使用SharedPreferences填充ListView

Question

我有一个应用程序可以保存youtube搜索的查询标记列表。用户在Main活动的editText中输入搜索，当用户按下保存按钮时，该搜索将保存在ListActivity的ListView中。问题是当我关闭应用程序并再次打开它时，保存的搜索消失了。我使用SharedPreferences保存搜索，但无法让我的ListView用保存的搜索填充它。有人可以给我一些关于如何使用SharedPreferences检索保存在ListView中的数据的方向吗？我的代码如下。

//This is the Main Activity
public class Main extends Activity {


    Button save;
    EditText text;


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



        final WebView browser = (WebView) findViewById(R.id.webview);
        browser.setWebViewClient(new MyBrowser());
        browser.setBackgroundColor(Color.TRANSPARENT);

        Button buttonSearch = (Button) findViewById(R.id.searchButton);
        Button buttonSave = (Button) findViewById(R.id.saveButton);
        Button buttonFav = (Button) findViewById(R.id.favButton);
        Button buttonCancel = (Button) findViewById(R.id.cancelButton);
        final EditText textItem = (EditText) findViewById(R.id.queryEditText);
        final ArrayList<String> arr = new ArrayList<String>();

        buttonSave.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                String item = textItem.getText().toString();



                arr.add(item);
                //Add saved search to shared preferences
                SharedPreferences sharedPref = getSharedPreferences("favs", 0);
                SharedPreferences.Editor editor = sharedPref.edit();
                editor.putString("fav", item);
                editor.commit();

                textItem.setText("");






                InputMethodManager inputManager = (InputMethodManager)
                        getSystemService(Context.INPUT_METHOD_SERVICE);

                inputManager.hideSoftInputFromWindow(getCurrentFocus().getWindowToken(),
                        InputMethodManager.HIDE_NOT_ALWAYS);
            }
        });

        buttonSearch.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v) {
                String sQuery = textItem.getText().toString();
                browser.getSettings().setLoadsImagesAutomatically(true);
                browser.getSettings().setJavaScriptEnabled(true);
                browser.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);

                browser.loadUrl(getString(R.string.searchURL) + sQuery);
                browser.setVisibility(v.VISIBLE);




                InputMethodManager inputManager = (InputMethodManager)
                        getSystemService(Context.INPUT_METHOD_SERVICE);

                inputManager.hideSoftInputFromWindow(getCurrentFocus().getWindowToken(),
                        InputMethodManager.HIDE_NOT_ALWAYS);
            }
        });


        buttonFav.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v) {




                Intent intent = new Intent(getApplicationContext(), ListActivity.class);



                intent.putExtra("array_list", arr);
                textItem.setText("");
                startActivity(intent);
            }
        });


        buttonCancel.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                browser.setVisibility(v.GONE);
                textItem.setText("");
            }
        });

    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    private class MyBrowser extends WebViewClient {
        @Override
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            view.loadUrl(url);
            return true;
        }
    }
}

ListActivity

    import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.net.Uri;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;

import java.util.ArrayList;


public class ListActivity extends Activity {

    EditText searchTxt;
    ListView lv;
    StringArrayAdapter ad;


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

        Button backButton = (Button) findViewById(R.id.backButton);



        searchTxt = (EditText) findViewById(R.id.searchText);

        Bundle b = getIntent().getExtras();

        SharedPreferences sharedPref = getSharedPreferences("array_list", 0);
        String listItem = sharedPref.getString("fav", "");

         lv = (ListView) findViewById(R.id.listViewItem);

        final ArrayList<String> arr = (ArrayList<String>) b.getStringArrayList("array_list");

        lv.setTextFilterEnabled(true);


        ad = new StringArrayAdapter(arr, this);
        lv.setAdapter(ad);


        lv.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
            @Override
            public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
                ad.items.remove(position);
                ad.notifyDataSetChanged();
                ad.notifyDataSetInvalidated();

                return false;
            }
        });






        searchTxt.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {

            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {
                ad.getFilter().filter(s.toString());
            }

            @Override
            public void afterTextChanged(Editable s) {

            }
        });
        lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

                String query = lv.getItemAtPosition(position).toString();
                String urlString = getString(R.string.searchURL) + query;

                Intent getURL = new Intent(Intent.ACTION_VIEW, Uri.parse(urlString));

                startActivity(getURL);




            }


        });

        backButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent i = new Intent(getApplicationContext(), Main.class);
                startActivity(i);
            }
        });


    }




    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.list, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

StringArrayAdapter

    import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Filter;
import android.widget.Filterable;
import android.widget.TextView;

import java.util.ArrayList;

/**
 * Created by tobyblanchard on 11/14/14.
 */
public class StringArrayAdapter extends BaseAdapter implements Filterable {

    ArrayList<String> items;
    Context ctxt;
    LayoutInflater myInflater;


    public StringArrayAdapter(ArrayList<String> arr, Context c){
        items = arr;
        ctxt = c;
        myInflater = (LayoutInflater)c.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

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

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

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        if (convertView == null)
            convertView = myInflater.inflate(android.R.layout.simple_list_item_activated_1, parent, false);
        TextView name = (TextView)convertView.findViewById(android.R.id.text1);
        name.setText(items.get(position));

        return convertView;
    }




    @Override
    public Filter getFilter() {
        Filter filter = new Filter() {

            @Override
            protected FilterResults performFiltering(CharSequence constraint) {
                FilterResults results = new FilterResults();
                ArrayList<String> FilteredArraylist = new ArrayList<String>();

                if (items == null){
                    items = new ArrayList<String>(items);
                }
                if (constraint == null || constraint.length() == 0) {

                    // set the Original result to return
                    results.count = items.size();
                    results.values = items;
                } else {
                    constraint = constraint.toString().toLowerCase();
                    for (int i = 0; i < items.size(); i++) {
                        String data = items.get(i);
                        if (data.toLowerCase().startsWith(constraint.toString())) {
                            FilteredArraylist.add(data);
                        }
                    }
                    // set the Filtered result to return
                    results.count = FilteredArraylist.size();
                    results.values = FilteredArraylist;
                }
                return results;
            }

            @Override
            protected void publishResults(CharSequence constraint, FilterResults results) {
                items = (ArrayList<String>) results.values; // has the filtered values
                notifyDataSetChanged();
            }
        };




        return filter;
    }


}