我正在开发定制的相机应用程序。当应用程序启动相机打开时,底部有三个按钮。尝试拍摄新照片时应用程序崩溃
- 捕获(拍照)。
- 采取新的(从预览返回到相机再次拍照。)
- 不使用任何东西。
一切工作正常。按下捕捉拍摄照片并精确预览拍摄的照片。但是当我按下新按钮进入相机模式从预览模式应用程序崩溃不知道我在做什么错了。以下是我正在使用的代码。
public class MainActivity extends Activity {
protected static final String TAG = null;
private Camera mCamera;
private CameraPreview mPreview;
public static final int MEDIA_TYPE_IMAGE = 1;
static int result;
static int degrees = 90;
private Button captureButton, btn_new;
public FrameLayout preview;
private static File mediaFile;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Create an instance of Camera
mCamera = getCameraInstance();
// Create our Preview view and set it as the content of our activity.
mPreview = new CameraPreview(this, mCamera);
FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
preview.addView(mPreview);
captureButton = (Button) findViewById(R.id.button_capture);
captureButton.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
// get an image from the camera
mCamera.takePicture(null, null, mPicture);
}
}
);
btn_new = (Button) findViewById(R.id.button_new);
btn_new.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
mCamera = getCameraInstance();
//preview = (FrameLayout) findViewById(R.id.camera_preview);
//preview.addView(mPreview);
}
});
}
private PictureCallback mPicture = new PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
File pictureFile = getOutputMediaFile(MEDIA_TYPE_IMAGE);
if (pictureFile == null){
return;
}
try {
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.close();
} catch (FileNotFoundException e) {
Log.d(TAG, "File not found: " + e.getMessage());
} catch (IOException e) {
Log.d(TAG, "Error accessing file: " + e.getMessage());
}
}
};
/** Create a File for saving an image or video */
private static File getOutputMediaFile(int type){
// To be safe, you should check that the SDCard is mounted
// using Environment.getExternalStorageState() before doing this.
File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM), "Camera");
// Create the storage directory if it does not exist
if (! mediaStorageDir.exists()){
if (! mediaStorageDir.mkdirs()){
Log.d("MyCameraApp", "failed to create directory");
return null;
}
}
// Create a media file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
if (type == MEDIA_TYPE_IMAGE){
mediaFile = new File(mediaStorageDir.getPath() + File.separator +
"IMG_"+ timeStamp + ".jpg");
}
else {
return null;
}
return mediaFile;
}
@SuppressWarnings("null")
public static Camera getCameraInstance(){
Camera c = null;
Context context = null;
try{
c = Camera.open();
//setCameraDisplayOrientation(MainActivity, 0, c);
c.setDisplayOrientation(degrees);
}
catch (Exception e) {
Toast.makeText(context.getApplicationContext(),"Camera is not available" , Toast.LENGTH_LONG).show();
}
return c;
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
在此先感谢。 最后 这里是我的错误的logcat:
02-21 18:24:01.868:E/AndroidRuntime(937):致命异常:主要 02-21 18:24:01.868:E/AndroidRuntime( 937):java.lang.NullPointerException 02-21 18:24:01.868:E/AndroidRuntime(937):at com.example.facebooktag.MainActivity.getCameraInstance(MainActivity.java:136) 02-21 18:24: 01.868:E/AndroidRuntime(937):at com.example.facebooktag.MainActivity $ 3.onClick(MainActivity.java:66) 02-21 18:24:01.868:E/AndroidRuntime(937):at android.view.View .performClick(View.java:4202) 02-21 18:24:01.868:E/AndroidRuntime(937):at android.view .View $ PerformClick.run(View.java:17340) 02-21 18:24:01.868:E/AndroidRuntime(937):at android.os.Handler.handleCallback(Handler.java:725) 02-21 18 :24:01.868:E/AndroidRuntime(937):at android.os.Handler.dispatchMessage(Handler.java:92) 02-21 18:24:01.868:E/AndroidRuntime(937):at android.os.Looper .loop(Looper.java:137) 02-21 18:24:01.868:E/AndroidRuntime(937):at android.app.ActivityThread.main(ActivityThread.java:5039) 02-21 18:24:01.868 :E/AndroidRuntime(937):at java.lang.reflect.Method.invokeNative(Native Method) 02-21 18:24:01.868:E/AndroidRuntime(937):at java.lang.reflect.Method.invoke Method.java:511) 02-21 18:24:01.868:E/AndroidRuntime(937):at com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:793) 02-21 18:24:01.868:E/AndroidRuntime(937):at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 02-21 18:24:01.868:E/AndroidRuntime 937):at dalvik.system.NativeStart.main(Native Method)
后logcat在这里。 – 2013-02-21 17:12:38
无法看到任何logcat有什么建议吗? – 2013-02-21 17:16:36
您需要先让LogCat工作。你在哪里运行这个应用程序?如果它在没有后置摄像头或模拟器的设备上,则可能会从Camera.open()返回空值。因此,NullPointerException。 – 2013-02-21 17:21:03