我无法在try catch中访问值

时间：2019-05-31 21:08:19

标签： android json try-catch

我有三个要发送给MainActivity的值。 JSONObject json到达时带有正确的值，但是在try catch中未访问此值，即onPostExecute仅执行pDialog.dismiss（）;。

我如何获取onPostExecute以便在内部读取尝试小插曲？

MainActivity 

package ic.eng.br.testejson;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

public class MainActivity extends AppCompatActivity implements Json{

    EditText edtUsuario, edtSenha;
    Button btnLogin;
    TextView textView1, textView2, textView3;

    JSONArray user = null;

    String url = "http://www.ic.eng.br/android/login.php";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        edtUsuario = findViewById(R.id.edtUsuario);
        edtSenha = findViewById(R.id.edtSenha);
        btnLogin = findViewById(R.id.btnLogin);
        textView1 = findViewById(R.id.textView1);
        textView2 = findViewById(R.id.textView2);
        textView3 = findViewById(R.id.textView3);


        final Asyncexecute asyncexecute = new Asyncexecute(this, this);


    btnLogin.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            String usuario = edtUsuario.getText().toString();
            String senha = edtSenha.getText().toString();

            asyncexecute.execute(usuario, senha, url, "");

        }
    });


    }

public void testejson (String Rsenha, String Rprivilegio, String Rperfil) {

            textView1.setText(Rsenha);
            textView2.setText(Rprivilegio);
            textView3.setText(Rperfil);


}

}

异步执行：

package ic.eng.br.testejson;

import android.app.ProgressDialog;
import android.content.Context;
import android.os.AsyncTask;
import android.util.Log;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutionException;

@SuppressWarnings("deprecation")
public class Asyncexecute extends AsyncTask <String, String, JSONObject> {

    private ProgressDialog pDialog;
    private Context context;

    JSONArray user = null;

    String Rsenha, Rprivilegio, Rperfil;

    String usuario, senha, url;

    private static final String TAG_USER = "usuario";

    private Json execinterface;

    static InputStream is = null;
    static JSONObject jObj = null;
    static String json = "";


    public Asyncexecute(Context context,  Json execinterface) {
        this.execinterface = execinterface;
        this.context = context;
    }

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

        pDialog = new ProgressDialog(context);
        pDialog.setMessage("Carregando");
        pDialog.setIndeterminate(false);
        pDialog.setCancelable(true);
        pDialog.show();


    }

    @Override
    protected JSONObject doInBackground(String... params) {
        usuario = params[0];
        senha = params[1];
        url = params[2];

        JSONParser jParser = new JSONParser();
        JSONObject json = jParser.getJSONFromUrl(url);;

        return json;
    }

    @Override
    protected void onPostExecute(JSONObject json) {
        pDialog.dismiss();

        try {
             user = json.getJSONArray("login");
             JSONObject c = user.getJSONObject(0);

            Rsenha = c.getString("senha");
             Rprivilegio = c.getString("privilegio");
             Rperfil = c.getString("perfil");
             execinterface.testejson(Rsenha, Rprivilegio, Rperfil);

         } catch (JSONException e){
             e.printStackTrace();

         }

    }


}

JSONParser：

package ic.eng.br.testejson;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.List;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONException;
import org.json.JSONObject;

import android.util.Log;

public class JSONParser {

    static InputStream is = null;
    static JSONObject jObj = null;
    static String json = "";

    // constructor
    public JSONParser() {

    }

    public JSONObject getJSONFromUrl(String url) {

        // Making HTTP request
        try {
            // defaultHttpClient
            DefaultHttpClient httpClient = new DefaultHttpClient();
            HttpPost httpPost = new HttpPost(url);

            List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
            nameValuePairs.add(new BasicNameValuePair("login", "tiago"));
            nameValuePairs.add(new BasicNameValuePair("senha", "123456"));
            httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs));

            HttpResponse httpResponse = httpClient.execute(httpPost);
            HttpEntity httpEntity = httpResponse.getEntity();
            is = httpEntity.getContent();

        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    is, "iso-8859-1"), 8);
            StringBuilder sb = new StringBuilder();
            String line = null;
            while ((line = reader.readLine()) != null) {
                sb.append(line + "n");
            }
            is.close();
            json = sb.toString();
        } catch (Exception e) {
            Log.e("Buffer Error", "Error converting result " + e.toString());
        }

        // try parse the string to a JSON object
        try {
            jObj = new JSONObject(json);
        } catch (JSONException e) {
            Log.e("JSON Parser", "Error parsing data " + e.toString());
        }

        // return JSON String
        return jObj;

    }
}

Joson 

package ic.eng.br.testejson;

import android.view.View;

import org.json.JSONException;
import org.json.JSONObject;

public interface Json {

    void testejson (String Rsenha, String Rprivilegio, String Rperfil);
}

activity_main 

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

    <EditText
        android:id="@+id/edtUsuario"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10"
        android:textColor="#D3D3D3"
        tools:ignore="Autofill,LabelFor,TextFields"
        android:maxLines="1"
        android:singleLine="true"
        android:digits="abcdefghijklmnopqrstuvxywzç"/>

    <EditText
        android:id="@+id/edtSenha"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="15" />

        <Button
            android:id="@+id/btnLogin"
            android:layout_width="150dp"
            android:layout_height="wrap_content"
            android:text="Efetuar Login"
            android:layout_gravity="center_horizontal"/>

        <TextView
            android:id="@+id/textView1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="TextView"
            android:gravity="center"
            android:layout_gravity="center_horizontal"/>
        <TextView
            android:id="@+id/textView2"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="TextView"
            android:gravity="center"
            android:layout_gravity="center_horizontal"/>
        <TextView
            android:id="@+id/textView3"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:text="TextView"
            android:layout_gravity="center_horizontal"/>

    </LinearLayout>

</android.support.constraint.ConstraintLayout>

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