如何在android上播放用MediaRecorder录制的3gp文件

Question

我看了this主题并按照它的建议行事，但我仍然无法播放我的3gp文件。这是我的代码：

  /**
     * Starts a new recording.
     */
    public void start() throws IOException {
        String state = android.os.Environment.getExternalStorageState();
        if(!state.equals(android.os.Environment.MEDIA_MOUNTED))  {
            throw new IOException("SD Card is not mounted.  It is " + state + ".");
        }

        // make sure the directory we plan to store the recording in exists
        File directory = new File(path).getParentFile();
        if (!directory.exists() && !directory.mkdirs()) {
            throw new IOException("Path to file could not be created.");
        }

        recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
        recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
        recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
        recorder.setOutputFile(path);
        recorder.setOnErrorListener(new MediaRecorder.OnErrorListener() {
            @Override
            public void onError(MediaRecorder mediaRecorder, int i, int i1) {
                Log.d("phone record error",i+","+i1);
            }
        });
        recorder.setOnInfoListener(new MediaRecorder.OnInfoListener() {
            @Override
            public void onInfo(MediaRecorder mediaRecorder, int i, int i1) {
                Log.d("phone record info",i+","+i1);
            }
        });
        recorder.prepare();
        recorder.start();
    }

    /**
     * Stops a recording that has been previously started.
     */
    public void stop() throws IOException {
        recorder.stop();
        recorder.reset();
        recorder.release();
    }

录制期间控制台中没有例外。

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