Question

我正在尝试将输出音频文件保存在一个单独的新文件夹中，但是当我尝试启动应用程序时它会崩溃：

我的文件创建代码如下：

在 onCreate（） aof mainActivity：

protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
         play=(Button)findViewById(R.id.button3);
          stop=(Button)findViewById(R.id.button2);
          record=(Button)findViewById(R.id.button);


         stop.setEnabled(false);
          play.setEnabled(false);

          final File path =
                Environment.getExternalStoragePublicDirectory
                (
                    //Environment.DIRECTORY_PICTURES
                    //Environment.DIRECTORY_DCIM
                    Environment.DIRECTORY_DCIM + "/Utkarshrecord/"
                );

            // Make sure the sound directory exists.
            if(!path.exists())
            {
                path.mkdirs();
            }

           try {
               file.createTempFile("sound", ".3gp", path);

            myAudioRecorder=new MediaRecorder();
            myAudioRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
            myAudioRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
            myAudioRecorder.setOutputFile(file.getAbsolutePath());

        } catch (IOException e2) {
            // TODO Auto-generated catch block
            e2.printStackTrace();
        }

记录停止和播放有三个按钮：

记录的代码：

record.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { try { myAudioRecorder.prepare(); myAudioRecorder.start(); } catch (IllegalStateException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } record.setEnabled(false); stop.setEnabled(true); Toast.makeText(getApplicationContext(), "Recording started", Toast.LENGTH_LONG).show(); } });

代码停止：

stop.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) throws IllegalArgumentException,SecurityException,IllegalStateException { try{ myAudioRecorder.stop(); myAudioRecorder.release(); myAudioRecorder = null; }catch(Exception e){ e.printStackTrace(); } Toast.makeText(getApplicationContext(), "Audio recorded successfully",Toast.LENGTH_LONG).show(); stop.setEnabled(false); play.setEnabled(true); } });

错误如下：

10-05 14:44:04.910: E/AndroidRuntime(31147): FATAL EXCEPTION: main 10-05 14:44:04.910: E/AndroidRuntime(31147): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.sensorlist/com.example.sensorlist.MainActivity}: java.lang.NullPointerException 10-05 14:44:04.910: E/AndroidRuntime(31147): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2343) 10-05 14:44:04.910: E/AndroidRuntime(31147): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2395) 10-05 14:44:04.910: E/AndroidRuntime(31147): at android.app.ActivityThread.access$600(ActivityThread.java:162) 10-05 14:44:04.910: E/AndroidRuntime(31147): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1364) 10-05 14:44:04.910: E/AndroidRuntime(31147): at android.os.Handler.dispatchMessage(Handler.java:107) 10-05 14:44:04.910: E/AndroidRuntime(31147): at android.os.Looper.loop(Looper.java:194) 10-05 14:44:04.910: E/AndroidRuntime(31147): at android.app.ActivityThread.main(ActivityThread.java:5371) 10-05 14:44:04.910: E/AndroidRuntime(31147): at java.lang.reflect.Method.invokeNative(Native Method) 10-05 14:44:04.910: E/AndroidRuntime(31147): at java.lang.reflect.Method.invoke(Method.java:525) 10-05 14:44:04.910: E/AndroidRuntime(31147): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:833) 10-05 14:44:04.910: E/AndroidRuntime(31147): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600) 10-05 14:44:04.910: E/AndroidRuntime(31147): at dalvik.system.NativeStart.main(Native Method) 10-05 14:44:04.910: E/AndroidRuntime(31147): Caused by: java.lang.NullPointerException 10-05 14:44:04.910: E/AndroidRuntime(31147): at java.io.File.fixSlashes(File.java:185) 10-05 14:44:04.910: E/AndroidRuntime(31147): at java.io.File.<init>(File.java:134) 10-05 14:44:04.910: E/AndroidRuntime(31147): at java.io.FileOutputStream.<init>(FileOutputStream.java:128) 10-05 14:44:04.910: E/AndroidRuntime(31147): at java.io.FileOutputStream.<init>(FileOutputStream.java:117) 10-05 14:44:04.910: E/AndroidRuntime(31147): at com.example.sensorlist.MainActivity.onCreate(MainActivity.java:64) 10-05 14:44:04.910: E/AndroidRuntime(31147): at android.app.Activity.performCreate(Activity.java:5122) 10-05 14:44:04.910: E/AndroidRuntime(31147): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1081) 10-05 14:44:04.910: E/AndroidRuntime(31147): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2307) 10-05 14:44:04.910: E/AndroidRuntime(31147): ... 11 more

我应该怎么做才能删除它？

Answer 1

因为你所犯的一些错误非常愚蠢！

错误1：

file.createTempFile("sound", ".3gp", path);

对于static参考，它应该是

File.createTempFile("sound", ".3gp", path);

它应该存储在文件中，直到现在为null！

第二个错误：

播放按钮中的

：将其更改为

 m.setDataSource(file.getAbsolutePath());

文件创建错误中的java.lang.NullPointerException

1 个答案: