英文:
Adapter.getView is never called Android Studio
问题
public class MainActivity extends AppCompatActivity {
List<Schedule> races;
startpage_lv_adapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
startPage(2020);
ListView lv = findViewById(R.id.raceList);
lv.setAdapter(adapter);
if (races == null) {
try {
TimeUnit.SECONDS.sleep(3);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
adapter = new startpage_lv_adapter(races, MainActivity.this);
adapter.notifyDataSetChanged();
}
public void startPage(final int year) {
Thread thread = new Thread(new Runnable() {
@Override
public void run() {
Ergast ergast = new Ergast(year, 100, Ergast.DEFAULT_OFFSET);
try {
races = ergast.getSchedules();
} catch (IOException e) {
e.printStackTrace();
}
for (int i = 0; i < races.size(); i++) {
Schedule race = races.get(i);
if (Date.valueOf(race.getDate()).before(Calendar.getInstance().getTime())) {
races.set(i, null);
}
}
races.removeAll(Collections.singletonList(null));
int i = races.size();
if (races.size() == 0) {
startPage(year + 1);
}
}
});
thread.start();
}
}
public class startpage_lv_adapter extends BaseAdapter {
private List<Schedule> races;
private Context context;
public startpage_lv_adapter(List<Schedule> races, Context context) {
this.races = races;
this.context = context;
}
@Override
public int getCount() {
return races.size();
}
@Override
public Object getItem(int position) {
return races.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
convertView = LayoutInflater.from(context).inflate(R.layout.listview_events_detail, parent, false);
String basicURL = "https://restcountries.eu/rest/v2/name/";
String country = races.get(position).getCircuit().getLocation().getCountry();
String extendURL = "?fields=alpha2Code";
try {
HttpResponse<String> httpResponse = Unirest.get(basicURL + country + extendURL)
.asString();
country = httpResponse.getBody().split(":")[1].replace('}', ' ').replace('"', ' ').trim();
} catch (UnirestException e) {
e.printStackTrace();
}
ImageView imageView = convertView.findViewById(R.id.img_countryFlag);
TextView countryText = convertView.findViewById(R.id.text_countryName);
TextView roundText = convertView.findViewById(R.id.text_roundNumber);
basicURL = "https://www.countryflags.io/";
extendURL = "/flat/64.png";
Picasso.get().load(basicURL + country + extendURL);
countryText.setText(races.get(position).getCircuit().getLocation().getCountry());
roundText.setText("Round " + position);
return convertView;
}
}
英文:
Sadly my getView method is never called using a custom adapter, I think it has to do something with the Thread.
I need this Thread to not get an Exception because I cant do Network Activity in the Main Thread obviously. Maybe there is a better option for this.
This is my first Project mit API's so I still need to learn a lot! Thanks for your answers!
public class MainActivity extends AppCompatActivity {
List<Schedule> races;
startpage_lv_adapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
startPage(2020);
ListView lv = findViewById(R.id.raceList);
lv.setAdapter(adapter);
if(races == null){
try {
TimeUnit.SECONDS.sleep(3);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
adapter = new startpage_lv_adapter(races, MainActivity.this);
adapter.notifyDataSetChanged();
}
public void startPage(final int year) {
Thread thread = new Thread(new Runnable() {
@Override
public void run() {
Ergast ergast = new Ergast(year, 100, Ergast.DEFAULT_OFFSET);
try {
races = ergast.getSchedules();
} catch (IOException e) {
e.printStackTrace();
}
for (int i = 0; i < races.size(); i++) {
Schedule race = races.get(i);
if (Date.valueOf(race.getDate()).before(Calendar.getInstance().getTime())) {
races.set(i, null);
}
}
races.removeAll(Collections.singletonList(null));
int i = races.size();
if (races.size() == 0) {
startPage(year+1);
}
}
});
thread.start();
}
}
public class startpage_lv_adapter extends BaseAdapter {
private List<Schedule> races;
private Context context;
public startpage_lv_adapter(List<Schedule> races, Context context) {
this.races = races;
this.context = context;
}
@Override
public int getCount() {
return races.size();
}
@Override
public Object getItem(int position) {
return races.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
convertView = LayoutInflater.from(context).inflate(R.layout.listview_events_detail, parent, false);
String basicURL = "https://restcountries.eu/rest/v2/name/";
String country = races.get(position).getCircuit().getLocation().getCountry();
String extendURL = "?fields=alpha2Code";
try {
HttpResponse<String> httpResponse = Unirest.get(basicURL+country+extendURL)
.asString();
country = httpResponse.getBody().split(":")[1].replace('}', ' ').replace('"', ' ').trim();
} catch (UnirestException e) {
e.printStackTrace();
}
ImageView imageView = convertView.findViewById(R.id.img_countryFlag);
TextView countryText = convertView.findViewById(R.id.text_countryName);
TextView roundText = convertView.findViewById(R.id.text_roundNumber);
basicURL = "https://www.countryflags.io/";
extendURL = "/flat/64.png";
Picasso.get().load(basicURL+country+extendURL);
countryText.setText(races.get(position).getCircuit().getLocation().getCountry());
roundText.setText("Round "+ position);
return convertView;
}
}
答案1
得分: 0
你必须在初始化适配器后（将初始值设置给它），而不是之前，所以将这行 lv.setAdapter(adapter); 移动到 adapter = new startpage_lv_adapter(races, MainActivity.this); 之后，我想知道你的应用怎么没有崩溃 
adapter = new startpage_lv_adapter(races, MainActivity.this);
lv.setAdapter(adapter);
英文:
You have to set adapter after initializing it (set initial value to it) not before, so move this line lv.setAdapter(adapter); after adapter = new startpage_lv_adapter(races, MainActivity.this); , I wonder how your app doesn't crash
adapter = new startpage_lv_adapter(races, MainActivity.this);
lv.setAdapter(adapter);
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