applicationinfo 中获取的class name是空的

老师，我想通过使用applicaitoninfo中的class name和package name来通过使用componentname来实现软件的跳转，但是我获取的class name是空的

package com.example.jeremychen.assignment4_2;

import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.pm.ApplicationInfo;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.List;

/**
* Created by jeremychen on 2018/5/23.
*/

public class AppAdapter extends BaseAdapter {
   private List<ApplicationInfo> appList;
   private Context context;
   public AppAdapter(List<ApplicationInfo> list, Context context) {
       this.appList = list;
       this.context = context;
   }

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

   @Override
   public Object getItem(int position) {
       return appList.get(position);
   }

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

   @Override
   public View getView(final int position, View convertView, ViewGroup parent) {
       LayoutInflater inflater = LayoutInflater.from(context);
       convertView = inflater.inflate(R.layout.content_layout,null);
       ImageView imageView = (ImageView) convertView.findViewById(R.id.imageView);
       TextView textView = (TextView) convertView.findViewById(R.id.App_textview);
       imageView.setImageDrawable(appList.get(position).loadIcon(context.getPackageManager()));
       textView.setText(appList.get(position).loadLabel(context.getPackageManager()));

       convertView.setOnClickListener(new View.OnClickListener() {
           @Override
           public void onClick(View v) {
               String Package_name = appList.get(position).packageName;
               String Class_name = appList.get(position).;
               ComponentName componentName = new ComponentName(Package_name, Class_name);
               Intent intent = new Intent();
               intent.setComponent(componentName);
               context.startActivity(intent);
           }
       });
       return convertView;
   }

   public void refresh(List<ApplicationInfo> list)
   {
       appList = list;
       notifyDataSetChanged();
   }
}

这是我的adaptor类中使用了点击监听！！