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我有一个ListView。我想动态地改变listview的内容。我用“adapter.notifyDataSetChanged（）;”改变内容。它清爽但不清除列表视图，而是将它附加到以前的结果。我想要的是应删除以前的内容，并显示新的结果。的ListView不明确设置新值
我不能明白的地方是我的错误，我所缺少的。
我会心存感激，如果有人可以帮我了这一点。
这里是我的代码
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.slider);
t1 = (TextView) findViewById(R.id.noRec);
// list = (ListView) findViewById(R.id.listView1);
list = getListView();
cb1 = (CheckBox) findViewById(R.id.checkBox1);
cb2 = (CheckBox) findViewById(R.id.checkBox2);
cb3 = (CheckBox) findViewById(R.id.checkBox3);
cb4 = (CheckBox) findViewById(R.id.checkBox4);
cb5 = (CheckBox) findViewById(R.id.checkBox5);
cb6 = (CheckBox) findViewById(R.id.checkBox6);
cb7 = (CheckBox) findViewById(R.id.checkBox7);
cb8 = (CheckBox) findViewById(R.id.checkBox8);
cb9 = (CheckBox) findViewById(R.id.checkBox9);
cb10 = (CheckBox) findViewById(R.id.checkBox10);
d = (Spinner) findViewById(R.id.drive);
spn1 = (Spinner) findViewById(R.id.spinner1);
ArrayAdapter<String> adap = new ArrayAdapter<String>(this,
R.layout.spin_adptr, search);
adap.setDropDownViewResource(R.layout.spin_drop);
spn1.setAdapter(adap);
spn1.setOnItemSelectedListener(this);
int spinner_id = sid.getInt("SpnID", 0);
// spn1.setSelection(spinner_id);
ArrayAdapter spdrv = new ArrayAdapter(this, R.layout.spin_drop, drive);
d.setAdapter(spdrv);
t1.setVisibility(View.GONE);
mylist = new ArrayList<HashMap<String, String>>();
pos = new ArrayList<String>();
Bundle bundle = getIntent().getExtras();
stuff = bundle.getString("stuff");
if (stuff.contains("null")) {
t1.setVisibility(View.VISIBLE);
t1.setText("No Records Found");
Toast.makeText(getApplicationContext(), "No Records Found!",
Toast.LENGTH_LONG).show();
} else {
load_list(stuff);
}
}
private void startDownload() {
new AppTask().execute(FILENAME);
}
public class AppTask extends AsyncTask<String, Integer, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
}
protected void onPostExecute(String result) {
super.onPostExecute(result);
dialog.dismiss();
String ref = result;
Toast.makeText(getApplicationContext(), "Result= " + ref,
Toast.LENGTH_LONG).show();
Toast.makeText(getApplicationContext(), "POST EXECUTE FLG= " + flg,
Toast.LENGTH_LONG).show();
pos = new ArrayList<String>();
load_list(ref);
/*
* Intent myIntent = new Intent(Slider.this, Slider.class);
*
* Bundle bundle = new Bundle(); // Add your data to bundle
* bundle.putString("stuff", ref); // Add the bundle to the intent
* myIntent.putExtras(bundle); startActivity(myIntent);
*/
}
@Override
protected void onProgressUpdate(Integer... values) {
super.onProgressUpdate(values);
}
@Override
protected String doInBackground(String... params) {
if (flag == 1) {
flag = 0;
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(
"http://1.php");
try {
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(
5);
nameValuePairs.add(new BasicNameValuePair("Qry", query));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
// httpclient.execute(httppost);
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = EntityUtils.toString(entity);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
}
}
if (flag == 2) {
flag = 0;
flg++;
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(
"http://2.php");
try {
flg++;
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(
5);
nameValuePairs.add(new BasicNameValuePair("reg_plc", city));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
httpclient.execute(httppost);
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = EntityUtils.toString(entity);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
}
}
if (flag == 3) {
flag = 0;
flg++;
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(
"http://3.php");
try {
flg++;
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(
5);
nameValuePairs.add(new BasicNameValuePair("reg_plc", city));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
httpclient.execute(httppost);
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = EntityUtils.toString(entity);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
}
}
if (flag == 4) {
if (make.equals("(Select)") || model.equals("(Select)")) {
allcar();
} else {
selectcar();
}
}
return is;
}
public void allcar() {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(
"http://4.php");
try {
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(
3);
nameValuePairs.add(new BasicNameValuePair("city", city));
nameValuePairs.add(new BasicNameValuePair("make", make));
nameValuePairs.add(new BasicNameValuePair("model", model));
nameValuePairs.add(new BasicNameValuePair("range1", range1));
nameValuePairs.add(new BasicNameValuePair("range2", range2));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
// httpclient.execute(httppost);
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = EntityUtils.toString(entity);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
}
}
public void selectcar() {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://5.php");
try {
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(
5);
nameValuePairs.add(new BasicNameValuePair("city", city));
nameValuePairs.add(new BasicNameValuePair("make", make));
nameValuePairs.add(new BasicNameValuePair("model", model));
nameValuePairs.add(new BasicNameValuePair("range1", range1));
nameValuePairs.add(new BasicNameValuePair("range2", range2));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
// httpclient.execute(httppost);
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = EntityUtils.toString(entity);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
}
}
}
@Override
public void onContentChanged() {
super.onContentChanged();
mCloseButton = (Button) findViewById(R.id.button_close);
mOpenButton = (Button) findViewById(R.id.button_open);
mDrawer = (MultiDirectionSlidingDrawer) findViewById(R.id.drawer);
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
}
public void load_list(String lt) {
SimpleAdapter adapter = null;
String[] frm = new String[] {};
int[] too = new int[] {};
SimpleAdapter adapter1 = new SimpleAdapter(this, mylist,
R.layout.text_adaptr, frm, too);
list = getListView();
list.setAdapter(adapter1);
// list.setAdapter(null);
try {
JSONArray jArray = new JSONArray(lt.toString());
for (int i = 0; i < jArray.length(); i++) {
map = new HashMap<String, String>();
JSONObject jObject = jArray.getJSONObject(i);
j_id = jObject.getString(ID);
j_make = jObject.getString(MAKE);
j_model = jObject.getString(MODEL);
j_version = jObject.getString(VERSION);
j_price = jObject.getString(PRICE);
j_reg_plc = jObject.getString(PLACE_REG);
// j_add = jObject.getString(ADDRESS);
data = j_make + "";
map.put("make", data);
data = j_model + "";
map.put("model", data);
data = j_version + "";
map.put("version", data);
data = j_price + "";
map.put("price", data);
data = j_reg_plc + "";
map.put("place", data);
mylist.add(map);
System.out.println("MAP=" + map);
// Toast.makeText(getApplicationContext(), "MAP =" + map,
// Toast.LENGTH_LONG).show();
pos.add(j_id);
}
} catch (JSONException e) {
e.printStackTrace();
}
{
int fl = 0;
fl++;
// list = (ListView) findViewById(R.id.listView1);
String[] from = new String[] { "make", "model", "version", "price",
"place" };
int[] to = new int[] { R.id.text1, R.id.text5, R.id.text3,
R.id.text4, R.id.text2 };
adapter = new SimpleAdapter(this, mylist, R.layout.text_adaptr,
from, to);
list.setAdapter(adapter);
adapter.notifyDataSetChanged();
list.setAdapter(adapter);
// Toast.makeText(getApplicationContext(), "Fl= " + fl,
// Toast.LENGTH_SHORT).show();
}
// ---------------------------------
int[] colors = { 0, 0xff00ffff, 0 }; // red for the example
list.setDivider(new GradientDrawable(Orientation.RIGHT_LEFT, colors));
list.setDividerHeight(4);
list.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Boolean online = isOnline();
if (online == false) {
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(
context);
// set title
alertDialogBuilder.setTitle("Cellular Data is Turned Off!");
// set dialog message
alertDialogBuilder
.setMessage(
"Please turn on cellular data or use Wi-Fi to access data!")
.setCancelable(false)
.setNeutralButton("Settings",
new DialogInterface.OnClickListener() {
public void onClick(
DialogInterface dialog,
int whichButton) {
startActivity(new Intent(
android.provider.Settings.ACTION_WIRELESS_SETTINGS));
}
})
.setPositiveButton("Ok",
new DialogInterface.OnClickListener() {
public void onClick(
DialogInterface dialog, int id) {
dialog.cancel();
}
});
// create alert dialog
AlertDialog alertDialog = alertDialogBuilder.create();
// show it
alertDialog.show();
} else {
String data = pos.get(position) + "";
// Display_Car dc=new Display_Car();
// dc.get_cid(data);
Intent myIntent = new Intent(Slider.this, Buy_View.class);
Bundle bundle = new Bundle();
// Add your data to bundle
bundle.putString("stuff", data);
// Add the bundle to the intent
myIntent.putExtras(bundle);
startActivity(myIntent);
}
}
});
// ---------------------------------
}
@Override
public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
int id = spn1.getSelectedItemPosition();
Editor edit = sid.edit();
edit.putInt("SpnID", id);
edit.commit();
Toast.makeText(getApplicationContext(), "Shared pref=" + sid,
Toast.LENGTH_LONG).show();
if (id == 0) {
flag = 4;
// dialog = ProgressDialog.show(Slider.this, "Loading",
// "Please Wait...");
// startDownload();
Toast.makeText(getApplicationContext(), "ALL", Toast.LENGTH_LONG)
.show();
} else if (id == 1) {
flag = 2;
flg++;
Toast.makeText(getApplicationContext(),
"INSIDE SPINNER FLG= " + flg, Toast.LENGTH_LONG).show();
Toast.makeText(getApplicationContext(), "Dealers Only",
Toast.LENGTH_LONG).show();
dialog = ProgressDialog.show(Slider.this, "Loading",
"Please Wait...");
startDownload();
} else {
flag = 3;
dialog = ProgressDialog.show(Slider.this, "Loading",
"Please Wait...");
startDownload();
Toast.makeText(getApplicationContext(), "Individual Only",
Toast.LENGTH_LONG).show();
}
}
}
你并不需要调用notifyDataSetChanged（）方法，只是用新值重新设定适配器。 –