Android的listview花费很多时间来加载

Question

我有一个自定义适配器的列表视图和它的工作正常。但是将数据加载到列表视图需要15秒以上的时间。请告诉我什么是问题以及为什么花费太多时间？这是我的代码。提前致谢！

public class Listadapter extends BaseAdapter { 
    CheckBox checkBox; 
    boolean index[]; 
    boolean[] itemChecked; 
    ApplicationInfo entry; 
    String[] itempkg; 
    private Context mContext; 
    private List<ApplicationInfo> mListAppInfo; 
    private PackageManager mPackManager; 
    private ArrayList<Boolean> checkList = new ArrayList<Boolean>(); 

    public Listadapter(Context applicationContext, List<ApplicationInfo> installedApplication, PackageManager packageManager) { 
     //super(applicationContext,textViewResourceId,installedApplication); 
     super(); 
     this.mContext = applicationContext; 
     this.mListAppInfo = installedApplication; 
     index = new boolean[installedApplication.size()]; 
     this.mPackManager = packageManager; 
     for (int i = 0; i < installedApplication.size(); i++) { 
      checkList.add(false); 
      itemChecked = new boolean[installedApplication.size()]; 
      itempkg = new String[installedApplication.size()]; 
     } 
    } 

    @Override 
    public int getCount() { 
     return mListAppInfo.size(); 
     //return ((null != mListAppInfo) ? mListAppInfo.size() : 0); 
    } 

    @Override 
    public Object getItem(int position) { 
     // index = new boolean[mListAppInfo.size()]; 
     return mListAppInfo.get(position); 
    } 

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

    @Override 
    public View getView(final int position, View convertView, ViewGroup parent) { 
     // get the selected entry 

     final ViewHolder holder; 

     // LayoutInflater inflater = (LayoutInflater) mContext.getLayoutInflater(); 
     LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 

     if (convertView == null) { 
      convertView = inflater.inflate(R.layout.list_item, null); 
      holder = new ViewHolder(); 
      // reference to convertView 
      holder.tvAppName = (TextView) convertView 
        .findViewById(R.id.textView1); 
      holder.tvPkgName = (TextView) convertView 
        .findViewById(R.id.textView); 
      holder.checkBox = (CheckBox) convertView 
        .findViewById(R.id.checkBox1); 
      holder.ivAppIcon = (ImageView) convertView 
        .findViewById(R.id.imageView); 

      convertView.setTag(holder); 
      // holder.ck1.setTag(packageList.get(position)); 

     } else { 

      holder = (ViewHolder) convertView.getTag(); 
     } 
     entry = mListAppInfo.get(position); 

     holder.ivAppIcon.setImageDrawable(entry.loadIcon(mPackManager)); 
     holder.tvAppName.setText(entry.loadLabel(mPackManager)); 
     holder.tvPkgName.setText(entry.packageName); 
     holder.checkBox.setChecked(false); 

     if (itemChecked[position]) 
      holder.checkBox.setChecked(true); 
     else 
      holder.checkBox.setChecked(false); 

     holder.checkBox.setOnClickListener(new OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       // TODO Auto-generated method stub 
       if (holder.checkBox.isChecked()) { 
        itemChecked[position] = true; 
        // SharedPreferences preferences = mContext.getSharedPreferences("YOUR_APP_NAME", Context.MODE_PRIVATE); 
        // SharedPreferences.Editor edit = preferences.edit(); 
        // edit.putBoolean("checkbox_" + position, true); 
        // edit.commit(); 
        // editor.putBoolean("CheckBoxState" + position, true); 
       } else { 
        itemChecked[position] = false; 
        // editor.putBoolean("CheckBoxState" + position, false); 
        // SharedPreferences preferences = mContext.getSharedPreferences("YOUR_APP_NAME", Context.MODE_PRIVATE); 
        // SharedPreferences.Editor edit = preferences.edit(); 
        // edit.putBoolean("checkbox_" + position, false); 
        // edit.commit(); 
       } 
      } 
     }); 
     return convertView; 
    } 

    public void setItemChecked3(boolean[] items3) { 
     itemChecked = items3; 
    } 

    public void setItemChecked2(boolean[] items2) { 
     itemChecked = items2; 
    } 

    public void setItemChecked1(boolean[] items1) { 
     itemChecked = items1; 
    } 

    private class ViewHolder { 
     ImageView ivAppIcon; 
     TextView tvAppName; 
     TextView tvPkgName; 
     CheckBox checkBox; 
    } 

} 

Answer 1

我的解决方案是：使用RecyclerView而不是ListView。

看看下面的示例代码，希望它有帮助。

public class ViewQuestionActivity extends AppCompatActivity { 

    final String TAG = "my_log"; 
    private RecyclerView recyclerView; 
    private RecyclerView.Adapter<MyViewHolder> mAdapter; 

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


     mAdapter = new RecyclerView.Adapter<QuestionNameViewHolder>() { 
      @Override 
      public QuestionNameViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { 
       View v = LayoutInflater.from(parent.getContext()).inflate(
         android.R.layout.simple_list_item_1, 
         parent, 
         false); 
       QuestionNameViewHolder vh = new QuestionNameViewHolder(v); 
       return vh; 
      } 

      @Override 
      public void onBindViewHolder(QuestionNameViewHolder vh, int position) { 
       TextView tv = (TextView) vh.itemView; 
       tv.setText(questionNameList.get(position)); 
       tv.setCompoundDrawablesWithIntrinsicBounds(R.drawable.ic_stars_black, 0, 0, 0); 
      } 

      @Override 
      public int getItemCount() { 
       return questionNameList.size(); 
      } 
     }; 
     recyclerView.setLayoutManager(new LinearLayoutManager(this)); 
     recyclerView.setAdapter(mAdapter); 

    } 

    //----------------------------------------------------------------------------------------- 

    // inner class ViewHolder 
    private class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener { 

     public MyViewHolder(View v) { 
      super(v); 
      v.setOnClickListener(this); 
     } 

     @Override 
     public void onClick(View v) { 
      String questionName = ((TextView) v).getText().toString(); 
      Toast.makeText(getApplicationContext(), getString(R.string.msg_go_details) + questionName, Toast.LENGTH_LONG).show(); 
      Question question = findQuestionFromName(questionName); 
      Intent i = new Intent(ViewQuestionActivity.this, QuestionDetailActivity.class); 
      i.putExtra("questionObject", question); 
      startActivity(i); 
     } 
    } 

}