我正在使用OkHttp3作为网络库,并使用Node-Mongo作为后端服务。我正在列表视图中从服务器中获取数据。每当我的应用程序第一次启动时,它将从服务器中加载我要缓存的数据数据,以便在应用再次启动时无需花费时间在应用中显示数据。 我不知道如何实现缓存功能。 这是我的代码:
MainActivity.java
public class Activity2 extends AppCompatActivity {
ListView listView;
List<Data> places;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_2);
listView = findViewById(R.id.listView);
places = new ArrayList<>();
final ProgressDialog prg = new ProgressDialog(MainActivity.this);
prg.setMessage("Loading...");
prg.show();
Log.d("OnCreate","Oncreate started");
OkHttpClient client = new OkHttpClient();
Request request = new
Request.Builder().url("https://tiffino.herokuapp.com/test").build();
client.newCall(request).enqueue(new Callback() {
@Override
public void onFailure(Call call, final IOException e) {
prg.dismiss();
runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(getApplicationContext(),""+e.getMessage(),
Toast.LENGTH_SHORT).show();
}
});
}
@Override
public void onResponse(Call call, final Response response) throws
IOException {
prg.dismiss();
runOnUiThread(new Runnable() {
@Override
public void run() {
try {
JSONArray arr = new
JSONArray(response.body().string());
for(int i = 0;i < arr.length();i++){
JSONObject obj = arr.getJSONObject(i);
String str1 = obj.getString("Name");
Data data = new Data(str1);
places.add(data);
}
PlacesAdapter adapter= new PlacesAdapter(places,getApplicationContext());
listView.setAdapter(adapter);
} catch (JSONException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
});
}
});
}
}
PlacesAdapter.java
public class PlacesAdapter extends ArrayAdapter<Data> {
private List<Data> places;
private Context ctx;
public PlacesAdapter( List<Data> places, Context ctx) {
super(ctx,R.layout.places_row,places);
this.places = places;
this.ctx = ctx;
}
@NonNull
@Override
public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
LayoutInflater inflater = LayoutInflater.from(ctx);
View listView = inflater.inflate(R.layout.places_row,null,true);
TextView txt = listView.findViewById(R.id.txt);
Data data = places.get(position);
txt.setText(data.getPlace());
return listView;
}
}
请让我知道如何实现这一目标。
谢谢