关于listviwe出错的问题？

Question

package listview.Package; import java.util.HashMap; import java.util.List; import java.util.Map; import android.app.Activity; import android.os.Bundle; //import android.widget.ArrayAdapter; import android.widget.ListView; import android.widget.SimpleAdapter; public class ListviewActivity extends Activity { private ListView list;    // private ArrayAdapter<String> arrayadapter;     private SimpleAdapter simpleAdapter;     //String[]data={"慕课网1","慕课网2","慕课网3"};     private List<Map<String, Object>> datalist;     public void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.listviwe);         list=(ListView) findViewById(R.id.listView1);         //arrayadapter=new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,data);         list.setAdapter(simpleAdapter);         simpleAdapter=new SimpleAdapter(this,getdata(),R.layout.itme, new String[]{"img","text"},          new int[]{R.id.imageView1,R.id.textView1});            }     private List<Map<String, Object>> getdata(){      for(int i=0;i<10;i++){      Map<String, Object> map =new HashMap<String, Object>();      map.put("img", R.drawable.ic_launcher);      map.put("text", "慕课网"+i);      datalist.add(map);}    return datalist;     } }运行到模拟器，程序立马就停，logcat打印说是空指针异常，请问哪里错了，怎样改正。。！？

Answer 1

先new adapter 再setAdapter() 应该就可以了

Answer 2

1. datalist没有初始化
   

2. 先初始化simpleAdapter，然后list.setAdapter
   

Answer 3

一楼    正解 666

Answer 4

datalist没有初始化.

List<Map<String, Object>> datalist = new ArrayList<Map<String, Object>>();