java - Android 音乐应用程序 "has stopped"无缘无故

Question

我正在尝试为 android 创建基本的音乐播放器。对我来说一切似乎都很好，但是当我试图在我的手机上运行应用程序时。它说它停止了。我无法解决那个问题。感谢您的任何帮助。我试图在应用程序停止时查看“Logcat”，但这对我来说似乎很正常。

MainActivity.java

    public class MainActivity extends ListActivity {
        private static final int UPDATE_FREQUENCY = 500;
        private static final int STEP_VALUE = 4000;

        private MediaCursorAdapter mediaAdapter = null;
        private TextView selectedFile= null;
        private SeekBar seekbar = null;
        private MediaPlayer player = null;
        private ImageButton playButton = null;
        private ImageButton previousButton = null;
        private  ImageButton nextButton = null;

        private boolean isStarted = true;
        private  String currentFile = "";
        private boolean isMovingseekBar = false;

        private final Handler handler = new Handler();

        private final Runnable updatePositionRunnable = new Runnable() {
            public  void run() {
                updatePosition();

            }
        };

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

            selectedFile = (TextView) findViewById(R.id.selectedfile);
            seekbar = (SeekBar) findViewById(R.id.seekbar);
            playButton = (ImageButton) findViewById(R.id.play);
            previousButton = (ImageButton) findViewById(R.id.previous);
            nextButton = (ImageButton) findViewById(R.id.next);

            player = new MediaPlayer();

            player.setOnCompletionListener(onCompletion);
            player.setOnErrorListener(onError);
            seekbar.setOnSeekBarChangeListener(seekBarChanged);
            Cursor cursor = getContentResolver().query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, null, null, null, null);

            if (null != cursor) {
                cursor.moveToFirst();

                mediaAdapter = new MediaCursorAdapter(this, R.layout.listitem, cursor);
                setListAdapter(mediaAdapter);
                playButton.setOnClickListener(onButtonClick);
                nextButton.setOnClickListener(onButtonClick);
                previousButton.setOnClickListener(onButtonClick);
            }
        }
        @Override
        protected  void onListItemClick(ListView list, View view, int position, long id) {
            super.onListItemClick(list, view, position, id);
            currentFile = (String) view.getTag();
            startPlay(currentFile);
        }
        @Override
        protected void onDestroy(){
            super.onDestroy();

            handler.removeCallbacks(updatePositionRunnable);
            player.stop();
            player.reset();
            player.release();

            player = null;
        }
        private  void startPlay(String file) {
//        Log.i("Selected: ",file);

            selectedFile.setText(file);
            seekbar.setProgress(0);

            player.stop();
            player.reset();

            try {
                player.setDataSource(file);
                player.prepare();
                player.start();
            } catch (IllegalArgumentException e){
                e.printStackTrace();
            } catch (IllegalStateException e){
                e.printStackTrace();
            } catch (IOException e){
                e.printStackTrace();
            }

            seekbar.setMax(player.getDuration());
            playButton.setImageResource(android.R.drawable.ic_media_pause);

            updatePosition();

            isStarted = true;

        }

        private void stopPlay() {
            player.stop();
            player.reset();
            playButton.setImageResource(android.R.drawable.ic_media_play);
            handler.removeCallbacks(updatePositionRunnable);
            seekbar.setProgress(0);

            isStarted = false;
        }
        private void updatePosition() {
            handler.removeCallbacks(updatePositionRunnable);

//        seekbar.setSecondaryProgressTintMode(player.getCurrentPosition());
            handler.postDelayed(updatePositionRunnable, UPDATE_FREQUENCY);
        }


        private class MediaCursorAdapter extends SimpleCursorAdapter {

            public MediaCursorAdapter(Context context, int layout, Cursor c){
                super(context, layout,c,
                        new String[] {MediaStore.MediaColumns.DISPLAY_NAME, MediaStore.MediaColumns.TITLE, MediaStore.Audio.AudioColumns.DURATION},
                        new int[] {R.id.displayname, R.id.title,R.id.duration});
            }

            @Override
            public void bindView(View view,Context context, Cursor cursor) {
                TextView title = (TextView) view.findViewById(R.id.title);
                TextView name = (TextView) view.findViewById(R.id.displayname);
                TextView duration = (TextView) view.findViewById(R.id.duration);

                name.setText(cursor.getString(
                        cursor.getColumnIndex(MediaStore.MediaColumns.DISPLAY_NAME)));

                title.setText(cursor.getString(
                        cursor.getColumnIndex(MediaStore.MediaColumns.TITLE)));

//            long durationInMs = Long.parseLong(cursor.getString(
//                    cursor.getColumnIndex(MediaStore.Audio.AudioColumns.DURATION)));
//
//            double durationInMin = ((double) durationInMs / 1000.0) / 60.0;

//            durationInMin = new BigDecimal(Double.toString(durationInMin)).setScale(2, BigDecimal.ROUND_UP).doubleValue();
//
//            duration.setText("" + durationInMin);
//
                view.setTag(cursor.getString(cursor.getColumnIndex(MediaStore.MediaColumns.DATA)));
            }
            @Override
            public View newView(Context context, Cursor cursor, ViewGroup parent) {
                LayoutInflater inflater = LayoutInflater.from(context);
                View v = inflater.inflate(R.layout.listitem, parent, false);

                bindView(v, context, cursor);

                return v;
            }
        }



        private View.OnClickListener onButtonClick  = new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                switch (v.getId()) {
                    case R.id.play: {
                        if (player.isPlaying()) {
                            handler.removeCallbacks(updatePositionRunnable);
                            player.pause();
                            playButton.setImageResource(android.R.drawable.ic_media_play);
                        } else {
                            if (isStarted) {
                                player.start();
                                playButton.setImageResource(android.R.drawable.ic_media_pause);
                                updatePosition();
                            } else {
                                startPlay(currentFile);
                            }
                        }
                        break;
                    }
                    case R.id.next: {
                        int seekto = player.getCurrentPosition() + STEP_VALUE;

                        if (seekto > player.getDuration())
                            seekto = player.getDuration();
                        player.start();

                        break;
                    }
                    case R.id.previous: {
                        int seekto = player.getCurrentPosition() - STEP_VALUE;

                        if (seekto < 0)
                            seekto = 0;

                        player.pause();
                        player.seekTo(seekto);
                        player.start();

                        break;

                    }
                }
            }
        };
        private MediaPlayer.OnCompletionListener onCompletion = new MediaPlayer.OnCompletionListener() {

            @Override
            public void onCompletion(MediaPlayer mp) {
                stopPlay();
            }
        };

        private MediaPlayer.OnErrorListener onError = new MediaPlayer.OnErrorListener() {

            @Override
            public boolean onError(MediaPlayer mp, int what, int extra) {

                return false;
            }
        };


        private SeekBar.OnSeekBarChangeListener seekBarChanged = new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {
                isMovingseekBar = false;
            }

            @Override
            public void onProgressChanged(SeekBar seekBar, int progress, boolean fomUser) {
                if (isMovingseekBar) {
                    player.seekTo(progress);
                    Log.i("OnSeekBarChangeListener", "onProgressChange");
                }
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {
                isMovingseekBar = true;
            }
        };

    }

Logcat“警告”

04-06 00:44:39.587 10679-10679/? E/Zygote: isWhitelistProcess - Process is Whitelisted 04-06 00:44:39.588 10679-10679/? E/libpersona: scanKnoxPersonas Couldn't open the File - /data/system/users/0/personalist.xml - No such file or directory

已更新现在这个弹出窗口

04-06 00:49:32.764 3130-3130/? E/audit: type=1400 audit(1522968572.746:16192): avc:  denied  { read } for  pid=12132 comm="Bg_Shared3" name="boot_id" dev="proc" ino=12061920 scontext=u:r:untrusted_app_25:s0:c512,c768 tcontext=u:object_r:proc:s0 tclass=file permissive=0 SEPF_SM-N950F_8.0.0_0002 audit_filtered
04-06 00:49:32.767 11925-12132/? E/msgr.BootIdReader: Error reading boot_id from procfs
    java.io.FileNotFoundException: /proc/sys/kernel/random/boot_id (Permission denied)
        at java.io.FileInputStream.open0(Native Method)
        at java.io.FileInputStream.open(FileInputStream.java:200)
        at java.io.FileInputStream.<init>(FileInputStream.java:150)
        at java.io.FileInputStream.<init>(FileInputStream.java:103)
        at java.io.FileReader.<init>(FileReader.java:58)
        at X.17G.a(:240349)
        at X.1ex.a(Unknown Source:680)
        at X.0I4.A(Unknown Source:26)
        at X.0IZ.a(:51612)
        at X.0IZ.b(:51631)
        at X.2FF.d(:450319)
        at X.2FF.b(:450310)
        at X.2FF.a(:450272)
        at X.2FD.init(:450217)
        at X.0RK.run(:69037)
        at X.0Mi.run(:60705)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:457)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:457)
        at X.0Nz.run(:62781)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:457)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at X.0LN.run(:57215)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1162)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:636)
        at X.0O8.run(:63173)
        at java.lang.Thread.run(Thread.java:764)
04-06 00:49:32.769 3130-3130/? E/audit: type=1300 audit(1522968572.746:16192): arch=40000028 syscall=322 per=8 success=no exit=-13 a0=ffffff9c a1=dbbf9200 a2=20000 a3=0 items=0 ppid=3787 pid=12132 auid=4294967295 uid=10271 gid=10271 euid=10271 suid=10271 fsuid=10271 egid=10271 sgid=10271 fsgid=10271 tty=(none) ses=4294967295 comm="Bg_Shared3" exe="/system/bin/app_process32" subj=u:r:untrusted_app_25:s0:c512,c768 key=(null)
    type=1327 audit(1522968572.746:16192): proctitle="com.facebook.orca"

另一个更新:问题似乎出在我称为“listitem”的 XML 文件中，正如它所说，它列出了手机中的 MP3 文件。 Wihtout 那个文件(及其实现，如持续时间、显示名称)它确实“工作”(打开)

“列表项”

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView android:id="@+id/displayname"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:ellipsize="end"
        android:textSize="18dip"
        android:textStyle="bold" />

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <TextView
            android:id="@+id/title"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1.0"
            android:ellipsize="end"
            android:singleLine="true"
            android:textSize="15dip" />
        <TextView
            android:id="@+id/duration"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:ellipsize="end"
            android:gravity="right"
            android:singleLine="true"
            android:textSize="15dip" />


    </LinearLayout>

</LinearLayout>

Answer 1

如果你想从存储中读取你需要这个权限

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

写作

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

如果你想读和写，把它们都加上