我一直在努力学习loadash以及如何使用一些更高级的技巧正确地提取我想要的数据。单个对象和查找非常简单，但是我试图通过groupId拉出所有数组记录，如果该groupId存在于另一个不相同的对象中。
例如： 对象的通用JSON示例，每个都是记录数组。
var results = [];
_.forEach(Groups, function(g) {
var found _.find(Options, g, function(option, group) {
return option.groupId === group.groupId;
})
results.push(found);
});
我遇到的问题是只有在loadash中的groups数组中存在groupId时才会提取所有选项。
我尝试了一些像
这样的东西public class ListViewActivity extends Activity implements LocationListener {
// Log tag
private static final String TAG = ListViewActivity.class.getSimpleName();
// change here url of server api
// private static final String url = "https://comida-95724.herokuapp.com/api/v1/restaurants?per_page=5&km=1&location=true&lat=19.0558306414&long=72.8339840099";
private ProgressDialog pDialog;
private static String url;
private List<Movie> movieList = new ArrayList<Movie>();
private ListView listView;
private CustomListAdapter adapter;
/**
* ATTENTION: This was auto-generated to implement the App Indexing API.
* See https://g.co/AppIndexing/AndroidStudio for more information.
*/
private GoogleApiClient client;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_listview);
LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
client = new GoogleApiClient.Builder(this).addApi(AppIndex.API).build();
//update coordinates every 30 seconds
if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 30 * 1000, 1, this);
listView = (ListView) findViewById(R.id.list);
adapter = new CustomListAdapter(this, movieList);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Movie movie = movieList.get(position);
Intent intent = new Intent(ListViewActivity.this, SecondActivity.class);
intent.putExtra("name", movie.getName());
intent.putExtra("average_ratings", movie.getAverage_ratings());
intent.putExtra("full_address", movie.getAddress());
intent.putExtra("image_url", movie.getThumbnailUrl());
intent.putExtra("cuisine", movie.getCuisine());
intent.putExtra("cost", movie.getCost());
startActivity(intent);
}
});
listView.setAdapter(adapter);
pDialog = new ProgressDialog(this);
// Showing progress dialog before making http request
pDialog.setMessage("Please Keep patience.Its loading...");
pDialog.show();
}
private void loadJson(double latitude, double longitude) {
adapter = new CustomListAdapter(this, movieList);
listView.setAdapter(adapter);
adapter.clear();
url = "https://comida-95724.herokuapp.com/api/v1/restaurants?per_page=5&km=1&location=true&lat="+latitude+"&long="+longitude;
// Creating volley request obj
JsonObjectRequest movieReq = new JsonObjectRequest(Request.Method.GET,
url, null, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
Log.d(TAG, response.toString());
JSONArray
restaurantsJSONArray = null;
try {
restaurantsJSONArray = response.getJSONArray("restaurants");
} catch (JSONException e) {
e.printStackTrace();
}
hidePDialog();
// Parsing json
for (int i = 0; i < restaurantsJSONArray.length(); i++) {
try {
JSONObject obj = restaurantsJSONArray.getJSONObject(i);
Movie movie = new Movie();
//movie.setTitle(obj.getString("title"));
movie.setName(obj.getString("name"));
//movie.setThumbnailUrl(obj.getString("image"));
movie.setThumbnailUrl(obj.getString("org_image_url"));
movie.setAverage_ratings(obj.getString("average_ratings"));
movie.setCuisine(obj.getString("cuisine"));
movie.setAddress(obj.getJSONObject("address").getString("area"));
// movie.setAddress(obj.getJSONObject("address").getString("full_address"));
movie.setCost(obj.getString("cost"));
movie.setDistance(obj.getDouble("distance"));
JSONArray textJSONArray = obj.getJSONArray("restaurant_offers");
for (int j = 0; j < textJSONArray.length(); j++) {
JSONObject txtobj = textJSONArray.getJSONObject(j);
//obj.getJSONArray("restaurant_offers").getJSONObject(0).getString("text");
//movie.settext(obj.getJSONArray("restaurant_offers").getJSONObject(j).getString("text"));
movie.settext(txtobj.getString("text"));
}
// movie.settext(obj.getString("text"));
movieList.add(movie);
} catch (JSONException e) {
e.printStackTrace();
}
}
adapter.notifyDataSetChanged();
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d(TAG, "Error: " + error.getMessage());
hidePDialog();
}
});
AppController.getInstance().addToRequestQueue(movieReq);
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
//client = new GoogleApiClient.Builder(this).addApi(AppIndex.API).build();
// client = new GoogleApiClient.Builder(this).addConnectionCallbacks((GoogleApiClient.ConnectionCallbacks) this).addOnConnectionFailedListener((GoogleApiClient.OnConnectionFailedListener) this).addApi(AppIndex.API).build();
}
@Override
public void onDestroy() {
super.onDestroy();
hidePDialog();
}
private void hidePDialog() {
if (pDialog != null) {
pDialog.dismiss();
pDialog = null;
}
}
@Override
public void onStart() {
super.onStart();
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
client.connect();
Action viewAction = Action.newAction(
Action.TYPE_VIEW, // TODO: choose an action type.
"ListView Page", // TODO: Define a title for the content shown.
// TODO: If you have web page content that matches this app activity's content,
// make sure this auto-generated web page URL is correct.
// Otherwise, set the URL to null.
Uri.parse("http://host/path"),
// TODO: Make sure this auto-generated app URL is correct.
Uri.parse("android-app://com.comida/http/host/path")
);
AppIndex.AppIndexApi.start(client, viewAction);
}
@Override
public void onStop() {
super.onStop();
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
Action viewAction = Action.newAction(
Action.TYPE_VIEW, // TODO: choose an action type.
"ListView Page", // TODO: Define a title for the content shown.
// TODO: If you have web page content that matches this app activity's content,
// make sure this auto-generated web page URL is correct.
// Otherwise, set the URL to null.
Uri.parse("http://host/path"),
// TODO: Make sure this auto-generated app URL is correct.
Uri.parse("android-app://com.comida/http/host/path")
);
AppIndex.AppIndexApi.end(client, viewAction);
client.disconnect();
}
@Override
public void onLocationChanged(Location location) {
//whenever location is updated call method that will load JSON
loadJson(location.getLatitude(),location.getLongitude());
Log.d("hello", location.getLatitude() + " " + location.getLongitude());
}
@Override
public void onStatusChanged(String provider, int i, Bundle bundle) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onProviderDisabled(String provider) {
}
}
我没有太多的运气找出最好的方法来过滤这些。
任何言语，如果智慧会受到赞赏，谢谢！
答案 0 :(得分：3)
这样的事情应该有效，
var result = _.filter(Options, function(o) {
return _.filter(Groups, function(g) { return g.groupId == o.groupid; }).length > 0;
});
实际上我认为内部搜索会在find中表现更好，因为它会返回第一场比赛，但不确定
var result = _.filter(Options, function(o) {
return _.find(Groups, { 'groupId': o.groupid });
});
希望这会有所帮助。