Java Android MediaRecorder准备失败EROFS

我只想使用麦克风录制声音并将其存储到内部存储器中。这是我的代码：

EditText sentence = (EditText) findViewById(R.id.sentence);
MediaRecorder  mRecorder = new MediaRecorder();
mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
mRecorder.setAudioEncoder(MediaRecorder.OutputFormat.AMR_NB);

try {
        String filename = sentence.getText().toString();
        mRecorder.setOutputFile(getFilesDir().getAbsolutePath() + File.separator + filename + ".3gp");
        mRecorder.prepare();
        mRecorder.start();
        } catch (IllegalStateException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
        } catch (IOException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
        }
        Toast.makeText(getApplicationContext(), "Recording started", Toast.LENGTH_LONG).show();

再过一会儿：

mRecorder.stop();
            mRecorder.release();
            //mRecorder  = null;
            Toast.makeText(getApplicationContext(), "Audio recorded successfully", Toast.LENGTH_LONG).show();
        }

问题是，由于以下错误，它无法保存任何文件：

java.io.FileNotFoundException: /Test: open failed: EROFS (Read-only file system)
at libcore.io.IoBridge.open(IoBridge.java:409)
at java.io.FileOutputStream.<init>(FileOutputStream.java:88)
at java.io.FileOutputStream.<init>(FileOutputStream.java:128)
at java.io.FileOutputStream.<init>(FileOutputStream.java:117)
at android.media.MediaRecorder.prepare(MediaRecorder.java:811)
at com.example.germansentences.AddnewSentence.sendRecording(AddnewSentence.java:160)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at android.view.View$1.onClick(View.java:3960)
at android.view.View.performClick(View.java:4626)
at android.view.View$PerformClick.run(View.java:19293)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:157)
at android.app.ActivityThread.main(ActivityThread.java:5293)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1265)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)
at dalvik.system.NativeStart.main(Native Method)
Caused by: libcore.io.ErrnoException: open failed: EROFS (Read-only file system)
    at libcore.io.Posix.open(Native Method)
    at libcore.io.BlockGuardOs.open(BlockGuardOs.java:110)
    at libcore.io.IoBridge.open(IoBridge.java:393)
    ... 19 more

请帮帮我，这个错误让我发疯了。为什么不允许我向应用程序内部/外部存储器写入数据

    <?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.germansentences"
    android:versionCode="1"
    android:versionName="1.0"
    android:installLocation="auto" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="19" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>
    <uses-permission android:name="android.permission.WRITE_INTERNAL_STORAGE"></uses-permission>
    <uses-permission android:name="android.permission.RECORD_AUDIO" /> 
    <uses-permission android:name="android.permission.STORAGE" />
    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
    ...
     </application>

    </manifest>