Question

我创建了一个应用程序，用于从URL收听webradio，并从JSON URL显示艺术家的名字/歌曲。它正在工作，但我想在新歌开始时更改这些名称。为此，我想我需要刷新JSON URL中的数据，但我不知道如何。

我尝试了很多教程但是找不到解决方法。谢谢。

主要活动：

 public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        btn_play = (Button) findViewById(R.id.buttonplay);
        mediaPlayer = new MediaPlayer();
        mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
        progressDialog = new ProgressDialog(this);

        if (initialStage) {
            new Player().execute("http://www.radioking.com/play/tft-radio");
            btn_play.setBackgroundResource(R.drawable.pause);
        } else {
            if (!mediaPlayer.isPlaying())
                mediaPlayer.start();
        }

        btn_play.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (!playPause) {
                    btn_play.setBackgroundResource(R.drawable.pause);
                            mediaPlayer.start();
                    playPause = true;

                } else {
                    btn_play.setBackgroundResource(R.drawable.playbutton);

                    if (mediaPlayer.isPlaying()) {
                        mediaPlayer.pause();
                    }

                    playPause = false;
                }
            }
        });


        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.setDrawerListener(toggle);
        toggle.syncState();

        NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);
    }

    @Override
    protected void onPause() {
        super.onPause();

        if (mediaPlayer != null) {
            mediaPlayer.reset();
            mediaPlayer.release();
            mediaPlayer = null;
        }
    }

    class Player extends AsyncTask<String, Void, Boolean> {
        @Override
        protected Boolean doInBackground(String... strings) {
            Boolean prepared = false;

            try {
                mediaPlayer.setDataSource(strings[0]);
                mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
                    @Override
                    public void onCompletion(MediaPlayer mediaPlayer) {
                        initialStage = true;
                        playPause = false;
                        btn_play.setText("Lecture");
                        mediaPlayer.stop();
                        mediaPlayer.reset();
RestOperation test = new RestOperation();
            String test2 = null;
            try {

                test2 = test.execute(restURL).get().toString();
                Log.i("result", test2);
            } catch (InterruptedException e) {
                e.printStackTrace();
            } catch (ExecutionException e) {
                e.printStackTrace();
            }

            splitArray = test2.split(",");
            artiste = (splitArray[0]).replace("{\"artist\":\"","");
            finalArtiste = artiste.replace("\"","");
            titre = (splitArray[1]).replace("\"title\":\"","");
            finalTitre = titre.replace("\"","");
            image = (splitArray[3]).replace("\"cover\":\"","");
            finalImage = image.replace("\"","");
            finalImage2 = finalImage.replace("\\","");

            Log.i("splitage",finalImage2);


            tvTitre = (TextView) findViewById(R.id.tv_titre);
            tvArtiste = (TextView) findViewById(R.id.tv_artiste);

            tvTitre.setText("Titre : " + finalTitre);
            tvArtiste.setText("Artiste : " + finalArtiste);

            welcome = (ImageView) findViewById(R.id.imgArtiste);

    if(finalImage2.contains("http") ){
        Picasso.with(this).load(finalImage2).into(welcome);
    }else {
        welcome.setBackgroundResource(R.drawable.logokol);
    }
                        }
                    });

                mediaPlayer.prepare();
                prepared = true;

            } catch (Exception e) {
                Log.e("MyAudioStreamingApp", e.getMessage());
                prepared = false;
            }

            return prepared;
        }

        @Override
        protected void onPostExecute(Boolean aBoolean) {
            super.onPostExecute(aBoolean);

            if (progressDialog.isShowing()) {
                progressDialog.cancel();
            }

            mediaPlayer.start();
            initialStage = false;
        }

        @Override
        protected void onPreExecute() {
            super.onPreExecute();

            progressDialog.setMessage("Chargement...");
            progressDialog.show();
        }
    }

    @Override
    public void onBackPressed() {
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @SuppressWarnings("StatementWithEmptyBody")

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }

    private class RestOperation extends AsyncTask<String, Void, String> {

        String content;
        String error;
        ProgressDialog progressDialog = new ProgressDialog(MainActivity.this);
        String data = "";



        @Override
        protected void onPreExecute() {
            super.onPreExecute();

            progressDialog.setTitle("Please wait ...");
//            progressDialog.show();

        }

        @Override
        protected String doInBackground(String... params) {
            BufferedReader br = null;

            URL url;
            try {
                url = new URL(params[0]);

                URLConnection connection = url.openConnection();
                connection.setDoOutput(true);

                OutputStreamWriter outputStreamWr = new OutputStreamWriter(connection.getOutputStream());
                outputStreamWr.write(data);
                outputStreamWr.flush();

                br = new BufferedReader(new InputStreamReader(connection.getInputStream()));
                StringBuilder sb = new StringBuilder();
                String line = null;

                while((line = br.readLine())!=null) {
                    sb.append(line);
                    sb.append(System.getProperty("line.separator"));
                }

                content = sb.toString();

            } catch (MalformedURLException e) {
                error = e.getMessage();
                e.printStackTrace();
            } catch (IOException e) {
                error = e.getMessage();
                e.printStackTrace();
            } finally {
                try {
                    br.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            return content;
        }

        }

    }

Answer 1

您必须将网络服务电话添加到CompletionListener

 mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
     @Override
     public void onCompletion(MediaPlayer mp) {
         test2 = test.execute(restURL).get().toString();
     }
});

Answer 2

test2 = test.execute(restURL).get().toString();

不是您应该执行异步任务的方式（AsyncTask根据定义为asynchrone）。

您应该在onPostExecute（..）方法中使用您的结果。

查看https://developer.android.com/reference/android/os/AsyncTask.html

如何从android中的json url刷新数据？

2 个答案: