我有一个错误，我认为是由于列出重用对象的方式。我有一个下载按钮列表，下载时会显示进度读数。更新代码在后台线程中。
当我滚动列表时，显示进度的按钮会跳转到其他列表元素。我怎样才能阻止这个？很难想象，所以我做了一个视频：
http://www.youtube.com/watch?v=EiT2YWb2Prs&feature=youtu.be
顺便说一句，该视频是由我的客户制作的，因此请忽略“三星错误”位。我是开发者...
这是代码：
公共类 VideosActivity 扩展 Activity {
ListView video_list;
CustomList2 adapter;
File storage_dir;
String s3_bucket = "xx";
String s3_dir = "android/vol1/"; //the directory after the boucket that the files are stored in (do not add first slash)
Handler handler = new Handler(); //'tunnel' through whci other threads communicate with main thread
ArrayList<String> arr_videos = new ArrayList<String>();
ArrayList<String> arr_sdcardvideos = new ArrayList<String>();
int images[] = {R.drawable.kr115,R.drawable.kr200,R.drawable.kr201,R.drawable.kr202,R.drawable.kr203,R.drawable.kr205,R.drawable.kr206,R.drawable.kr207,R.drawable.kr208,R.drawable.kr209,R.drawable.kr210,R.drawable.kr211,R.drawable.kr212,R.drawable.kr213,R.drawable.kr213,R.drawable.kr214,R.drawable.kr215,R.drawable.kr216,R.drawable.kr210,R.drawable.kr211,R.drawable.kr212,R.drawable.kr213};
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
storage_dir = getApplicationContext().getExternalFilesDir(null); //private to app, removed with uninstall
adapter = new CustomList2(this, R.layout.customlist, arr_videos);
video_list = (ListView)findViewById(R.id.list);
video_list.setAdapter(adapter); //set adapter that specifies list contents
ensureStorageDirExists( storage_dir ); //make sure storage dir exists
set_sdcard_video_data(); //store vids arleady on card
set_video_data(); //store vid dat in array
if(!have_connection())
{
Toast.makeText(this, "No Internet connection", Toast.LENGTH_LONG).show();
return;
}
}
protected void ensureStorageDirExists( File dir )
{
if (!dir.exists())
{
dir.mkdirs();
}
}
public void set_sdcard_video_data()
{
arr_sdcardvideos.clear();
for(File f:storage_dir.listFiles())
{
arr_sdcardvideos.add( f.getName() );
}
}
public void set_video_data()
{
arr_videos.add("02Posture_and_Walk.m4v");
arr_videos.add("03Embrace_Connection_and_Musicality.m4v");
arr_videos.add("04Left_Turning_Check_Step.m4v");
arr_videos.add("05Basic_Right_Turn.m4v");
arr_videos.add("06Ocho_Cortado.m4v");
arr_videos.add("07Media_Vuelta.m4v");
arr_videos.add("08The_Cross.m4v");
arr_videos.add("09Front_Ochos.m4v");
arr_videos.add("10The_Cross_in_Cross_System.m4v");
arr_videos.add("11Back_Ochos.m4v");
arr_videos.add("12Molinete_Giro.m4v");
arr_videos.add("13Right_Turn.m4v");
arr_videos.add("14Combining_All_the_Elements_1.m4v");
arr_videos.add("15Combining_All_the_Elements_2.m4v");
arr_videos.add("16Combining_All_the_Elements_3.m4v");
arr_videos.add("17Combining_All_the_Elements_4.m4v");
arr_videos.add("18Combining_All_the_Elements_5.m4v");
arr_videos.add("19Combining_All_the_Elements_6.m4v");
arr_videos.add("20Demo_Using_All_the_Elements.m4v");
arr_videos.add("36Etiquette.m4v");
}
public SharedPreferences stored_vals()
{
return PreferenceManager.getDefaultSharedPreferences(this);
}
public boolean have_connection()
{
ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
if(cm.getActiveNetworkInfo()!=null && cm.getActiveNetworkInfo().isConnected() && cm.getActiveNetworkInfo().isAvailable())
{
return true;
}
else
{
return false;
}
}
public void download_video(int position, View btn)
{
}
public class CustomList2 extends ArrayAdapter<String>
{
View view;
int position;
Button btn;
public CustomList2(Context context, int layout_id, ArrayList<String> objects)
{
super(context, layout_id, objects);
}
@Override
public View getView(final int position, View convertView, ViewGroup view_group)
{
set_view(convertView);
this.position = position;
TextView text_view = (TextView) view.findViewById(R.id.name);
ImageView image = (ImageView) view.findViewById(R.id.img);
btn = (Button) view.findViewById(R.id.play);
prepare_btn();
text_view.setText( list_text() );
image.setImageResource(images[position]);
return view;
}
public String list_text()
{
String s = arr_videos.get( position ).replace("_", " ").replace(".m4v", "");
s = s.substring(2, s.length());
return s;
}
public void set_view(View convertView)
{
if(convertView == null)
{
LayoutInflater inflater = getLayoutInflater();
view = inflater.inflate(R.layout.customlist, null);
}
else
{
view = convertView;
}
}
public Boolean is_downloaded()
{
return arr_sdcardvideos.contains(arr_videos.get(position));
}
public void prepare_btn()
{
btn.setTag((Integer) position);
if(is_downloaded() == true)
{
btn.setText("Play ");
btn.setEnabled(true);
btn.setOnClickListener( new OnClickListener()
{
public void onClick(View btn)
{
int position = (Integer) btn.getTag();
Intent i = new Intent(VideosActivity.this, PlayVideoActivity.class);
String video_path = storage_dir + "/" + arr_videos.get(position);
Log.v("video_path", video_path);
i.putExtra("video_path", video_path);
startActivity(i);
}
});
}
else
{
btn.setText("Download ");
btn.setOnClickListener( new OnClickListener()
{
public void onClick(View btn)
{
int position = (Integer) btn.getTag();
btn.setEnabled(false);
//download_video( position, btn );
Download d = new Download();
d.start(position, (Button) btn);
}
});
}
}
}
public class Download
{
File new_video_file;
Button btn; //the progress meter needs to know what button called this. set via setter method below.
int position;
com.amazonaws.services.s3.transfer.Download download;
protected void start(int position, Button btn)
{
this.btn = (Button) btn;
this.position = position;
this.new_video_file = new File(storage_dir, arr_videos.get(position)); //local file to be writtent to
AWSCredentials credentials = new BasicAWSCredentials("xx", "xx" );
TransferManager tx = new TransferManager(credentials);
this.download = tx.download(s3_bucket, s3_dir + arr_videos.get(position), new_video_file);
download.addProgressListener(new ProgressListener()
{
public void progressChanged(final ProgressEvent pe)
{
handler.post( new Runnable()
{
@Override
public void run()
{
if ( pe.getEventCode() == ProgressEvent.COMPLETED_EVENT_CODE )
{
Download.this.onComplete();
}
else
{
Download.this.onProgressUpdate();
}
}
});
}
});
}
//protected void onProgressUpdate(Double progress)
protected void onProgressUpdate()
{
Double progress = this.download.getProgress().getPercentTransfered();
String percent = progress.intValue() + "%";
Log.v("runnable", percent);
btn.setText(percent);
Log.v("dev", progress + "");
}
protected void onComplete()
{
Log.v("dev", "download complete!!!");
set_sdcard_video_data();
adapter.notifyDataSetChanged();
// this.download.abort();
}
}
}