我正在尝试录制视频并保存到外部SD卡。但是，每次我收到三个错误
任何人都知道任何教程或者可以帮助纠正我的代码。
任何人都可以帮助我，因为我得到了这三个错误
12-09 14:12:23.592: E/AndroidRuntime(4377): java.lang.NullPointerException
12-09 14:12:23.592: E/AndroidRuntime(4377): at com.mahesh.VideoStreamActivity.surfaceChanged(VideoStreamActivity.java:71)
12-09 14:12:23.592: E/AndroidRuntime(4377): at android.view.SurfaceView.updateWindow(SurfaceView.java:568)
12-09 14:12:23.592: E/AndroidRuntime(4377): at android.view.SurfaceView.access$000(SurfaceView.java:82)
12-09 14:12:23.592: E/AndroidRuntime(4377): at android.view.SurfaceView$3.onPreDraw(SurfaceView.java:171)
12-09 14:12:23.592: E/AndroidRuntime(4377): at android.view.ViewTreeObserver.dispatchOnPreDraw(ViewTreeObserver.java:590)
12-09 14:12:23.592: E/AndroidRuntime(4377): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1590)
12-09 14:12:23.592: E/AndroidRuntime(4377): at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2382)
12-09 14:12:23.592: E/AndroidRuntime(4377): at android.os.Handler.dispatchMessage(Handler.java:99)
12-09 14:12:23.592: E/AndroidRuntime(4377): at android.os.Looper.loop(Looper.java:137)
12-09 14:12:23.592: E/AndroidRuntime(4377): at android.app.ActivityThread.main(ActivityThread.java:4340)
12-09 14:12:23.592: E/AndroidRuntime(4377): at java.lang.reflect.Method.invokeNative(Native Method)
12-09 14:12:23.592: E/AndroidRuntime(4377): at java.lang.reflect.Method.invoke(Method.java:511)
12-09 14:12:23.592: E/AndroidRuntime(4377): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
12-09 14:12:23.592: E/AndroidRuntime(4377): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
12-09 14:12:23.592: E/AndroidRuntime(4377): at dalvik.system.NativeStart.main(Native Method)
12-09 14:17:02.723: E/CAMERA_TUTORIAL(4596): /data/data/com.mahesh/cache/sdcard/videooutput: open failed: ENOENT (No such file or directory)
12-09 14:17:02.723: W/System.err(4596): java.io.FileNotFoundException: /data/data/com.mahesh/cache/sdcard/videooutput: open failed: ENOENT (No such file or directory)
12-09 14:17:02.734: W/System.err(4596): at libcore.io.IoBridge.open(IoBridge.java:406)
12-09 14:17:02.734: W/System.err(4596): at java.io.FileOutputStream.<init>(FileOutputStream.java:88)
12-09 14:17:02.734: W/System.err(4596): at java.io.FileOutputStream.<init>(FileOutputStream.java:128)
12-09 14:17:02.734: W/System.err(4596): at java.io.FileOutputStream.<init>(FileOutputStream.java:117)
12-09 14:17:02.734: W/System.err(4596): at android.media.MediaRecorder.prepare(MediaRecorder.java:623)
12-09 14:17:02.734: W/System.err(4596): at com.mahesh.VideoStreamActivity.startRecording(VideoStreamActivity.java:119)
12-09 14:17:02.734: W/System.err(4596): at com.mahesh.VideoStreamActivity.surfaceCreated(VideoStreamActivity.java:50)
12-09 14:17:02.743: W/System.err(4596): at android.view.SurfaceView.updateWindow(SurfaceView.java:562)
12-09 14:17:02.743: W/System.err(4596): at android.view.SurfaceView.access$000(SurfaceView.java:82)
12-09 14:17:02.743: W/System.err(4596): at android.view.SurfaceView$3.onPreDraw(SurfaceView.java:171)
12-09 14:17:02.743: W/System.err(4596): at android.view.ViewTreeObserver.dispatchOnPreDraw(ViewTreeObserver.java:590)
12-09 14:17:02.743: W/System.err(4596): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1590)
12-09 14:17:02.743: W/System.err(4596): at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2382)
12-09 14:17:02.743: W/System.err(4596): at android.os.Handler.dispatchMessage(Handler.java:99)
12-09 14:17:02.743: W/System.err(4596): at android.os.Looper.loop(Looper.java:137)
12-09 14:17:02.743: W/System.err(4596): at android.app.ActivityThread.main(ActivityThread.java:4340)
12-09 14:17:02.753: W/System.err(4596): at java.lang.reflect.Method.invokeNative(Native Method)
12-09 14:17:02.753: W/System.err(4596): at java.lang.reflect.Method.invoke(Method.java:511)
12-09 14:17:02.753: W/System.err(4596): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
12-09 14:17:02.753: W/System.err(4596): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
12-09 14:17:02.753: W/System.err(4596): at dalvik.system.NativeStart.main(Native Method)
12-09 14:17:02.753: W/System.err(4596): Caused by: libcore.io.ErrnoException: open failed: ENOENT (No such file or directory)
12-09 14:17:02.753: W/System.err(4596): at libcore.io.Posix.open(Native Method)
12-09 14:17:02.753: W/System.err(4596): at libcore.io.BlockGuardOs.open(BlockGuardOs.java:98)
12-09 14:17:02.763: W/System.err(4596): at libcore.io.IoBridge.open(IoBridge.java:390)
12-09 14:17:02.763: W/System.err(4596): ... 20 more
12-09 14:17:02.773: D/AndroidRuntime(4596): Shutting down VM
12-09 14:17:02.773: W/dalvikvm(4596): threadid=1: thread exiting with uncaught exception (group=0x409951f8)
12-09 14:17:02.793: E/AndroidRuntime(4596): FATAL EXCEPTION: main
12-09 14:17:02.793: E/AndroidRuntime(4596): java.lang.RuntimeException: setParameters failed
12-09 14:17:02.793: E/AndroidRuntime(4596): at android.hardware.Camera.native_setParameters(Native Method)
12-09 14:17:02.793: E/AndroidRuntime(4596): at android.hardware.Camera.setParameters(Camera.java:1253)
12-09 14:17:02.793: E/AndroidRuntime(4596): at com.mahesh.VideoStreamActivity.surfaceChanged(VideoStreamActivity.java:68)
12-09 14:17:02.793: E/AndroidRuntime(4596): at android.view.SurfaceView.updateWindow(SurfaceView.java:568)
12-09 14:17:02.793: E/AndroidRuntime(4596): at android.view.SurfaceView.access$000(SurfaceView.java:82)
12-09 14:17:02.793: E/AndroidRuntime(4596): at android.view.SurfaceView$3.onPreDraw(SurfaceView.java:171)
12-09 14:17:02.793: E/AndroidRuntime(4596): at android.view.ViewTreeObserver.dispatchOnPreDraw(ViewTreeObserver.java:590)
12-09 14:17:02.793: E/AndroidRuntime(4596): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1590)
12-09 14:17:02.793: E/AndroidRuntime(4596): at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2382)
12-09 14:17:02.793: E/AndroidRuntime(4596): at android.os.Handler.dispatchMessage(Handler.java:99)
12-09 14:17:02.793: E/AndroidRuntime(4596): at android.os.Looper.loop(Looper.java:137)
12-09 14:17:02.793: E/AndroidRuntime(4596): at android.app.ActivityThread.main(ActivityThread.java:4340)
12-09 14:17:02.793: E/AndroidRuntime(4596): at java.lang.reflect.Method.invokeNative(Native Method)
12-09 14:17:02.793: E/AndroidRuntime(4596): at java.lang.reflect.Method.invoke(Method.java:511)
12-09 14:17:02.793: E/AndroidRuntime(4596): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
12-09 14:17:02.793: E/AndroidRuntime(4596): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
12-09 14:17:02.793: E/AndroidRuntime(4596): at dalvik.system.NativeStart.main(Native Method)
code>>>>>>>>>>>>>>>>>>>>>>>>>
import java.io.File;
import java.io.IOException;
import android.app.Activity;
import android.graphics.PixelFormat;
import android.hardware.Camera;
import android.media.MediaRecorder;
import android.os.Bundle;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.widget.Toast;
public class VideoStreamActivity extends Activity implements SurfaceHolder.Callback{
private static final String TAG = "CAMERA_TUTORIAL";
private SurfaceView surfaceView;
private SurfaceHolder surfaceHolder;
private Camera camera;
private boolean previewRunning;
private MediaRecorder mediaRecorder;
private final int maxDurationInMs = 20000;
private final long maxFileSizeInBytes = 500000;
private final int videoFramesPerSecond = 20;
private File tempFile;
String cacheFileName="/sdcard/videooutput";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.camera_surface);
surfaceView = (SurfaceView) findViewById(R.id.surface_camera);
surfaceHolder = surfaceView.getHolder();
surfaceHolder.addCallback(this);
surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
camera = Camera.open();
if (camera != null){
Camera.Parameters params = camera.getParameters();
camera.setParameters(params);
}
else {
Toast.makeText(getApplicationContext(), "Camera not available!", Toast.LENGTH_LONG).show();
finish();
}
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
if (previewRunning){
camera.stopPreview();
}
Camera.Parameters p = camera.getParameters();
p.getPreferredPreviewSizeForVideo();
p.setPreviewSize(width, height);
p.setPreviewFormat(PixelFormat.JPEG);
camera.setParameters(p);
try {
camera.setPreviewDisplay(holder);
camera.startPreview();
previewRunning = true;
}
catch (IOException e) {
Log.e(TAG,e.getMessage());
e.printStackTrace();
}
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
camera.stopPreview();
previewRunning = false;
camera.release();
}
public boolean startRecording(){
try {
camera.unlock();
mediaRecorder = new MediaRecorder();
mediaRecorder.setCamera(camera);
mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.DEFAULT);
mediaRecorder.setMaxDuration(maxDurationInMs);
tempFile = new File(getCacheDir(),cacheFileName);
mediaRecorder.setOutputFile(tempFile.getPath());
mediaRecorder.setVideoFrameRate(videoFramesPerSecond);
mediaRecorder.setVideoSize(surfaceView.getWidth(), surfaceView.getHeight());
mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.DEFAULT);
mediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.DEFAULT);
mediaRecorder.setPreviewDisplay(surfaceHolder.getSurface());
mediaRecorder.setMaxFileSize(maxFileSizeInBytes);
mediaRecorder.prepare();
mediaRecorder.start();
return true;
} catch (IllegalStateException e) {
Log.e(TAG,e.getMessage());
e.printStackTrace();
return false;
} catch (IOException e) {
Log.e(TAG,e.getMessage());
e.printStackTrace();
return false;
}
}
public void stopRecording(){
mediaRecorder.stop();
camera.lock();
}
}
答案 0 :(得分：3)
查看您正在打开的文件路径：
/data/data/com.mahesh/cache/sdcard/videooutput
看起来你正在使用错误的路径打开文件。没有代码，很难说出其他任何内容。
答案 1 :(得分：0)
这对开发工具来说要容易得多。第一个表示您正在调用指向尚未实例化的对象的指针，或者指针未设置地址。
第二个是相当明显的，因为你试图打开一个不存在的文件，可能是由于路径或文件名不正确。
第三个很可能会在其他两个被修复之后再去。
尝试在错误消息中指定的行上放置断点并检查传递的值。