Android 开发笔记 -- baseAdapter的getview方法重复执行问题

    在实现baseAdapter子类的时候，重载了getview方法来实现自己的Adapter对象，但是在debug的过程中发现，这个getview会不停的被调用，导致了listview中显示不出我们需要的东西。
   关键问题，在于我们没有给设定listview的长度是多少，所以无法来确定到底需要绘制多少我们自定的view在listview中，所以我们需要在布局文件中对于listview的高度进行设定，可以选择fill_parent或者设定数值高度。
   

<LinearLayout xmlns:android=""
    xmlns:tools="" android:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:id="@+id/appBar"
        android:layout_weight="1"/>
    <!--<LinearLayout-->
        <!--android:layout_width="fill_parent"-->
        <!--android:layout_height="wrap_content"-->
        <!-->-->
        <ListView
            android:layout_width="fill_parent"
            android:layout_height="50dip"
            android:id="@+id/listview" />
        <!--</LinearLayout>-->

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:id="@+id/rank"
        android:layout_weight="1"/>
</LinearLayout>

   这样再设置自己的Adapter时候就可以正确显示了
  上代码：
   

package com.example.dolby.webviewtest;

import android.content.Context;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;

import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonArrayRequest;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.Volley;

import org.json.JSONArray;
import org.json.JSONObject;
import org.w3c.dom.Text;

import java.util.ArrayList;
import java.util.Date;


//class jobinfo
//{
//    public String url;
//    public String name;
//}

public class MainActivity extends ActionBarActivity {

    private TextView text;
    private ListView infolist;
    private ArrayList<JSONObject> jsData;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        text = (TextView)findViewById(R.id.appBar);
        jsData = new ArrayList<JSONObject>();
        infolist = (ListView)findViewById(R.id.listview);
        startLoadInfo();


    }


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

    private void startLoadInfo()
    {
        RequestQueue queue = Volley.newRequestQueue(this);
        String jsonurl = "http://jobdev.sinaapp.com/api/getinfoList";
        JsonArrayRequest jsRequest = new JsonArrayRequest(jsonurl,new Response.Listener<JSONArray>() {
            @Override
            public void onResponse(JSONArray response) {
                //Log.d("first is " , ""  + response.getJSONObject(0));
                try{
                    //text.setText(response.getJSONObject(0).getString("name"));
                    for(int i = 0; i < response.length() ; i++)
                    {
                        jsData.add(response.getJSONObject(i));
                    }
                    jsonAdapter adapter = new jsonAdapter(MainActivity.this);
                    infolist.setAdapter(adapter);

                }
                catch(Exception e)
                {
                    Log.d("json get exception",e.getMessage());
                }

            }

        },new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                Log.d("json Request Error",error.getMessage());
            }
        });
        queue.add(jsRequest);
    }

    class jsonAdapter extends BaseAdapter
    {
        Context m_context;
        public jsonAdapter(Context context)
        {
            super();
            m_context = context;
        }
        @Override
        public int getCount(){
            return jsData.size();
        }

        @Override
        public Object getItem(int position) {
            return null;
        }

        @Override
        public long getItemId(int position) {
            return 0;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            TextView view = new TextView(m_context);
            String name = "";
            try{
                name = jsData.get(position).getString("name");
            }catch(Exception e){
                Log.d("haha error exception","nick");
            }
            view.setText(name);
            return view;
        }
    }
}