用的TextView和复选框Listvew [英] Listvew with textview and checkbox

问题描述

我想与TextView的+复选框列表视图。我能够创建列表视图。我可以捕获ListView项选择。然而，当我试图捕捉复选框选择，取消选择，我得到一个空指针异常。怎样写setOnCheckedChangeListener（）的复选框。

 公共类LocationActivity延伸活动{@覆盖
保护无效的onCreate（捆绑savedInstanceState）{
    // TODO自动生成方法存根
    super.onCreate（savedInstanceState）;    的setContentView（R.layout.locationmain）;    ListView控件列表视图=（ListView控件）findViewById（R.id.listView1）;    字符串selectQuery =SELECT * FROM+ DatabaseHandler.TABLE_LOCATIONLABLES;
    SQLiteDatabase DB =新的数据库处理器（本）.getReadableDatabase（）;
    光标光标= db.rawQuery（selectQuery，NULL）;    最终名单＆LT;串GT; locLables =新的ArrayList＆LT;串GT;（）;    如果（指针！= NULL）{
        如果（cursor.moveToFirst（））{
            做{                locLables.add（cursor.getString（1））;            }而（cursor.moveToNext（））;
        }
    }    //的String [] = locLables新的String [] {家，大学，办公室};
    ArrayAdapter＆LT;串GT;适配器=新ArrayAdapter＆LT;串GT;（这一点，R.layout.locationmain_entry，R.id.textView12，locLables）;    // CB给出了一个空指针异常
    复选框CB =（复选框）listview.findViewById（R.id.checkBox12）;    cb.setOnCheckedChangeListener（新OnCheckedChangeListener（）{        @覆盖
        公共无效onCheckedChanged（CompoundButton buttonView，布尔器isChecked）{
            // TODO自动生成方法存根
            如果（器isChecked）{
                的System.out.println（选择）;
            }否则如果（！器isChecked）{
                的System.out.println（未选中）;
            }        }
    }）;
    listview.setAdapter（适配器）;
    listview.setOnItemClickListener（新OnItemClickListener（）{        @覆盖
        公共无效onItemClick（适配器视图＆LT;＆GT;为arg0，ARG1观，诠释ARG2，
                长ARG3）{
            // TODO自动生成方法存根
            Toast.makeText（getApplicationContext（），locLables.get（ARG2），Toast.LENGTH_SHORT）.show（）;
        }
    }）;
}
 

解决方案

您可以保持独立的adpater类，这样就可以很容易地achive这个....

 公共类bsAdapter延伸BaseAdapter
 {
   活动CNTX;
   公共bsAdapter（Activity上下文）
   {
     // TODO自动生成构造函数存根
     this.cntx =背景;   }   公众诠释getCount将（）
   {
     // TODO自动生成方法存根
     返回listview_arr.length;
   }  公共对象的getItem（INT位置）
  {
     // TODO自动生成方法存根
     返回listview_arr [位置]
  }  众长getItemId（INT位置）
  {
     // TODO自动生成方法存根
     返回listview_array.length;
  }  公共查看getView（最终诠释的立场，观点convertView，父母的ViewGroup）
  {
     查看排= NULL;    LayoutInflater吹气= cntx.getLayoutInflater（）;
    行= inflater.inflate（R.layout.search_list_item，NULL）;    TextView的电视=（TextView中）row.findViewById（R.id.title）;
    复选框CB =（复选框）row.findViewById（R.id.cb01）;
    tv.setText（listview_arr [位置]）;    cb.setOnClickListener（新OnClickListener（）{    公共无效的onClick（视图v）{    如果（cb.ischecked）
    {
       //乌尔code
    }    否则//乌尔code    }
  }）;  返回行;
  }
 }
 

I want to have a listview with textview + check box. I was able to create the listview. I can capture listview item select. However when I try to capture check box select, unselect I get a null pointer exception. How to write the setOnCheckedChangeListener() for the check box..

public class LocationActivity extends Activity{



@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);

    setContentView(R.layout.locationmain);

    ListView listview = (ListView) findViewById(R.id.listView1);

    String selectQuery = "SELECT  * FROM " +     DatabaseHandler.TABLE_LOCATIONLABLES;
    SQLiteDatabase db = new DatabaseHandler(this).getReadableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);

    final List<String> locLables = new ArrayList<String>();

    if(cursor != null){
        if (cursor.moveToFirst()) {
            do {

                locLables.add(cursor.getString(1));

            } while (cursor.moveToNext());
        }
    }

    //String[] locLables = new String[] {"Home","University","Office"};
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, R.layout.locationmain_entry,R.id.textView12, locLables);

    //cb gives a null pointer exception
    CheckBox cb = (CheckBox) listview.findViewById(R.id.checkBox12);

    cb.setOnCheckedChangeListener(new OnCheckedChangeListener() {

        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            // TODO Auto-generated method stub
            if(isChecked){
                System.out.println("selected");
            }else if(!isChecked){
                System.out.println("not selected");
            }

        }
    });     
    listview.setAdapter(adapter);


    listview.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
                long arg3) {
            // TODO Auto-generated method stub
            Toast.makeText(getApplicationContext(), locLables.get(arg2), Toast.LENGTH_SHORT).show();
        }
    });
}

解决方案

You can maintain seperate adpater class so that you can achive this easily....

 public class bsAdapter extends BaseAdapter
 {
   Activity cntx;
   public bsAdapter(Activity context)
   {
     // TODO Auto-generated constructor stub
     this.cntx=context;

   }

   public int getCount()
   {
     // TODO Auto-generated method stub
     return listview_arr.length;
   }

  public Object getItem(int position)
  {
     // TODO Auto-generated method stub
     return listview_arr[position];
  }

  public long getItemId(int position)
  {
     // TODO Auto-generated method stub
     return listview_array.length;
  }

  public View getView(final int position, View convertView, ViewGroup parent)
  {
     View row=null;

    LayoutInflater inflater=cntx.getLayoutInflater();
    row=inflater.inflate(R.layout.search_list_item, null);

    TextView tv=(TextView)row.findViewById(R.id.title);
    CheckBox cb=(CheckBox)row.findViewById(R.id.cb01);


    tv.setText(listview_arr[position]);

    cb.setOnClickListener(new OnClickListener(){

    public void onClick(View v) {

    if(cb.ischecked)
    {
       //ur code
    }

    else //ur code

    }
  });

  return row;
  }
 }

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