我的应用中有一个列表视图，如果我点击列表中的一个项目，它会突出显示。然后，如果我单击另一个项目，该突出显示将切换到该项目。但是如果在选择项目后滚动列表然后从列表的另一部分中选择另一个项目，则它们都会保持突出显示。但如果我不滚动屏幕则不行。是什么造成的？以及如何处理它？</ p>
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);
}
}
答案 0 :(得分：3)
此问题的原因是Android回收ListView项目的方式。防止这样的事情的方法是手动保存点击该项目。在适配器中，您可以创建一个包含当前所选项目的变量。在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
}
答案 1 :(得分：0)
您好，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，您可以在活动中创建此适配器：
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 = Array包含文本项的字符串。 imagesId =带有的数组 图片在您的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 set adapter：
ListView listTest = (ListView) findViewById(R.id.listTest);
listTest .setAdapter(new MyAdapter());
如果您需要最佳示例，请转到导入示例 - ＆gt;选择你的版本 y转到List，这里是列表多选的例子。