我正在使用音频播放器教程androidhive.info https://www.androidhive.info/2012/03/android-building-audio-player-tutorial/在 SongsManager.java 中，我尝试将持续时间转换为分钟和秒。我已经设法做到了，但我不断得到NumberFormatException我不知道如何处理。部分代码在这里：
public ArrayList<HashMap<String, String>> getPlayList(Context c) {
String selectionMimeType = MediaStore.Files.FileColumns.MIME_TYPE + "=?";
/*use content provider to get beginning of database query that queries for all audio by display name, path
and mimtype which i dont use but got it incase you want to scan for mp3 files only you can compare with RFC mimetype for mp3's
*/
final Cursor mCursor = c.getContentResolver().query(
MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,
new String[] { MediaStore.Audio.Media.TITLE, MediaStore.Audio.Media.DATA,MediaStore.Audio.Media.MIME_TYPE,MediaStore.Audio.Media.ARTIST,MediaStore.Audio.Media.ALBUM,MediaStore.Audio.Media.DURATION }, null, null,
"LOWER(" + MediaStore.Audio.Media.TITLE + ") ASC");
String songs_name = "";
String mAudioPath = "";
String songs_artist = "";
String songs_album = "";
String songs_duration = "";
/* run through all the columns we got back and save the data we need into the arraylist for our listview*/
if (mCursor.moveToFirst()) {
do {
String file_type = mCursor.getString(mCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.MIME_TYPE));
songs_name = mCursor.getString(mCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.TITLE));
mAudioPath = mCursor.getString(mCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DATA));
songs_artist = mCursor.getString(mCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.ARTIST));
songs_album = mCursor.getString(mCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.ALBUM));
songs_duration = mCursor.getString(mCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DURATION));
HashMap<String, String> song = new HashMap<String, String>();
songs_duration = setCorrectDuration(songs_duration);
song.put("songTitle", songs_name);
song.put("songPath", mAudioPath);
song.put("songArtist", songs_artist);
song.put("songAlbum", songs_album);
song.put("songDuration", songs_duration);
songsList.add(song);
} while (mCursor.moveToNext());
}
mCursor.close(); //cursor has been consumed so close it
return songsList;
}
private String setCorrectDuration(String songs_duration) {
// TODO Auto-generated method stub
if(Integer.valueOf(songs_duration) != null) {
int time = Integer.valueOf(songs_duration);
int seconds = time/1000;
int minutes = seconds/60;
seconds = seconds % 60;
if(seconds<10) {
songs_duration = String.valueOf(minutes) + ":0" + String.valueOf(seconds);
} else {
songs_duration = String.valueOf(minutes) + ":" + String.valueOf(seconds);
}
return songs_duration;
}
return null;
}
这是 LogCat 的一部分：
10-28 23:39:13.047: W/dalvikvm(30524): threadid=1: 线程退出
未捕获的异常（组=0x422f2700）10-28 23:39:13.047：
E/AndroidRuntime(30524): 致命异常: main 10-28 23:39:13.047:
E/AndroidRuntime(30524): java.lang.RuntimeException: 无法启动
活动
组件信息{com.vany.vansmusic/com.vany.vansmusic.AndroidBuildingMusicPlayerActivity}：
java.lang.NumberFormatException：无效的 int：“null”
10-28 23:39:13.047: E/AndroidRuntime(30524): 在
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2305)
10-28 23:39:13.047: E/AndroidRuntime(30524): 在
android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2359)
10-28 23:39:13.047: E/AndroidRuntime(30524): 在
android.app.ActivityThread.access$700(ActivityThread.java:165) 10-28
23:39:13.047: E/AndroidRuntime(30524): 在
android.app.ActivityThread$H.handleMessage(ActivityThread.java:1326)
我将非常感谢您的帮助。
UPDATE:为遇到相同或类似问题的任何人解决了这个问题：
if (mCursor.moveToFirst()) {
do {
String file_type = mCursor.getString(mCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.MIME_TYPE));
songs_name = mCursor.getString(mCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.TITLE));
mAudioPath = mCursor.getString(mCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DATA));
songs_artist = mCursor.getString(mCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.ARTIST));
songs_album = mCursor.getString(mCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.ALBUM));
songs_duration = mCursor.getString(mCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DURATION));
HashMap<String, String> song = new HashMap<String, String>();
if(String.valueOf(songs_duration) != null) {
try {
Long time = Long.valueOf(songs_duration);
long seconds = time/1000;
long minutes = seconds/60;
seconds = seconds % 60;
if(seconds<10) {
String csongs_duration = String.valueOf(minutes) + ":0" + String.valueOf(seconds);
song.put("songDuration", csongs_duration);
} else {
String ccsongs_duration = String.valueOf(minutes) + ":" + String.valueOf(seconds);
song.put("songDuration", ccsongs_duration);
}
} catch(NumberFormatException e) {
song.put("songDuration", songs_duration);
}
} else {
String nothing = "0";
song.put("songDuration", nothing);
}
song.put("songTitle", songs_name);
song.put("songPath", mAudioPath);
song.put("songArtist", songs_artist);
song.put("songAlbum", songs_album);
songsList.add(song);
} while (mCursor.moveToNext());
}
mCursor.close(); //cursor has been consumed so close it
return songsList;
