
}
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();
if(searchString.equals("")){new DownloadJSON().execute();}
else{
for (int i = 0; i < arraylist.size(); i++) {
String currentString = arraylist.get(i).get(MainActivity.COUNTRY);
if (searchString.contains(currentString)) {
//pass the character-sequence instead of 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();
}
}
public void justListAll()
{
ListViewAdapter globalAdapter = new ListViewAdapter(MainActivity.this, globalList);
listview.setAdapter(adapter);
setListAdapter(globalAdapter);
((ListViewAdapter)globalAdapter).notifyDataSetChanged();
}
}
解决方法:
感谢您按照SO指南以良好的方式提出问题.
我相信这会解决你的问题.
//First of all declare a global variables
String globalQuery="";
ArrayList<HashMap<String, String>> globalList = new ArrayList<HashMap<String, String>>();
ListViewAdapter globalListAdapter;
public void afterTextChanged(Editable s) {
if (s.toString().length() > 0) {
// Search
globalQuery=s.toString();
//This method will filter all your categories just calling this method.
filteredList();
} else {
globalQuery="";
//If the text is empty the list all the content of the list adapter
justListAll();
}
}
public void justListAll()
{
globalAdapter = new ListViewAdapter(MainActivity.this, globalList);
listview.setAdapter(adapter);
setListAdapter(globalAdapter);
((ListViewAdapter)globalAdapter).notifyDataSetChanged();
}
public void filteredList()
{
//First of all checks for our globalList is not a null one.
if(globalList!=null)
{
ArrayList<HashMap<String, String>> tempList = new ArrayList<HashMap<String, String>>();
//Checks our search term is empty or not.
if(!globalQuery.trim().equals(""))
{
boolean isThereAnyThing=false;
for(int i=0;i<globalList.size();i++)
{
//Get the value of globalList that is HashMap indexed at i.
HashMap<String, String> tempMap=globalList.get(i);
//Now getting all your HashMap values into local variables.
String rank=tempMap.get(MainActivity.RANK);
String country=tempMap.get(MainActivity.COUNTRY);
String population=tempMap.get(MainActivity.POPULATION);
String url=tempMap.get(MainActivity.URL);
String flag=tempMap.get(MainActivity.FLAG);
//Now all the core checking goes here for which one of these was typed like rank or country or population .....
if(rank.regionMatches(true, 0, globalQuery,0, globalQuery.length()) || country.regionMatches(true, 0, globalQuery,0, globalQuery.length()) || population.regionMatches(true, 0, globalQuery,0, globalQuery.length()) || url.regionMatches(true, 0, globalQuery,0, globalQuery.length()) || flag.regionMatches(true, 0, globalQuery,0, globalQuery.length()))
{
//If anything matches then it will add to tempList
tempList.add(tempMap);
isThereAnyThing=true;
}
}
//Checks for is there anything matched from the ArrayList with the user type search query
if(isThereAnyThing)
{
//then set the globalAdapter with the new HashMaps tempList
globalAdapter = new ListViewAdapter(MainActivity.this, tempList);
listview.setAdapter(globalAdapter);
setListAdapter(globalAdapter);
((ListViewAdapter)globalAdapter).notifyDataSetChanged();
}
else
{
//If else set list adapter to null
setListAdapter(null);
}
}
else
{
// Do something when there's no input
if(globalAdapter==null)
{
//If no user inputs then it will list everything in the globalList.
justListAll();
}
else
{
runOnUiThread(new Runnable()
{
public void run()
{
((ListViewAdapter)globalAdapter).notifyDataSetChanged();
}
});
}
}
// updating listview
}
}
只需要执行的操作就是将所有JSON解析值填充到全局ArrayList globalList中.
希望它通过额外的包装回答整个问题.
标签：json,java,android,listview,android-search 来源： https://codeday.me/bug/20190628/1317423.html
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