我有一个在Android 2.2上运行的三星Galaxy选项卡。我开发了一个简单的程序来分别录制音频和视频。它在我的galaxy选项卡上正常工作。但是，在将其升级到android 2.3.3后，一切都发生了变化。我的代码从那一刻开始停止工作。这是我的代码，显示了这个意外的（对我:) :)行为：
// import statements
public class CameraPreview extends Activity implements SurfaceHolder.Callback {
Camera camera;
SurfaceView surfaceView;
SurfaceHolder surfaceHolder;
boolean previewing = false;
LayoutInflater controlInflater = null;
Button recordButton;
/** Called when the activity is first created. */
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.camera);
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
getWindow().setFormat(PixelFormat.UNKNOWN);
surfaceView = (SurfaceView) findViewById(R.id.camerapreview);
surfaceHolder = surfaceView.getHolder();
surfaceHolder.addCallback(this);
surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
controlInflater = LayoutInflater.from(getBaseContext());
View viewControl = controlInflater.inflate(R.layout.control, null);
LayoutParams layoutParamsControl = new LayoutParams(
LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);
this.addContentView(viewControl, layoutParamsControl);
recordButton = (Button)viewControl.findViewById(R.id.start_recording);
recordButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
startRecording();
}
});
}
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
if (previewing) {
camera.stopPreview();
previewing = false;
}
if (camera != null) {
try {
camera.setPreviewDisplay(surfaceHolder);
camera.startPreview();
previewing = true;
} catch (IOException e) {
e.printStackTrace();
}
}
}
public void surfaceCreated(SurfaceHolder holder) {
camera = Camera.open();
}
public void surfaceDestroyed(SurfaceHolder holder) {
camera.stopPreview();
camera.release();
camera = null;
previewing = false;
}
private void startRecording() {
try {
stopPreview();
Thread video = new Thread(new Runnable() {
public void run() {
videoRecorder = new MediaRecorder();
videoRecorder.setPreviewDisplay(surfaceView.getHolder().getSurface());
videoRecorder.setVideoSource(MediaRecorder.VideoSource.DEFAULT);
videoRecorder.setOutputFormat(2);
videoRecorder.setVideoEncodingBitRate(56 * 8 * 1024);
videoRecorder.setVideoSize(176, 144);
videoRecorder.setVideoFrameRate(12);
videoRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.MPEG_4_SP);
videoRecorder.setOutputFile("/sdcard/video.m4e");
try {
videoRecorder.prepare();
} catch (IllegalStateException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
videoRecorder.start();
}
});
video.start();
Thread audio = new Thread(new Runnable() {
public void run() {
audioRecorder = new MediaRecorder();
audioRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
audioRecorder.setOutputFormat(MediaRecorder.OutputFormat.RAW_AMR);
audioRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
audioRecorder.setOutputFile("/sdcard/audio.amr");
try {
audioRecorder.prepare();
} catch (IllegalStateException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
audioRecorder.start();
}
});
audio.start();
} catch (Exception e) {
Log.e("streamer", "Unable to start recording", e);
}
}
private void stopPreview() {
if (camera == null) {
throw new RuntimeException();
}
camera.stopPreview();
camera.release();
camera = null;
}
}
以下是日志输出：
PID TAG MESSAGE
D 75 CameraHardwareSec MemoryHeapBase(fd(27), size(5760128), width(800), height(600))
E 75 AuthorDriver Command 13 completed with error -17
E 7169 MediaRecorder prepare failed: -17
W 7169 System.err java.io.IOException: prepare failed.
W 7169 System.err at android.media.MediaRecorder._prepare(Native Method)
W 7169 System.err at android.media.MediaRecorder.prepare(MediaRecorder.java:592)
W 7169 System.err at com.video.streamer.view.CameraPreview$2.run(CameraPreview.java:121)
W 7169 System.err at java.lang.Thread.run(Thread.java:1019)
E 7169 MediaRecorder start called in an invalid state: 0
W 7169 dalvikvm threadid=10: thread exiting with uncaught exception (group=0x40015578)
E 7169 AndroidRuntime FATAL EXCEPTION: Thread-11
E 7169 AndroidRuntime java.lang.IllegalStateException
E 7169 AndroidRuntime at android.media.MediaRecorder.start(Native Method)
E 7169 AndroidRuntime at com.video.streamer.view.CameraPreview$2.run(CameraPreview.java:127)
E 7169 AndroidRuntime at java.lang.Thread.run(Thread.java:1019)
W 118 ActivityManager Force finishing activity com.video.streamer.view/.CameraPreview
以下是用于布局目的的XML文件。 camera.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<SurfaceView
android:id="@+id/camerapreview"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
</LinearLayout>
control.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="bottom"
>
<Button
android:id="@+id/start_recording"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text=" * Start Recording"
android:layout_gravity="right"
android:layout_margin="10px"
/>
</LinearLayout>
我在AndroidManifest.xml
<uses-permission android:name="android.permission.CAMERA"></uses-permission>
<uses-permission android:name="android.permission.RECORD_AUDIO"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
我从roman10家伙博客获得的视频录制示例：Android Video Recording API–Illustrated with an Example也正常使用我的Android 2.2。但是，由于我的升级，这也停止了工作。
使用android 2.3.3录制视频时是否有任何遗漏。我该如何解决这个问题？
答案 0 :(得分：3)
Android SDK不断更改其API，因此当你对路径进行硬编码时会出错：
videoRecorder.setOutputFile("/sdcard/video.m4e");//or
audioRecorder.setOutputFile("/sdcard/audio.amr");
如果API更改目录，您的应用程序将被破坏。获取文件路径的更好方法是使用API函数：
mVideoFileName = Environment.getExternalStorageDirectory().getAbsolutePath();
mVideoFileName += "/video.m4e";
mAudioFileName = Environment.getExternalStorageDirectory().getAbsolutePath();
mAudioFileName += "/audio.amr";