在片段中实现AsyncTask

时间：2014-07-22 17:19:27

标签： java android android-fragments android-listview android-asynctask

现在我有三个可滚动的标签片段，每个片段都包含已安装的应用列表。但是，当我按下按钮进入活动然后滚动列表视图时，它非常慢。

enter image description here

我试图在我的片段中创建一个AsyncTask子类，并在doInBackground（）中准备我的适配器，并在onPostExecute（）中调用setAdapter。

我试过这些：

implement AsyncTask in Fragment android

http://javatechig.com/android/how-to-get-list-of-installed-apps-in-android

但运气不太好。

这是我修改后的代码：

package com.spicycurryman.getdisciplined10.app;

import android.content.pm.ApplicationInfo;
import android.content.pm.PackageInfo;
import android.content.pm.PackageItemInfo;
import android.content.pm.PackageManager;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;

import com.ibc.android.demo.appslist.app.ApkAdapter;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;


public class InstalledAppActivity extends Fragment
        implements OnItemClickListener {

    PackageManager packageManager;
    ListView apkList;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        setHasOptionsMenu(true);
        View rootView = inflater.inflate(R.layout.user_installed, container, false);
        AppBoost appBoost = new AppBoost();
        appBoost.execute(apkList);


        return rootView;

    }



    private class AppBoost extends AsyncTask{
        ListView apkList;

        @Override
        protected Object doInBackground(Object[] objects) {
            packageManager = getActivity().getPackageManager();
            List<PackageInfo> packageList = packageManager
                    .getInstalledPackages(PackageManager.GET_PERMISSIONS);

            List<PackageInfo> packageList1 = new ArrayList<PackageInfo>();

        /*To filter out System apps*/
            for(PackageInfo pi : packageList) {
                boolean b = isSystemPackage(pi);
                if(!b) {
                    packageList1.add(pi);
                }
            }

            //sort by application name

            final PackageItemInfo.DisplayNameComparator comparator = new PackageItemInfo.DisplayNameComparator(packageManager);

            Collections.sort(packageList1, new Comparator<PackageInfo>() {
                @Override
                public int compare(PackageInfo lhs, PackageInfo rhs) {
                    return comparator.compare(lhs.applicationInfo, rhs.applicationInfo);
                }


            });


            apkList.setAdapter(new ApkAdapter(getActivity(), packageList1, packageManager));

            apkList.setOnItemClickListener((OnItemClickListener) this);


            return apkList;
        }




    }

    /**
     * Return whether the given PackgeInfo represents a system package or not.
     * User-installed packages (Market or otherwise) should not be denoted as
     * system packages.
     *
     * @param pkgInfo
     * @return boolean
     */
    private boolean isSystemPackage(PackageInfo pkgInfo) {
        return ((pkgInfo.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0) ? true
                : false;
    }


// Don't need in Fragment
/*@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    inflater.inflate(R.menu.block, menu);
   // super.onCreateOptionsMenu(menu,inflater);
}*/

    @Override
    public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {

    }
}

我不确定我做错了什么。当前标签中没有显示任何内容，但似乎我正确地实现了所有内容。

编辑：这是我的适配器： 

package com.ibc.android.demo.appslist.app;

import android.app.Activity;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.graphics.drawable.Drawable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.CheckBox;
import android.widget.TextView;
import android.view.View.OnClickListener;

import com.spicycurryman.getdisciplined10.app.R;

import java.util.List;

public class ApkAdapter extends BaseAdapter {


    List<PackageInfo> packageList;
    Activity context;
    PackageManager packageManager;
    boolean[] itemChecked;

    public ApkAdapter(Activity context, List<PackageInfo> packageList,
                      PackageManager packageManager) {
        super();
        this.context = context;
        this.packageList = packageList;
        this.packageManager = packageManager;
        itemChecked = new boolean[packageList.size()];
    }

    private class ViewHolder {
        TextView apkName;
        CheckBox ck1;
    }

    public int getCount() {
        return packageList.size();
    }

    public Object getItem(int position) {
        return packageList.get(position);
    }

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

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {
        final ViewHolder holder;

        LayoutInflater inflater = context.getLayoutInflater();

        if (convertView == null) {
            convertView = inflater.inflate(R.layout.installed_apps, null);
            holder = new ViewHolder();

            holder.apkName = (TextView) convertView
                    .findViewById(R.id.appname);
            holder.ck1 = (CheckBox) convertView
                    .findViewById(R.id.checkBox1);

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

        } else {

            holder = (ViewHolder) convertView.getTag();
        }
        // ViewHolder holder = (ViewHolder) convertView.getTag();
        PackageInfo packageInfo = (PackageInfo) getItem(position);

        Drawable appIcon = packageManager
                .getApplicationIcon(packageInfo.applicationInfo);
        String appName = packageManager.getApplicationLabel(
                packageInfo.applicationInfo).toString();
        appIcon.setBounds(0, 0, 75, 75);
        holder.apkName.setCompoundDrawables(appIcon, null, null, null);
        holder.apkName.setCompoundDrawablePadding(15);
        holder.apkName.setText(appName);
        holder.ck1.setChecked(false);

        if (itemChecked[position])
            holder.ck1.setChecked(true);
        else
            holder.ck1.setChecked(false);

        holder.ck1.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                if (holder.ck1.isChecked())
                    itemChecked[position] = true;
                else
                    itemChecked[position] = false;
            }
        });

        return convertView;

    }



}

2 个答案:

答案 0 :(得分：0)

使用getView方法，您会遇到PackageManager的查询，这会花费时间导致滚动延迟。

Drawable appIcon = packageManager.getApplicationIcon(packageInfo.applicationInfo);
String appName = packageManager.getApplicationLabel(packageInfo.applicationInfo).toString();

要解决此问题，您可以在填充列表之前使用异步任务获取所有图标和应用程序名称，或者使用getView方法执行asyncTask以获取这些数据。

答案 1 :(得分：0)

以下是一个例子：

PackageManager packageManager;
    ListView apkList;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        setHasOptionsMenu(true);
        View rootView = inflater.inflate(R.layout.user_installed, container, false);
        packageManager = getActivity().getPackageManager();


        /*To filter out System apps*/

        apkList = (ListView) rootView.findViewById(R.id.applist);

        new LoadApplications(getActivity().getApplicationContext()).execute();


        return rootView;
    }

    /**
     * Return whether the given PackageInfo represents a system package or not.
     * User-installed packages (Market or otherwise) should not be denoted as
     * system packages.
     *
     * @param pkgInfo
     * @return boolean
     */
    private boolean isSystemPackage(PackageInfo pkgInfo) {
        return ((pkgInfo.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0) ? true
                : false;
    }

    private boolean isSystemPackage1(PackageInfo pkgInfo) {
        return ((pkgInfo.applicationInfo.flags & ApplicationInfo.FLAG_UPDATED_SYSTEM_APP) != 0) ? false
                : true;
    }


// Don't need in Fragment
/*@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    inflater.inflate(R.menu.block, menu);
   // super.onCreateOptionsMenu(menu,inflater);
}*/

    @Override
    public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {

    }


    private class LoadApplications extends AsyncTask<Void, Void, Void> {

        Context mContext;

        private ProgressDialog pDialog;
        List<PackageInfo> packageList1 = new ArrayList<PackageInfo>();

        public LoadApplications(Context context){
            Context mContext = context;
        }




        @Override
        protected Void doInBackground(Void... params) {

            List<PackageInfo> packageList = packageManager
                    .getInstalledPackages(PackageManager.GET_PERMISSIONS);


          /*  List<ApplicationInfo> list = mContext.getPackageManager().getInstalledApplications(PackageManager.GET_UNINSTALLED_PACKAGES);


            for(int n = 0;n<list.size();n++){
                if ((list.get(n).flags & ApplicationInfo.FLAG_UPDATED_SYSTEM_APP))
            }*/


            for(PackageInfo pi : packageList) {
                boolean b = isSystemPackage(pi);
                boolean c = isSystemPackage1(pi);

                if(!b || !c ) {
                    packageList1.add(pi);
                }
            }

            //sort by application name

            final PackageItemInfo.DisplayNameComparator comparator = new PackageItemInfo.DisplayNameComparator(packageManager);

            Collections.sort(packageList1, new Comparator<PackageInfo>() {
                @Override
                public int compare(PackageInfo lhs, PackageInfo rhs) {
                    return comparator.compare(lhs.applicationInfo, rhs.applicationInfo);
                }
            });



            return null;
        }
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