FileNotFoundException 使用媒体播放器

Question

我已经尝试解决这个问题好几个小时了，但找不到合适的解决方案：我正在尝试播放媒体文件 (Mp3/Ogg)，但总是出现 FileNotFoundException（而且我确定它在那里 ;)）

这是我的尝试：

检查SD卡是否可用。

检查是否授予 reading/writing 权限。

Load/Play 歌曲.

if(isExternalStorageReadable() && isExternalStorageWritable())
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {
            Log.v("Permission","Readingpermission is granted");
        }
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {
            Log.v("Permission","Writingpermission is granted");
        }
        playSong(getExternalFilesDir(Environment.DIRECTORY_MUSIC).toString() + "/t1.mp3");

这部分代码目前有效。

但是一旦谈到 playSong(String) :

try {
        MediaPlayer mediaplayer = new MediaPlayer();
        mediaplayer.setDataSource(path);
        mediaplayer.prepare();
        mediaplayer.start();
    } catch (Exception e){
        Log.e("Mediaplayer", e.toString());
    }

程序在尝试设置数据源时崩溃并出现此异常：

E/Mediaplayer: java.io.FileNotFoundException: /storage/emulated/0/Android/data/OMSclient.omsgui/files/Music/t1.mp3

我错过了什么？我一头雾水

提前致谢。

编辑：

好的，我发现了以下问题：

如果我简单地执行

playSong("storage/17E5-1C14/Android/data/OMSclient.omsgui/files/Music/t1.ogg");

它工作正常，但如果我使用：

playSong("/storage/emulated/0/Android/data/OMSclient.omsgui/files/Music/t1.mp3");

或

播放歌曲("storage/emulated/0/Android/data/OMSclient.omsgui/files/Music/t1.mp3");

没有..

为什么？ ...

Answer 1

使用此代码，

 String filePath = "xx/xx/file.mp3";
 File file = new File(filePath);
 FileInputStream inputStream = new FileInputStream(file);
 mediaPlayer.setDataSource(inputStream.getFD());
 inputStream.close();

希望对您有所帮助！

Answer 2

我使用您提供的代码和以下属性创建了一个项目：

compileSdkVersion 26
minSdkVersion 19
targetSdkVersion 19

而且我发现 getExternalFilesDir(Environment.DIRECTORY_MUSIC).toString() returns 不同的值取决于模拟器的 Android 级别。

19 级奇巧 4.4 /storage/sdcard/Android/data/com.test.mediaplayerproblem/files/Music/test1.mp3

25 级牛轧糖 7.1.1 /storage/emulated/0/Android/data/com.test.mediaplayerproblem/files/Music/test1.mp3

这是我的有效代码，但请记住，我从原始资源中保存文件并在相同的地方播放它 activity 所以它总是在正确的位置。

MainActivity.java:

public class MainActivity extends AppCompatActivity
{
    private MediaPlayer mediaplayer;
    private String musicDirPath;
    private String filename = "/test1.mp3";

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

        musicDirPath = getExternalFilesDir(Environment.DIRECTORY_MUSIC).toString();
        TextView tv1 = findViewById(R.id.textView1);
        tv1.setText(musicDirPath + filename);
        Log.v("Mediaplayer", musicDirPath + filename);
    }

    public void playFile(View view) {
        if(isExternalStorageReadable() && isExternalStorageWritable())
            if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {
                Log.v("Permission","Readingpermission is granted");
            }
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {
            Log.v("Permission","Writingpermission is granted");
        }
        playSong(getExternalFilesDir(Environment.DIRECTORY_MUSIC).toString() + "/test1.mp3");
    }

    public void playSong(String path) {
        try {
            mediaplayer = new MediaPlayer();
            mediaplayer.setDataSource(path);
            mediaplayer.prepare();
            mediaplayer.start();
        } catch (Exception e){
            Log.e("Mediaplayer", e.toString());
        }
    }

    public void stopFile(View view) {
        if (mediaplayer != null) {
            try {
                mediaplayer.stop();
                mediaplayer.release();
                mediaplayer = null;
            } catch(Exception e) {
                Toast.makeText(this, e.getMessage(), Toast.LENGTH_LONG).show();
                e.printStackTrace();
            }
        }
    }

    public void saveFile(View view) {

        byte[] buffer = null;
        InputStream fis = getResources().openRawResource(R.raw.finn1);
        int size = 0;

        try
        {
            size = fis.available();
            buffer = new byte[size];
            fis.read(buffer);
            fis.close();

            boolean exists = (new File(musicDirPath + filename)).exists();
            if (exists)
            {
                Toast.makeText(this, "File exists!", Toast.LENGTH_SHORT).show();
            }
            else
            {
                FileOutputStream save = new FileOutputStream(musicDirPath + filename);
                save.write(buffer);
                save.flush();
                save.close();
                Toast.makeText(this, "File saved!", Toast.LENGTH_SHORT).show();
            }
        }
        catch (IOException e)
        {
            Toast.makeText(this, e.getMessage(), Toast.LENGTH_LONG).show();
            e.printStackTrace();
        }
    }

    /* Checks if external storage is available for read and write */
    public boolean isExternalStorageWritable() {
        String state = Environment.getExternalStorageState();
        if (Environment.MEDIA_MOUNTED.equals(state)) {
            return true;
        }
        return false;
    }

    /* Checks if external storage is available to at least read */
    public boolean isExternalStorageReadable() {
        String state = Environment.getExternalStorageState();
        if (Environment.MEDIA_MOUNTED.equals(state) ||
                Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) {
            return true;
        }
        return false;
    }
}

activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.test.mediaplayerproblem.MainActivity">

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical">
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/textView1"
            android:text="Hello World!"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toTopOf="parent"/>

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

            <Button
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/saveFile"
                android:text="Save"
                android:onClick="saveFile"/>
            <Button
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/playButton"
                android:text="Play"
                android:onClick="playFile"/>
            <Button
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/stopButton"
                android:text="Stop"
                android:onClick="stopFile"/>
        </LinearLayout>
    </LinearLayout>

</android.support.constraint.ConstraintLayout>

Answer 3

好的。因为 getExternalFilesDir 似乎不起作用，所以我使用了以下解决方法：

public String getExternalPath(){
    String removableStoragePath = "";
    File fileList[] = new File("/storage/").listFiles();
    for (File file : fileList)
    { if(!file.getAbsolutePath().equalsIgnoreCase(Environment.getExternalStorageDirectory().getAbsolutePath()) && file.isDirectory() && file.canRead())
        removableStoragePath = file.getAbsolutePath(); }
    return removableStoragePath;
}

这段代码在我测试过的每个模拟器上都运行良好。如果有人遇到同样的问题，希望这会有所帮助。

FileNotFoundException 使用媒体播放器

FileNotFoundException using mediaplayer

java

android

exception

file

android-mediaplayer