我正在開發定製的相機應用程序。當應用程序啓動相機打開時,底部有三個按鈕。嘗試拍攝新照片時應用程序崩潰
- 捕獲(拍照)。
- 採取新的(從預覽返回到相機再次拍照。)
- 不使用任何東西。
一切工作正常。按下捕捉拍攝照片並精確預覽拍攝的照片。但是當我按下新按鈕進入相機模式從預覽模式應用程序崩潰不知道我在做什麼錯了。以下是我正在使用的代碼。
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;
}
}
在此先感謝。 最後 這裏是我的錯誤的logcat:
02-21 18:24:01.868:E/AndroidRuntime(937):致命異常: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)
後logcat在這裏。 – 2013-02-21 17:12:38
無法看到任何logcat有什麼建議嗎? – 2013-02-21 17:16:36
您需要先讓LogCat工作。你在哪裏運行這個應用程序?如果它在沒有後置攝像頭或模擬器的設備上,則可能會從Camera.open()返回空值。因此,NullPointerException。 – 2013-02-21 17:21:03