Json不会在第二时间更新结果

Question

我有一个活动，可以在URL json文件中进行搜索，因此3个参数从MainActivity的EditText传递到第二个活动（匿名），URL Json恢复了这三个值，结果通常显示出来，但是如果我返回MainActivity并更改EditTexts的值并单击“搜索”，则问题不会改变。

这是我的项目：

---

MainActivity.java

package com.example.dzweber.waslup;

import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.view.View;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import android.widget.AutoCompleteTextView;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity
    implements NavigationView.OnNavigationItemSelectedListener {
AutoCompleteTextView cat;


String[] categories={"informatique","infographie","mathématique","Génie civil","Biologie"};

@Override
protected void onCreate(Bundle savedInstanceState) {
    if(annonces.instance != null) {

            annonces.instance.finish();

    }
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);


    cat=(AutoCompleteTextView)findViewById(R.id.autoCompleteTextView2);
    ArrayAdapter adapter = new
            ArrayAdapter(this,android.R.layout.simple_list_item_1,categories);

    cat.setAdapter(adapter);
    cat.setThreshold(1);


    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                    .setAction("Action", null).show();
        }
    });

    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
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")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
    // Handle navigation view item clicks here.
    int id = item.getItemId();
    if (id == R.id.home) {

    }
    else if (id == R.id.login) {
        Intent i = new Intent(this,login.class);
        startActivity(i);
    }
     else if (id == R.id.avanced_search) {
        Intent i = new Intent(this,avanced_search.class);
        startActivity(i);
    }
    else if (id == R.id.annonces) {
        Intent i = new Intent(this,avanced_search.class);
        startActivity(i);
    }else if (id == R.id.nav_manage) {

    } else if (id == R.id.nav_share) {

    }

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

public void as(View view) {
    EditText loc;
    EditText key;
    loc = (EditText)findViewById(R.id.a_loc);
    key = (EditText)findViewById(R.id.a_keys);
    Intent intent = new Intent(getBaseContext(), annonces.class);
    intent.putExtra("ca", cat.getText().toString());
    intent.putExtra("lo",loc.getText().toString());
    intent.putExtra("ke", key.getText().toString());
    startActivity(intent);

}

public void connect(View view) {

}
}

annonces.java

package com.example.dzweber.waslup;

import android.app.ProgressDialog;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.os.AsyncTask;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import com.androidquery.AQuery;
import com.google.android.gms.appindexing.Action;
import com.google.android.gms.appindexing.AppIndex;
import com.google.android.gms.common.api.GoogleApiClient;

import org.json.JSONObject;

public class annonces extends AppCompatActivity
    implements NavigationView.OnNavigationItemSelectedListener {
public static ArrayList<annonce_item> Items = new ArrayList<annonce_item>();

public static TextView txtv;
public static String data = "";
String skey = "";
String sloc = "";
String scat = "";

String date="";
String loc="";
String cat="";
String vue="";
String titre="";
String id="";
/**
 * ATTENTION: This was auto-generated to implement the App Indexing API.
 * See https://g.co/AppIndexing/AndroidStudio for more information.
 */
private GoogleApiClient client;
public static annonces instance = null;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
   // fetchD p = new fetchD();
    //p.execute();
    instance = this;

    skey= getIntent().getStringExtra("ke");
    sloc= getIntent().getStringExtra("lo");
    scat= getIntent().getStringExtra("ca");

    setContentView(R.layout.activity_annonces);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    new AsyncCaller().execute();

    TextView t = (TextView) findViewById(R.id.testing);
    t.setText(scat);

    // String generate = "https://www.waslup.pw/generation-json";
    // String myurl = "https://www.waslup.pw/wp-content/uploads/wpdata.json";
    //  new MyAsyncTaskgetNews().execute(generate);
    //  new MyAsyncTaskgetNews().execute(myurl);





    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                    .setAction("Action", null).show();
        }
    });

    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);
    // 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();
}


@Override
public void finish() {
    super.finish();
    instance = null;
}

public void buclick(View view) {

     }


@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.annonces, 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")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
    // Handle navigation view item clicks here.
    int id = item.getItemId();
    if (id == R.id.home) {
        Intent i = new Intent(this,MainActivity.class);
        startActivity(i);
        finish();
    }
    else if (id == R.id.login) {
        Intent i = new Intent(this,login.class);
        startActivity(i);
    }
    else if (id == R.id.avanced_search) {
        Intent i = new Intent(this,avanced_search.class);
        startActivity(i);
    }
    else if (id == R.id.annonces) {
        Intent i = new Intent(this,MainActivity.class);
        startActivity(i);
    }else if (id == R.id.nav_manage) {

    } else if (id == R.id.nav_share) {

    }

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








class MyCustomAdapter extends BaseAdapter {
    ArrayList<annonce_item> Items = new ArrayList<annonce_item>();

    MyCustomAdapter(ArrayList<annonce_item> Items) {
        this.Items = Items;

    }


    @Override
    public int getCount() {
        return Items.size();
    }

    @Override
    public String getItem(int position) {
        return Items.get(position).ititre;

    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {
        LayoutInflater linflater = getLayoutInflater();
        View view1 = linflater.inflate(R.layout.activity_annonce_item, null);


        TextView id1 = (TextView) view1.findViewById(R.id.id);
        TextView date1 = (TextView) view1.findViewById(R.id.date);
        TextView cat1 = (TextView) view1.findViewById(R.id.cat);
        TextView loc1 = (TextView) view1.findViewById(R.id.loc);
        TextView titre1 = (TextView) view1.findViewById(R.id.titre);
        TextView vue1 = (TextView) view1.findViewById(R.id.vue);
        date1.setText(Items.get(i).idate);
        id1.setText(Items.get(i).iid);
        cat1.setText(Items.get(i).icat);
        loc1.setText(Items.get(i).iloc);
        titre1.setText(Items.get(i).ititre);
        vue1.setText(Items.get(i).ivue);

        return view1;

    }


}


















 /*
@Override
protected void onResume() {
    // TODO Auto-generated method stub
    super.onResume();

    new AsyncCaller().execute();

}*/

private class AsyncCaller extends AsyncTask<Void, Void, Void>
{
    ProgressDialog pdLoading = new ProgressDialog(annonces.this);

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

        //this method will be running on UI thread
        pdLoading.setMessage("/tChargement des annonces en cours ... ");
        pdLoading.show();
    }
    @Override
    protected Void doInBackground(Void... params) {
        try {

            URL url = new URL("https://www.waslup.pw/wp-admin/admin-ajax.php?action=do_ajax&fn=get_posts&count=10&key="+skey+"&cat="+scat+"&loc="+sloc);

            HttpURLConnection httpuc = (HttpURLConnection) url.openConnection();

            InputStream inputstream = httpuc.getInputStream();
            BufferedReader bf = new BufferedReader(new InputStreamReader(inputstream));

            String line ="";
            while(line != null){
                line = bf.readLine();
                data= data + line;
            }

            JSONArray JA = null;
            JA = new JSONArray(data);
            annonces.Items.removeAll(annonces.Items);
            for (int i=0 ; i<JA.length();i++){
                JSONObject JO =(JSONObject) JA.get(i);
                date =""+ JO.get("date");
                loc =""+ JO.get("loc");
                cat =""+ JO.get("Cat");
                vue =""+ JO.get("vue");
                titre =""+ JO.get("title");
                id =""+ JO.get("Id");

                annonces.Items.add(new annonce_item(id,date,loc,cat,vue,titre));


        }


    } catch (MalformedURLException e) {

        } catch (JSONException e) {

        } catch (IOException e) {

        }




        return null;
}

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

        //this method will be running on UI thread

        pdLoading.dismiss();
        final MyCustomAdapter myadpter = new MyCustomAdapter(Items);

        ListView ls = (ListView) findViewById(R.id.listannonce);
        ls.setAdapter(myadpter);
        ls.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                TextView titre = (TextView) view.findViewById(R.id.titre);
                Toast.makeText(getApplicationContext(), titre.getText(), Toast.LENGTH_LONG).show();
                myadpter.notifyDataSetChanged();
                TextView id2 = (TextView) view.findViewById(R.id.id);

                Intent intent = new Intent(getBaseContext(), annonce_details.class);
                intent.putExtra("id_from_annonces_activity", id2.getText());
                startActivity(intent);


            }
        });
    }

}
}

Answer 1

我检查了您的代码并解决了您的问题。

有两件事需要讨论。

1. 您的API根据本地化提供结果。如果我们更改前两个字段，结果将保持不变，并且Web服务仅会提取一个本地化为“ oran”的项目。但是，如果我们将本地化从“ oran”更改为“ alger”，则Web服务将显示4​​个结果。

2. 这是代码中的问题。您没有在数据字符串中正确连接结果。我已经更新了您的代码，现在您在宣布Activity中的AsyncCaller代码应类似于：

  

这是代码

 private class AsyncCaller extends AsyncTask<Void, Void, Void>
{
    ProgressDialog pdLoading = new ProgressDialog(annonces.this);

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

        //this method will be running on UI thread
        pdLoading.setMessage("/tChargement des annonces en cours ... ");
        pdLoading.show();
    }
    @SuppressLint("NewApi")
    @Override
    protected Void doInBackground(Void... params) {
        try {

            URL url = new URL("https://www.waslup.pw/wp-admin/admin-ajax.php?action=do_ajax&fn=get_posts&count=10&key="+skey+"&cat="+scat+"&loc="+sloc);

            HttpURLConnection httpuc = (HttpURLConnection) url.openConnection();

            InputStream inputstream = httpuc.getInputStream();
            BufferedReader bf = new BufferedReader(new InputStreamReader(inputstream));

            StringBuilder total = new StringBuilder();
            String line;
            while ((line = bf.readLine()) != null) {
                total.append(line).append('\n');
            }

            JSONArray JA = null;
            JA = new JSONArray(total.toString());
            annonces.Items.removeAll(annonces.Items);
            for (int i=0 ; i<JA.length();i++){
                JSONObject JO =(JSONObject) JA.get(i);
                date =""+ JO.get("date");
                loc =""+ JO.get("loc");
                cat =""+ JO.get("Cat");
                vue =""+ JO.get("vue");
                titre =""+ JO.get("title");
                id =""+ JO.get("Id");

                annonces.Items.add(new annonce_item(id,date,loc,cat,vue,titre));


        }


    } catch (MalformedURLException e) {

        } catch (JSONException e) {
            Log.d("js_ex:",e.toString());

        } catch (IOException e) {
            Log.d("io_ex:",e.toString());

        }




        return null;
}

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

        //this method will be running on UI thread

        pdLoading.dismiss();
        final MyCustomAdapter myadpter = new MyCustomAdapter(Items);

        ListView ls = (ListView) findViewById(R.id.listannonce);
        ls.setAdapter(myadpter);
        ls.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                TextView titre = (TextView) view.findViewById(R.id.titre);
                Toast.makeText(getApplicationContext(), titre.getText(), Toast.LENGTH_LONG).show();
                myadpter.notifyDataSetChanged();
                TextView id2 = (TextView) view.findViewById(R.id.id);

                Intent intent = new Intent(getBaseContext(), annonce_details.class);
                intent.putExtra("id_from_annonces_activity", id2.getText());
                startActivity(intent);


            }
        });
    }

}

  

在这段代码中，我添加了这一部分

StringBuilder total = new StringBuilder();
        String line;
        while ((line = bf.readLine()) != null) {
            total.append(line).append('\n');
        }

        JSONArray JA = null;
        JA = new JSONArray(total.toString());