小部件未显示 JSON 结果答案

【问题标题】：Widget not showing JSON result小部件未显示 JSON 结果
【发布时间】：2020-01-26 22:18:11
【问题描述】：

我正在创建一个小部件，它应该从提供 JSON 服务的网站获取天气信息并显示它。这是代码

小部件：

public class MainActivity extends AppWidgetProvider {



public static void onUpdate(Context context, AppWidgetManager appWidgetManager,int appWidgetIds) {
    String resultadoObtido = "";

    SharedPreferences c = PreferenceManager.getDefaultSharedPreferences(context);
    String cidade = c.getString("cidade", "Coimbra");

    try {
        Dados d = new Dados(cidade);
        resultadoObtido = d.execute().get();

    }catch (InterruptedException e){
        e.printStackTrace();                    
    }               
    catch (ExecutionException e) {
        // TODO: handle exception
        e.printStackTrace();
    }
    String string = resultadoObtido;

    String[] parts = string.split("/");
    String part1 = parts[0];
    String part2 = parts[1];
    String part3 = parts[2];
    String part4 = parts[3];
    String part5 = parts[4];

    float atual =Float.parseFloat(part1);
    float minima =Float.parseFloat(part2);
    float maxima = Float.parseFloat(part3);

    float atualC = (float) (atual-273.15);
    float minimaC  = (float) (minima-273.15);
    float maximaC = (float) (maxima-273.15);

    String result1 =String.format("%.1f", atualC);
    String result2 =String.format("%.1f", minimaC);
    String result3 =String.format("%.1f", maximaC);

    RemoteViews view =new RemoteViews(context.getPackageName(),R.layout.activity_main);

    view.setTextViewText(R.id.cidade,""+part4);
    view.setTextViewText(R.id.temp,""+result1+"ºC");
    view.setTextViewText(R.id.temp_max,""+result2+"ºC");
    view.setTextViewText(R.id.temp_min,""+result3+"ºC");




}

}

获得服务的类dados：公共类 Dados 扩展 AsyncTask {

String Resultado = "";
public String s,city;
public Dados(String cidade){
    city=cidade;        
}

@Override
protected String doInBackground(String... params) {
    // TODO Auto-generated method stub
    try {
        s = getJson("http://api.openweathermap.org/data/2.5/weather?q="+city+",pt");
        JSONObject jobj = new JSONObject(s);
        JSONObject detalhe= jobj.getJSONObject("main");
        JSONArray weather = jobj.getJSONArray("weather");
        Resultado = detalhe.getString("temp")+"/"+detalhe.getString("temp_min")+"/"
        +detalhe.getString("temp_max")+"/"+jobj.getString("name")
        +"/"+weather.getJSONObject(0).getString("main");
    } catch (Exception e) {
        // TODO: handle exception
        e.printStackTrace();
    }


    return Resultado;
}

public String getJson (String url) throws ClientProtocolException, IOException{

    StringBuilder build = new StringBuilder();
    HttpClient client = new DefaultHttpClient();
    HttpGet httpGet = new HttpGet(url);
    HttpResponse response = client.execute(httpGet);
    HttpEntity entity = response.getEntity();
    InputStream content = entity.getContent();
    BufferedReader reader =  new BufferedReader(new InputStreamReader(content));
    String con;
    while ((con=reader.readLine())!= null){
        build.append(con);
    }
    return build.toString();

}

}

配置：

public class Config extends Activity{

private int myWidgetId;
Context context;

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setResult(RESULT_CANCELED);
    setContentView(R.layout.config);

    final EditText cidade = (EditText) findViewById(R.id.editText1);
    context=Config.this;
    Intent intent = getIntent();
    Bundle extras = intent.getExtras();
    if (extras!=null) {
        myWidgetId = extras.getInt(AppWidgetManager.EXTRA_APPWIDGET_ID, 
                AppWidgetManager.INVALID_APPWIDGET_ID);
    }
    if(myWidgetId == AppWidgetManager.INVALID_APPWIDGET_ID ){
        finish();
    }
    Button bt1 = (Button) findViewById(R.id.button1);
    bt1.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View arg0) {
            String city = cidade.getText().toString();
            SharedPreferences.Editor editor = getPreferences(MODE_PRIVATE).edit();
            editor.putString("Cidade", city);
            editor.commit();

            AppWidgetManager appWMan= AppWidgetManager.getInstance(context);
            MainActivity.onUpdate(context, appWMan,myWidgetId);
            Intent resultvalue = getIntent();
            resultvalue.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID,myWidgetId);
            setResult(RESULT_OK,resultvalue);
            finish();


        }
    });

}

}

我没有收到任何错误，但小部件仅显示带有默认文本的 textView。谁能弄清楚这正在发生？

【问题讨论】：

标签： android json android-widget

【解决方案1】：

您只需在 asynctask 中添加 onPostExecute 方法即可将数据设置为 TextView 并在 MainActivity 类中编写您的 asynctask 类。

所以你的 MainActivity 类将如下所示

    public class MainActivity extends AppWidgetProvider {
       Context context;


       public static void onUpdate(Context context, AppWidgetManager appWidgetManager,int appWidgetIds) {
         this.context=context;

         SharedPreferences c = PreferenceManager.getDefaultSharedPreferences(context);
         String cidade = c.getString("cidade", "Coimbra");

         try {
            new Dados(cidade).execute();
         } catch (InterruptedException e){
            e.printStackTrace();                    
         } catch (ExecutionException e) {           
            e.printStackTrace();
         }
      }

      public class Dados extends AsyncTask<Void,Void,String>{
         public String s,city;
         public Dados(String cidade){
            city=cidade;        
         }

         @Override
         protected String doInBackground(Void... params) {          
           String Resultado = "";

           try {
               s = getJson("http://api.openweathermap.org/data/2.5/weather?q="+city+",pt");
               JSONObject jobj = new JSONObject(s);
               JSONObject detalhe= jobj.getJSONObject("main");
               JSONArray weather = jobj.getJSONArray("weather");
               Resultado = detalhe.getString("temp")+"/"+detalhe.getString("temp_min")+"/"
            +detalhe.getString("temp_max")+"/"+jobj.getString("name")
            +"/"+weather.getJSONObject(0).getString("main");
           } catch (Exception e) {
               e.printStackTrace();
           }

           return Resultado;
    }

    @Override
    protected void onPostExecute(String result) {
        super.onPostExecute(result);        

        if(result!=null && !result.trim().isEmpty()){

            String[] parts = result.split("/");
            String part1 = parts[0];
            String part2 = parts[1];
            String part3 = parts[2];
            String part4 = parts[3];
            String part5 = parts[4];

            float atual =Float.parseFloat(part1);
            float minima =Float.parseFloat(part2);
            float maxima = Float.parseFloat(part3);

            float atualC = (float) (atual-273.15);
            float minimaC  = (float) (minima-273.15);
            float maximaC = (float) (maxima-273.15);

            String result1 =String.format("%.1f", atualC);
            String result2 =String.format("%.1f", minimaC);
            String result3 =String.format("%.1f", maximaC);

            RemoteViews view =new RemoteViews(context.getPackageName(),R.layout.activity_main);

            view.setTextViewText(R.id.cidade,""+part4);
            view.setTextViewText(R.id.temp,""+result1+"ºC");
            view.setTextViewText(R.id.temp_max,""+result2+"ºC");
            view.setTextViewText(R.id.temp_min,""+result3+"ºC");
        }
    }

    public String getJson (String url) throws ClientProtocolException, IOException{

        StringBuilder build = new StringBuilder();
        HttpClient client = new DefaultHttpClient();
        HttpGet httpGet = new HttpGet(url);
        HttpResponse response = client.execute(httpGet);
        HttpEntity entity = response.getEntity();
        InputStream content = entity.getContent();
        BufferedReader reader =  new BufferedReader(new InputStreamReader(content));
        String con;
        while ((con=reader.readLine())!= null){
            build.append(con);
        }
        return build.toString();

    }
}

}

【讨论】：

这就是我告诉你的。在 MainActivity 类中编写你的异步任务。

【解决方案2】：

我设法通过移动这部分代码来解决问题

try {
    Dados d = new Dados(cidade);
    resultadoObtido = d.execute().get();

}catch (InterruptedException e){
    e.printStackTrace();                    
}               
catch (ExecutionException e) {
    // TODO: handle exception
    e.printStackTrace();
}
String string = resultadoObtido;

String[] parts = string.split("/");
String part1 = parts[0];
String part2 = parts[1];
String part3 = parts[2];
String part4 = parts[3];
String part5 = parts[4];

float atual =Float.parseFloat(part1);
float minima =Float.parseFloat(part2);
float maxima = Float.parseFloat(part3);

float atualC = (float) (atual-273.15);
float minimaC  = (float) (minima-273.15);
float maximaC = (float) (maxima-273.15);

String result1 =String.format("%.1f", atualC);
String result2 =String.format("%.1f", minimaC);
String result3 =String.format("%.1f", maximaC);

到扩展服务的类，然后在小部件上调用服务。

【讨论】：