android - 为什么我在测试 MediaRecorder 示例时出现致命异常？

Question

我在真实设备上使用 Android Studio 测试示例 E:\Android_SDK\samples\android-22\media\MediaRecorder，出现以下错误，为什么？示例中是否存在一些错误？

顺便说一句，我的安卓版本是5.1

09-28 16:09:31.683  17233-17233/com.example.android.mediarecorder E/Zygote﹕ v2
09-28 16:09:31.683  17233-17233/com.example.android.mediarecorder E/SELinux﹕ [DEBUG] get_category: variable seinfo: default sensitivity: NULL, cateogry: NULL
09-28 16:10:06.343  17233-17772/com.example.android.mediarecorder E/MediaRecorder﹕ start failed: -19
09-28 16:10:06.343  17233-17772/com.example.android.mediarecorder E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #1
    Process: com.example.android.mediarecorder, PID: 17233
    java.lang.RuntimeException: An error occured while executing doInBackground()
            at android.os.AsyncTask$3.done(AsyncTask.java:304)
            at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
            at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
            at java.util.concurrent.FutureTask.run(FutureTask.java:242)
            at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
            at java.lang.Thread.run(Thread.java:818)
     Caused by: java.lang.RuntimeException: start failed.
            at android.media.MediaRecorder.start(Native Method)
            at com.example.android.mediarecorder.MainActivity$MediaPrepareTask.doInBackground(MainActivity.java:208)
            at com.example.android.mediarecorder.MainActivity$MediaPrepareTask.doInBackground(MainActivity.java:200)
            at android.os.AsyncTask$2.call(AsyncTask.java:292)
            at java.util.concurrent.FutureTask.run(FutureTask.java:237)
            at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
            at java.lang.Thread.run(Thread.java:818)

已添加

还有，我把AndroidManifest.xml中的android:screenOrientation="landscape"去掉后效果很好，但不知道为什么？

Answer 1

MediaRecorder样本作品在 Landscape模式，并使其在 portrait 中工作模式以及您需要按确切顺序添加以下代码!

这是代码:-

为 portrait 添加这个支持mCamera

mCamera.setDisplayOrientation(90);

并支持Audio/Video编码器和 OutputFormat添加这个

            mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
            mMediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.MPEG_4_SP);
            mMediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);

下面是您的完整方法 prepareVideoRecorder

private boolean prepareVideoRecorder(){

        // BEGIN_INCLUDE (configure_preview)
        mCamera = CameraHelper.getDefaultCameraInstance();
        mCamera.setDisplayOrientation(90);
        // We need to make sure that our preview and recording video size are supported by the
        // camera. Query camera to find all the sizes and choose the optimal size given the


        try {
                // Requires API level 11+, For backward compatibility use {@link setPreviewDisplay}
                // with {@link SurfaceView}
                mCamera.setPreviewTexture(mPreview.getSurfaceTexture());

        } catch (IOException e) {
            Log.e(TAG, "Surface texture is unavailable or unsuitable" + e.getMessage());
            return false;
        }
        // END_INCLUDE (configure_preview)


        // BEGIN_INCLUDE (configure_media_recorder)
        mMediaRecorder = new MediaRecorder();

        // Step 1: Unlock and set camera to MediaRecorder
        mCamera.unlock();
        mMediaRecorder.setCamera(mCamera);

        // Step 2: Set sources
        mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
        mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.DEFAULT);

        mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
        mMediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.MPEG_4_SP);
        mMediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);

        mMediaRecorder.setOrientationHint(90);

        // Step 3: Set a CamcorderProfile (requires API Level 8 or higher)

        mMediaRecorder.setOutputFile(CameraHelper.getOutputMediaFile(
                CameraHelper.MEDIA_TYPE_VIDEO).toString());
        //
        //mMediaRecorder.setPreviewDisplay(SufaceView);
        // Step 4: Set output file

        // END_INCLUDE (configure_media_recorder)

        // Step 5: Prepare configured MediaRecorder
        try {
            mMediaRecorder.prepare();
            } catch (IllegalStateException e) {
            Log.d(TAG, "IllegalStateException preparing MediaRecorder: " + e.getMessage());
            releaseMediaRecorder();
            return false;
        } catch (IOException e) {
            Log.d(TAG, "IOException preparing MediaRecorder: " + e.getMessage());
            releaseMediaRecorder();
            return false;
        }
        return true;
    }

最后你可以删除 screenOrientation来自 list

android:screenOrientation="landscape"

上面的代码在 orientation 中都有效。但是Camera显示始终为 90 degree所以你需要通过正确处理你的方向来做出改变。