ListView 项目在滚动后保持突出显示

Question

我的应用程序中有一个列表视图，如果我单击列表中的一项，它会突出显示。然后，如果我单击另一个项目，则突出显示将转移到该项目。但是，如果在选择一个项目后滚动列表，然后从列表的另一部分选择另一个项目，它们都会保持突出显示。但如果我不滚动屏幕就不会。这是什么原因造成的？又该如何处理？

ListAdapter.java

package com.example.mp3;



import java.util.List;
import android.content.Context;
import android.content.SharedPreferences;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

public class ListAdapter extends BaseAdapter{

    private Context _context;
    private List<String> list;

    public  ListAdapter(Context _context,List<String> list)
    {
        this._context=_context;
        this.list=list;
    }
    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return list.size();
    }

    @Override
    public Object getItem(int arg0) {
        // TODO Auto-generated method stub
        return list.get(arg0);
    }

    @Override
    public long getItemId(int arg0) {
        // TODO Auto-generated method stub
        return arg0;
    }
     @Override

        public int getViewTypeCount() {

         return getCount();
        }

        @Override

        public int getItemViewType(int position) {

         return position;
        }


    @Override
    public View getView(int position, View convertView, ViewGroup viewGroup) {
        // TODO Auto-generated method stub

           View row = convertView;
            if (convertView == null) {
                LayoutInflater inflater = (LayoutInflater) _context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                row = inflater.inflate(R.layout.simplerow, viewGroup, false);
            }


            TextView textView = (TextView) row.findViewById(R.id.rowTextView);
            textView.setText(list.get(position).toString());



        return row;
    }



}

MainActivity.java

package com.example.mp3;


import java.io.File;
import java.io.IOException;
import java.util.ArrayList;

import android.app.ActionBar;
import android.app.Activity;
import android.app.SearchManager;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.preference.PreferenceManager;

import android.support.v4.view.MenuItemCompat;
import android.support.v4.view.MenuItemCompat.OnActionExpandListener;
import android.text.Html;
import android.util.Log;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;

import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.ListView;
import android.widget.SearchView;
import android.widget.TextView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.Toast;


public class MainActivity extends Activity implements View.OnClickListener, OnCompletionListener {

    ListView list;
    ArrayAdapter<String> adapter ;
    ArrayList<String> listTest;
     ArrayList<String> listSoundNames;
    ImageButton play,stop,back,next;
    String songpath,song,title;
    int index,current_position;
    File[] listFile;
    SharedPreferences sharedPref;
    MediaPlayer mp,mp2;
    ActionBar bar;
    private Boolean state=false;
    private static int save = -1;
    int count=0;
    private static final String TAG = MainActivity.class.getSimpleName();
    private Context _context = this;


    @Override
    protected void onCreate(Bundle savedInstanceState) {



        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        sharedPref = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
        song = sharedPref.getString("songname", "name");

        mp=new MediaPlayer();
        mp2 = new MediaPlayer();

        mp.setOnCompletionListener(this);


        list = (ListView)findViewById(R.id.list);
        //list.setChoiceMode(ListView.CHOICE_MODE_SINGLE); 

        _context=this;





        listTest = new ArrayList<String>( );
        listSoundNames=new ArrayList<String>();

        play = (ImageButton)findViewById(R.id.play);
        back = (ImageButton)findViewById(R.id.prev);
        next = (ImageButton)findViewById(R.id.next);

        //adding listeners
        play.setOnClickListener(this);
        back.setOnClickListener(this);
        next.setOnClickListener(this);


        //action bar controls
        bar = getActionBar();
        bar.setBackgroundDrawable(new ColorDrawable(Color.parseColor("#DF0174")));
        //bar.setIcon(new ColorDrawable(getResources().getColor(android.R.color.transparent))); 

        EditText editText = new EditText(getApplicationContext());
        getActionBar().setCustomView(editText);


        //bar.setDisplayShowTitleEnabled(true);
        //bar.setDisplayHomeAsUpEnabled(true);

        Scanner("/sdcard/");///storage path


        /////////////////////////////////////////////////////////////////////////////////////////////////////////////////
        /////////////////////////////////////*Adding listener to songs*//////////////////////////////////////////////////
        /////////////////////////////////////////////////////////////////////////////////////////////////////////////////

        if(listTest.size() != 0)
        {
            //listAdapter = new ArrayAdapter<String> (MainActivity.this,R.layout.simplerow, listSoundNames);

            ListAdapter listAdapter=new ListAdapter(_context,listSoundNames);
            list.setAdapter(listAdapter);
            list.setOnItemClickListener(new OnItemClickListener() 
            {
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) 
            {
                ///////////////////changing list item background on click///////////////////

                list.clearChoices();
                //list.setSelection(position);
                view.setSelected(true);  ///////////////////PROBLEM/////////////

                for(int a = 0; a < parent.getChildCount(); a++)
                {

                    parent.getChildAt(a).setBackgroundColor(Color.BLACK);


                }


                view.setBackgroundColor(Color.RED);


                ////////////////////////////////////////////////////////////////////////////
                //accessing song path
                String selected = listTest.get(position);
                list.setItemChecked(position, true);//

                //accessing the song name
                String name = (String) ((TextView) view).getText();
                title = name;
                //bar.setTitle(title);
                //Log.e(TAG, name);

                Toast.makeText(getApplicationContext(), name, Toast.LENGTH_SHORT).show();
                try{
                    mp.reset();
                    mp.setDataSource(listTest.get(position));//source
                    mp.prepare();
                    mp.start();
                    index = position;
                    play.setImageResource(R.drawable.pause);
                    }
                catch(Exception e){e.printStackTrace();}



            }


            });




            }

        }



        ////////////////////////////////////////////////////////////////////////////////////////////
        //////////////////////////////////*Songs added here to list*////////////////////////////////
        ////////////////////////////////////////////////////////////////////////////////////////////

        private void Scanner(String path) {
            // TODO Auto-generated method stub
            {
                try 
                {
                        File fl = new File(path);
                        File[] listOfFiles = fl.listFiles();              

                        for (File listOfFile : listOfFiles)
                         {
                            String s = listOfFile.getName();

                            if(s.endsWith(".mp3"))
                            {

                            songpath = listOfFile.getPath();
                            listTest.add(songpath);//adding song names to list
                            //listTest.toString().replaceFirst(songpath, s);



                            // store file name in listSoundNames
                            int pos = s.lastIndexOf(".");
                            if (pos > 0)
                            {
                                song = s.substring(0, pos);
                            }
                            listSoundNames.add(song);

                            }


                            /////////////////////////////////
                            File f = new File(path+s+"/");
                            if (f.exists() && f.isDirectory()) {
                            Scanner(path+s+"/");
                            }
                            ////////////////////////////////


                        }



                }
            catch (Exception e) { }
            }

            }








    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub

        if (v.equals(play))
        {
            if(mp.isPlaying())
            {
                mp.pause();
                Toast.makeText(MainActivity.this, "paused", Toast.LENGTH_SHORT).show();
                //change in button image//
                play.setImageResource(R.drawable.play);

            }
            else
            {
                mp.start();
                Toast.makeText(MainActivity.this, "started", Toast.LENGTH_SHORT).show();
                //change in button image//
                play.setImageResource(R.drawable.pause);
                //
            }
        }


            if (v.equals(back))
            {
                mp.stop();
                mp.reset();
                //bar.setTitle(song);
                if(index!=0)
                {
                index = index -1;
                }
                else
                {
                    index = (list.getAdapter().getCount()-1)-1;

                }

                Uri uri = Uri.parse(listTest.get(index).toString());//getting the path of next song
                try {


                    mp.setDataSource(getApplicationContext(), uri);//setting new data source 


                } catch (IllegalArgumentException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (SecurityException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (IllegalStateException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                    Toast.makeText(MainActivity.this, "ERROR", Toast.LENGTH_SHORT).show();///PROBLEM:MOVING HERE AFTER CLICKING NEXT BUTTON
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }

                try {
                    mp.prepare();
                } catch (IllegalStateException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }        
                mp.start();//PROBLEM: NOT PLAYING
                Toast.makeText(MainActivity.this, ""+uri, Toast.LENGTH_SHORT).show();

            }


            if (v.equals(next))
            {

                mp.stop();
                mp.reset();
                index = index +1;


                Uri uri = Uri.parse(listTest.get(index).toString());//getting the path of next song

                try {


                    mp.setDataSource(getApplicationContext(), uri);//setting new data source 


                } catch (IllegalArgumentException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (SecurityException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (IllegalStateException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                    Toast.makeText(MainActivity.this, "ERROR", Toast.LENGTH_SHORT).show();///PROBLEM:MOVING HERE AFTER CLICKING NEXT BUTTON
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }

                try {
                    mp.prepare();
                } catch (IllegalStateException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }        
                mp.start();//PROBLEM: NOT PLAYING
                Toast.makeText(MainActivity.this, ""+uri, Toast.LENGTH_SHORT).show();


            }


    }


    @Override
    public void onCompletion(MediaPlayer arg0) {
        // TODO Auto-generated method stub
        play.setImageResource(R.drawable.play);
    }

    /*@Override
    protected void onStop() {
        super.onStop();
        mp.stop();
        Toast.makeText(getApplicationContext(), "stopped", Toast.LENGTH_LONG).show();

    }*/

    //////////////////////////////////////////Search box/////////////////////////////////////////////////////

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.main, menu);



         SearchManager searchManager = (SearchManager) getSystemService(Context.SEARCH_SERVICE);
            SearchView searchView = (SearchView) menu.findItem(R.id.action_search).getActionView();

                searchView.setSearchableInfo(searchManager.getSearchableInfo(getComponentName()));
                searchView.setIconifiedByDefault(false);   
                searchView.setQueryHint(Html.fromHtml(("<font color = #ffffff>"+"Listen Now"+"</font>")));



            SearchView.OnQueryTextListener textChangeListener = new SearchView.OnQueryTextListener() 
            {
                @Override
                public boolean onQueryTextChange(String newText) 
                {
                    // this is your adapter that will be filtered
                    adapter.getFilter().filter(newText);

                    Toast.makeText(getApplicationContext(), "type"+newText, Toast.LENGTH_SHORT).show();
                    return true;
                }
                @Override
                public boolean onQueryTextSubmit(String query) 
                {
                    // this is your adapter that will be filtered
                    adapter.getFilter().filter(query);

                    //Toast.makeText(getApplicationContext(), query, Toast.LENGTH_SHORT).show();

                    try 
                    {
                            File fl = new File("/sdcard/");
                            File[] listOfFiles = fl.listFiles();  
                            String selectedPath="";

                            for (File listOfFile : listOfFiles)
                             {
                                String s = listOfFile.getName();

                                if(s.equalsIgnoreCase(query) && s.endsWith(".mp3"))
                                {

                                    selectedPath= listOfFile.getPath();//not receiving the path:PROBLEM:HOLDING THE POSITION FOR LIST ITEM


                                //listTest.add(songpath);//adding song names to list
                                //listTest.toString().replaceFirst(songpath, s);
                                Toast.makeText(getApplicationContext(), listOfFile.getPath(), Toast.LENGTH_SHORT).show();

                                /*mp.setDataSource(selectedPath);
                                mp.prepare();
                                mp.start();*/

                                }



                                /////////////////////////////////
                                File f = new File("/sdcard/"+s+"/");
                                if (f.exists() && f.isDirectory()) {
                                Scanner("/sdcard/"+s+"/");
                                }
                                ////////////////////////////////


                            }



                    }

                catch (Exception e) { }

                    return true;
                }
            };
            searchView.setOnQueryTextListener(textChangeListener);



            return super.onCreateOptionsMenu(menu);

    }


}

Answer 1

这个问题的原因是 Android 回收 ListView 项目的方式。防止这种情况发生的一种方法是手动保存单击的项目。在您的适配器中，您可以创建一个变量来保存当前选定的项目。在您的getView 中，您必须检查当前项目是否与所选项目相同。它看起来像这样：

if(row==currentSelected){ //set background color else{ //another background color -> this is important otherwise all listview items will have the same background color after swiping up and down }

Answer 2

你好，试试这个。

1- 您的活动从 ListActivity 扩展。 2-创建下一个适配器 对于您的列表，您可以在 Activity 中创建此适配器：

private class MyAdapter extends BaseAdapter {
@Override
public int getCount() {
    return items.length;
}

@Override
public String getItem(int position) {
    return items[position];
}

@Override
public long getItemId(int position) {
    return items[position].hashCode();
}



@Override
public View getView(int position, View convertView, ViewGroup container) {
    if (convertView == null) {
        convertView = getLayoutInflater().inflate(R.layout.list_item,             

container, false);
    }

        ((TextView) convertView.findViewById(android.R.id.text1))
                .setText(getItem(position));

        ImageView imageView = (ImageView)                                                                                 a     convertView.findViewById(R.id.imageView_Icon);
   imageView.setImageResource(imagesId[position]);

        return convertView;
    }
}

items = 包含文本项的数组字符串。 imagesId = 数组 图片在你的draweable中的ID。

在布局中创建下一个 list_item.xml

<com.Test.CheckableLinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingLeft="8dp"
    android:paddingRight="8dp"
    android:minHeight="?android:listPreferredItemHeight"
    android:gravity="center_vertical">


    <ImageView
        android:id="@+id/imageView_Icon"
        android:layout_height="60dp"
        android:contentDescription="IconDescription"
        android:layout_width="60dp" />

    <TextView android:id="@android:id/text1"
        android:duplicateParentState="true"
        android:layout_width="0dp"
        android:layout_weight="1"
        android:layout_height="wrap_content"
        android:textAppearance="?android:textAppearanceMedium"
        android:textColor="@color/hideable_text_color" />


    <ImageView android:src="@drawable/ic_hideable_item"
        android:duplicateParentState="true"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="16dp"
        android:id="@+id/imageView1" />

</com.Test.CheckableLinearLayout>

在 ListView 中的 Activity 集适配器中：

 ListView listTest = (ListView) findViewById(R.id.listTest);
        listTest .setAdapter(new MyAdapter());

如果您需要最佳示例，请转到 Import Sample -> 选择您的版本 y 转到列表，这里是列表多选的 excelente 示例。