我目前正在显示JSON查询中的项目列表，但想实现一种通过菜单对结果进行排序的方法。我尝试使用的两个排序参数是按受欢迎程度排序和按平均评分排序。我试图通过更改从中查询结果的URL来执行此操作，因为api查询具有用于根据受欢迎程度和平均评分显示JSON数据的参数。当我单击菜单项时，我尝试执行此购买，活动未填充新结果。 URL更改了，但是新的结果没有显示。任何帮助或提示将不胜感激
主要活动：
package com.davejones.spritetest;
import com.badlogic.gdx.ApplicationAdapter;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.graphics.OrthographicCamera;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.Sprite;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import com.badlogic.gdx.math.Vector2;
import com.badlogic.gdx.physics.box2d.Body;
import com.badlogic.gdx.physics.box2d.BodyDef;
import com.badlogic.gdx.physics.box2d.Box2DDebugRenderer;
import com.badlogic.gdx.physics.box2d.Fixture;
import com.badlogic.gdx.physics.box2d.FixtureDef;
import com.badlogic.gdx.physics.box2d.PolygonShape;
import com.badlogic.gdx.physics.box2d.World;
public class SpriteTest extends ApplicationAdapter {
private SpriteBatch batch;
private World world;
private BodyDef bodyDef;
private Body body;
private Texture texture;
private Sprite sprite;
private OrthographicCamera camera;
private Box2DDebugRenderer debugRenderer;
@Override
public void create () {
debugRenderer = new Box2DDebugRenderer();
debugRenderer.setDrawBodies(false);
camera = new OrthographicCamera();
batch = new SpriteBatch();
texture = new Texture("badlogic.jpg");
sprite = new Sprite(texture);
sprite.setPosition(Gdx.graphics.getWidth() / 2 - sprite.getWidth() / 2, Gdx.graphics.getHeight() / 2);
world = new World(new Vector2(0, -10), true);
bodyDef = new BodyDef();
bodyDef.type = BodyDef.BodyType.DynamicBody;
bodyDef.position.set(sprite.getX(), sprite.getY());
body = world.createBody(bodyDef);
PolygonShape shape = new PolygonShape();
shape.setAsBox(sprite.getWidth()/2, sprite.getHeight()/2);
FixtureDef fixtureDef = new FixtureDef();
fixtureDef.shape = shape;
fixtureDef.density = 1f;
Fixture fixture = body.createFixture(fixtureDef);
shape.dispose();
}
@Override
public void resize(int width, int height) {
super.resize(width, height);
float cameraWidth = Gdx.graphics.getWidth();
float cameraHeight = Gdx.graphics.getHeight();
camera.setToOrtho(false, cameraWidth, cameraHeight);
camera.position.set(Gdx.graphics.getWidth() / 2 - sprite.getWidth() / 2, Gdx.graphics.getHeight() / 2 - sprite.getHeight() / 2, 0);
}
@Override
public void render () {
world.step(Gdx.graphics.getDeltaTime(), 8, 3);
sprite.setPosition(body.getPosition().x, body.getPosition().y);
Gdx.gl.glClearColor(0, 0, 0, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
batch.begin();
batch.draw(sprite, sprite.getX(), sprite.getY());
batch.end();
System.out.println(body.getLinearVelocity().y);
camera.update();
debugRenderer.render(world, camera.combined);
}
@Override
public void dispose () {
batch.dispose();
texture.dispose();
world.dispose();
debugRenderer.dispose();
}
};
NetworkUtils
public class MainActivity extends AppCompatActivity {
public static final String TAG = "MainActivity";
//Declare some of the objects we are using.
String SEARCH_TERM = "popularity.desc";
private RecyclerView mRecyclerView;
//GridLayoutManage will allow us to load our items in a grid.
private GridLayoutManager gridLayoutManager;
//Custoj Adapter lets us bind out data from the web server with our recylerview
private MovieAdapter mMovieAdapter;
//Need a list to store the data from the server.
private List<Movie> movieData;
/*
API KEY
https://api.themoviedb.org/3/movie/550?api_key=1f5029b7d824dee72f4d4a156dac90ed
*/
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Reference the RecyclerView
mRecyclerView = findViewById(R.id.recycler_view);
//Reference the list. This needs to be done before setting the adapter to the recycler
//view or the app will think there is an empty list.
movieData = new ArrayList<>();
//To update the list with items, we create a new method to do that.
loadMovieData();
//Create a new grid layout manager in order to display data to a grid.
gridLayoutManager = new GridLayoutManager(this, 3);
mRecyclerView.setLayoutManager(gridLayoutManager);
//Bind the data we receive from the web server to the recyclerview itself.
mMovieAdapter = new MovieAdapter(this, movieData);
//Apply the adapter to the recyclerview.
mRecyclerView.setAdapter(mMovieAdapter);
}
//Tell the new method to get the dat abased on the search term within the url.
private void loadMovieData() {
new FetchMovieTask().execute(SEARCH_TERM);
}
//Inflate the menu
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.main_menu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.sort_by_most_popular:
SEARCH_TERM = "popularity.desc";
loadMovieData();
mMovieAdapter.notifyDataSetChanged();
return true;
case R.id.sort_by_highest_rated:
SEARCH_TERM = "popularity.asc";
loadMovieData();
mMovieAdapter.notifyDataSetChanged();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
//We need to use an AsyncTask to perform the request to get the data. The first argument
//we use a String because this will allow us to pass the url.
public class FetchMovieTask extends AsyncTask<String, Void, Void> {
@Override
protected Void doInBackground(String... strings) {
final String MOVIES_RESULTS = "results";
final String MOVIES_POSTER_IMAGE = "poster_path";
final String MOVIES_TITLE = "title";
final String RELEASE_DATE = "release_date";
final String VOTE_AVERAGE = "vote_average";
final String PLOT = "overview";
//Create the network request to download the JSON data from the url database.
URL moviesUrl = NetworkUtils.buildUrl(SEARCH_TERM);
try {
//The response we get is in the form of JSON.
String jsonMoviesResponse = NetworkUtils.getReponseFromHttpUrl(moviesUrl);
//A new JSON object created from the JSON response.
JSONObject moviesJson = new JSONObject(jsonMoviesResponse);
//Read the movie results array from the JSON object.
JSONArray moviesArray = moviesJson.getJSONArray(MOVIES_RESULTS);
//A loop is created to read the array and add the data we need to a list.
for (int i = 0; i < moviesArray.length(); i++) {
String moviePoster;
String movieTitle;
String movieReleaseDate;
String voteAverage;
String plot;
JSONObject movie = moviesArray.getJSONObject(i);
moviePoster = ("http://image.tmdb.org/t/p/w185/" + movie.getString(MOVIES_POSTER_IMAGE));
movieTitle = movie.getString(MOVIES_TITLE);
movieReleaseDate = movie.getString(RELEASE_DATE);
voteAverage = movie.getString(VOTE_AVERAGE);
plot = movie.getString(PLOT);
Movie data = new Movie(movieTitle, movieReleaseDate, moviePoster, voteAverage, plot);
//Add the data items to our movieData list.
movieData.add(data);
}
} catch (JSONException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
//This is called when the network request is done. We use this method to tell our
//custom adapter that there is a change in the data list so that it can load new cardview
//widgets in the list.
@Override
protected void onPostExecute(Void aVoid) {
mMovieAdapter.notifyDataSetChanged();
}
}
公共类NetworkUtils {
//Build the class which will build the URL and talk to the database.
}
答案 0 :(得分：1)
如果我是对的，那么您在添加新电影之前并没有清洗电影阵列，因此新获取的项目必须在列表的尾部。
在AsyncTask的onPreExecute()上，您应该调用movieData.clear(); mMovieAdapter.notifyDataSetChanged();。
希望有帮助！