Android:来自MySQL的ListView只显示最后一个元素
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我正在尝试从MySql数据库中检索数据并将其放在ListView上,一切正常,我甚至将这些数据放入textview(动态),它工作正常.但是当我使用ListView时,只显示了最后一个元素,我认为这意味着每个新元素都会被旧元素覆盖,对吧?
我该怎么做才能解决这个问题?这是我的代码告诉我哪里错了?
public class MakeAppointementActivity extends AppCompatActivity {
public List<AvailabilityList> customList;
public ListView lv;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_make_appointement);
lv=(ListView)findViewById(R.id.listView);
Intent intent=getIntent();
new RetrieveTask().execute();
}
private class RetrieveTask extends AsyncTask<Void, Void, String> {
@Override
protected String doInBackground(Void... params) {
String strUrl = "availableAppointments1.php";
URL url;
StringBuffer sb = new StringBuffer();
try {
url = new URL(strUrl);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.connect();
InputStream iStream = connection.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(iStream));
String line;
while( (line = reader.readLine()) != null){
sb.append(line);
}
reader.close();
iStream.close();
} catch (IOException e) {
e.printStackTrace();
}
return sb.toString();
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
new ParserTask().execute(result);
}
}
// Background thread to parse the JSON data retrieved from MySQL server
private class ParserTask extends AsyncTask<String, Void, List<HashMap<String, String>>> {
@Override
protected List<HashMap<String, String>> doInBackground(String... params) {
AppointementJSONParser appointementParser = new AppointementJSONParser();
JSONObject json = null;
try {
json = new JSONObject(params[0]);
} catch (JSONException e) {
e.printStackTrace();
}
return appointementParser.parse(json);
}
@Override
protected void onPostExecute(List<HashMap<String, String>> result) {
customList=new ArrayList<>(); / move it to here
for (int i = 0; i < result.size(); i++) {
HashMap<String, String> appointement = result.get(i);
String fromT = appointement.get("fromT");
String toT = appointement.get("toT");
String date = appointement.get("date");
addAvailableAppoint(fromT,toT,date);
}
updateListView(); // update listview when you add all data to arraylist
}
}
private void addAvailableAppoint(final String fromT, final String toT, final String date) {
customList.add(new AvailabilityList(fromT));
}
// split new function for update listview
private updateListView(){
ArrayAdapter adapter=new DoctorAvailabilityAdapter(MakeAppointementActivity.this,R.layout.list_items,customList);
adapter.notifyDataSetChanged();
lv.setAdapter(adapter);
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Intent intent = new Intent(MakeAppointementActivity.this, AppointementActivity.class);
intent.putExtra("fromT", fromT);
intent.putExtra("toT", toT);
intent.putExtra("date", date);
startActivity(intent);
}
});
}
}
解决方法:
试试这个代码
.....// your above code
@Override
protected void onPostExecute(List<HashMap<String, String>> result) {
customList=new ArrayList<>(); / move it to here
for (int i = 0; i < result.size(); i++) {
HashMap<String, String> appointement = result.get(i);
String fromT = appointement.get("fromT");
String toT = appointement.get("toT");
String date = appointement.get("date");
addAvailableAppoint(fromT,toT,date);
}
updateListView(); // update listview when you add all data to arraylist
}
}
private void addAvailableAppoint(final String fromT, final String toT, final String date) {
customList.add(new AvailabilityList(fromT));
}
// split new function for update listview
private updateListView(){
ArrayAdapter adapter=new DoctorAvailabilityAdapter(MakeAppointementActivity.this,R.layout.list_items,customList);
adapter.notifyDataSetChanged();
lv.setAdapter(adapter);
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Intent intent = new Intent(MakeAppointementActivity.this, AppointementActivity.class);
// intent.putExtra("fromT", fromT); // change it to
intent.putExtra("fromT", customList.get(position).getFromT());
intent.putExtra("toT", toT);
intent.putExtra("date", date);
startActivity(intent);
}
});
}
}
希望这有帮助
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