显示从Fragment中的JSON URL解析的Listview

时间：2014-08-30 00:12:42

标签： android listview

我是机器人初中。

我正在尝试将JSON URL解析为片段并在Listview中显示它。我被各种教程困住了几个小时，每个人都遵循不同的方式。

所以，请这就是我所达到的，让我知道我应该做些什么才能让它发挥作用！感谢您的帮助 - 很多代码都是从不同的教程中复制/粘贴，加上JSON文件只是应用在不同的教程中，基本的我只是试图让它显示出来。

activity_main.xml中

<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/pager"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.sampleapp.MainActivity" />

fragment_main.xml 

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.sampleapp.MainActivity$PlaceholderFragment" >

    <TextView
        android:id="@+id/section_label"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <TextView
        android:id="@+id/text1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/section_label"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="171dp"
        android:text="Large Text"
        android:textAppearance="?android:attr/textAppearanceLarge" />

</RelativeLayout>

itune_frag.xml 

 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:orientation="vertical" > 

     <TextView android:id="@+id/vehicleType" 
         android:layout_width="wrap_content" 
         android:layout_height="wrap_content" 
         android:text="vehicleType" /> 

     <TextView android:id="@+id/vehicleColor" 
         android:layout_width="wrap_content" 
         android:layout_height="wrap_content" 
         android:text="vehicleColor" /> 

</LinearLayout>

fav_frag.xml 

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin">

    <TextView
        android:id="@+id/text1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/section_label"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="171dp"
        android:text="Favvvvvv"
        android:textAppearance="?android:attr/textAppearanceLarge" />

</RelativeLayout>

MainActivity.java 

package com.example.sampleapp;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

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

import android.app.Activity;
import android.app.ActionBar;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.content.Context;
import android.support.v13.app.FragmentPagerAdapter;
import android.os.Bundle;
import android.support.v4.view.ViewPager;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;

public class MainActivity extends Activity implements ActionBar.TabListener {

    SectionsPagerAdapter mSectionsPagerAdapter;
    ViewPager mViewPager;

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


        final ActionBar actionBar = getActionBar();
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

        mSectionsPagerAdapter = new SectionsPagerAdapter(getFragmentManager());


        mViewPager = (ViewPager) findViewById(R.id.pager);
        mViewPager.setAdapter(mSectionsPagerAdapter);


        mViewPager
                .setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
                    @Override
                    public void onPageSelected(int position) {
                        actionBar.setSelectedNavigationItem(position);
                    }
                });

        actionBar.addTab(actionBar.newTab().setText("iTunes List").setTabListener(this));
        actionBar.addTab(actionBar.newTab().setText("Favourite").setTabListener(this));

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    public void onTabSelected(ActionBar.Tab tab,
            FragmentTransaction fragmentTransaction) {
        mViewPager.setCurrentItem(tab.getPosition());
    }

    @Override
    public void onTabUnselected(ActionBar.Tab tab,
            FragmentTransaction fragmentTransaction) {
    }

    @Override
    public void onTabReselected(ActionBar.Tab tab,
            FragmentTransaction fragmentTransaction) {
    }

    /**
     * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
     * one of the sections/tabs/pages.
     */
    public class SectionsPagerAdapter extends FragmentPagerAdapter {

        public SectionsPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            Fragment fragment = new Fragment();  
            switch (position) {  
            case 0:  
                return fragment = new iTuneFragment();  
            case 1:  
                return fragment = new favFragment();  
            default:  
                break;  
            }
            return fragment; 
        }

        @Override
        public int getCount() {
            return 2;
        }

        @Override
        public CharSequence getPageTitle(int position) {
            return null;
        }
    }


}

iTuneFragment.java 

    class iTuneFragment extends Fragment {

    JSONArray user = null;
    ArrayList<HashMap<String, String>> jsonlist = new ArrayList<HashMap<String, String>>();

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        // Inflate the layout for this fragment

        iTuneList ll = new iTuneList();

        return inflater.inflate(R.layout.itune_frag, container, false);
    }

}

iTuneList.java 

public final class iTuneList extends ListFragment {

    // URL to get JSON Array
    private static String url = "http://docs.blackberry.com/sampledata.json";

    // JSON Node Names
    private static final String VTYPE = "vehicleType";
    private static final String VCOLOR = "vehicleColor";

    JSONArray user = null;

    ArrayList<HashMap<String, String>> jsonlist = new ArrayList<HashMap<String, String>>();

    public iTuneList() {
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onActivityCreated(savedInstanceState);
        new asy().execute();
    }

    private class asy extends
            AsyncTask<Void, Void, ArrayList<HashMap<String, String>>> {

        @Override
        protected ArrayList<HashMap<String, String>> doInBackground(
                Void... params) {
            // Creating new JSON Parser
            JSONParser jParser = new JSONParser();

            // Getting JSON from URL
            JSONArray json = jParser.getJSONFromUrl(url);
            for (int i = 0; i < json.length(); i++) {

                try {
                    JSONObject c = json.getJSONObject(i);

                    String vtype = c.getString(VTYPE);
                    String vcolor = c.getString(VCOLOR);
                    Log.e("iTuneList.java", "JSON: " + vtype);
                    HashMap<String, String> map = new HashMap<String, String>();

                    // Add child node to HashMap key & value
                    map.put(VTYPE, vtype);
                    map.put(VCOLOR, vcolor);
                    jsonlist.add(map);

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

        @Override
        protected void onPostExecute(
                ArrayList<HashMap<String, String>> result) {
            // TODO Auto-generated method stub
            super.onPostExecute(result);
            ListAdapter adapter = new SimpleAdapter(getActivity(), result,
                    R.layout.itune_frag, new String[] { VTYPE, VCOLOR, },
                    new int[] { R.id.vehicleType, R.id.vehicleColor });
            setListAdapter(adapter);
        }

    }
}

此外，我有使用getJSONFromUrl的JSONParser.java - 看起来很好的包装类。而且，favFragment.java是不同的故事，现在不介意它，它工作正常。

THAAAAAAAAAANKS !!

2 个答案:

答案 0 :(得分：0)

    public static class iTuneList extends ListFragment {

    // URL to get JSON Array
    private static String url = "http://docs.blackberry.com/sampledata.json";

    // JSON Node Names
    private static final String VTYPE = "vehicleType";
    private static final String VCOLOR = "vehicleColor";

    JSONArray user = null;

    ArrayList<HashMap<String, String>> jsonlist = new ArrayList<HashMap<String, String>>();

    public iTuneList() {
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onActivityCreated(savedInstanceState);
        new asy().execute();
    }

    private class asy extends
            AsyncTask<Void, Void, ArrayList<HashMap<String, String>>> {

        @Override
        protected ArrayList<HashMap<String, String>> doInBackground(
                Void... params) {
            // Creating new JSON Parser
            JSONParser jParser = new JSONParser();

            // Getting JSON from URL
            JSONArray json = jParser.getJSONFromUrl(url);
            for (int i = 0; i < json.length(); i++) {

                try {
                    JSONObject c = json.getJSONObject(i);

                    String vtype = c.getString(VTYPE);
                    String vcolor = c.getString(VCOLOR);

                    HashMap<String, String> map = new HashMap<String, String>();

                    // Add child node to HashMap key & value
                    map.put(VTYPE, vtype);
                    map.put(VCOLOR, vcolor);
                    jsonlist.add(map);

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

        @Override
        protected void onPostExecute(
                ArrayList<HashMap<String, String>> result) {
            // TODO Auto-generated method stub
            super.onPostExecute(result);
            ListAdapter adapter = new SimpleAdapter(getActivity(), result,
                    R.layout.itune_frag, new String[] { VTYPE, VCOLOR, },
                    new int[] { R.id.vehicleType, R.id.vehicleColor });
            setListAdapter(adapter);
        }

    }
}

将此作为您的片段。

答案 1 :(得分：0)

我建议您控制适配器中发生的事情。尝试扩展Adapter类，然后指定如何将数据分配给Views。基本上创建适配器，在你的情况下采用哈希映射的ArrayList作为源idealy通过构造函数传递引用并将其保持为私有字段。然后在GetView(int position ...other args)中获取正确位置的值并创建您从此方法返回的视图。
请查看此链接以获取更多详细信息
Link1

Link2

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