Question

我在列表视图中有一个已安装应用的片段，旁边有一个切换按钮。

enter image description here

我想要做的是当用户点击按钮并且它处于打开状态时，我希望它在用户返回时退出，退出应用程序或重新启动活动。

我做过研究，我知道这是可以实现的，但我不知道如何实现这一点。

Listview : How to remain highlighted/selected after press back button?

我试过这个但是没有成功。

这是我的适配器类：

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.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Switch;
import android.widget.TextView;

import com.spicycurryman.getdisciplined10.app.R;

import java.util.List;

public class ApkAdapter extends BaseAdapter {


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



    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;
        Switch 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= (Switch)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, 80, 80);
        holder.apkName.setCompoundDrawables(appIcon, null, null, null);
        holder.apkName.setCompoundDrawablePadding(15);
        holder.apkName.setText(appName);
        holder.ck1.setChecked(false);

        //What would I put here!?!?

        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;
                    Log.i("This is", " checked: " + position);

                }

                else {
                    itemChecked[position] = false;
                    Log.i("This is", " not checked: " + position);

                }
            }
        });

        return convertView;

    }




}

这是我的InstalledAppActivity片段类：

package com.spicycurryman.getdisciplined10.app;

import android.app.ProgressDialog;
import android.content.Context;
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);
        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) {
        //ApkAdapter apkAdapter=(ApkAdapter)apkList.getAdapter();

    }


    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;
        }

        @Override
        protected void onCancelled() {
            super.onCancelled();
        }

        @Override
        protected void onPreExecute() {
            pDialog = new ProgressDialog(InstalledAppActivity.this.getActivity());
            pDialog.setMessage("Loading your apps...");
            pDialog.show();

        }

        @Override
        protected void onPostExecute(Void result) {

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

            if (pDialog.isShowing()){
                pDialog.dismiss();

            }


            super.onPostExecute(result);
        }


        @Override
        protected void onProgressUpdate(Void... values) {
            super.onProgressUpdate(values);
        }
    }



}

我想弄清楚我需要做些什么修改，以便在按下后退按钮，应用程序关闭/重新启动等时保持检查开关按钮。

编辑：

我在

中收到错误

holder.ck1.setChecked（sharedPrefs.getBoolean（“NameOfThingToSave”，true））;

 @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= (Switch)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, 80, 80);
        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;
                    Log.i("This is", " checked: " + position);
                    SharedPreferences.Editor editor = context.getSharedPreferences("com.ibc.android.demo.appslist.app", Context.MODE_PRIVATE).edit();
                    editor.putBoolean("checkBox1", true);
                    editor.commit();

                }

                else {
                    itemChecked[position] = false;
                    Log.i("This is", " not checked: " + position);
                    SharedPreferences.Editor editor = context.getSharedPreferences("com.ibc.android.demo.appslist.app", Context.MODE_PRIVATE).edit();
                    editor.putBoolean("checkBox1", false);
                    editor.commit();

                }
            }
        });

        sharedPrefs = getSharedPreferences("com.example.xyle", Context.MODE_PRIVATE);
        holder.ck1.setChecked(sharedPrefs.getBoolean("NameOfThingToSave", true));




        return convertView;

    }

Answer 1

在android中存储某些对象状态的常用方法与SharedPreferences有关。您基本上将键值对存储在应用程序的专用文件中。在您的活动中，最合理的是它的onDestroy（）方法，您可以按如下方式存储按钮的状态：

SharedPreferences prefs = getSharedPreferences(
                           "file_name", Context.MODE_PRIVATE);
Editor editor = prefs.edit();
editor.putBoolean("BUTTON_SELECTED", true);
editor.commit();

您可以在活动的onCreate（）方法中合理地保持同一按钮的状态，如下所示：

SharedPreferences prefs = getSharedPreferences(
                               "file_name", Context.MODE_PRIVATE);
boolean isButtonSelected = prefs.getBoolean("BUTTON_SELECTED", false);

然后您可以设置该特定按钮的最后状态;

在后退按钮，应用程序关闭/重新启动等时检查开关按钮

1 个答案: