我正在编写一个程序，我正在拍摄照片，然后想要将照片存储到SD卡中，最后尝试调整现有图像的大小（然后用旧图像重写）。
我的代码几乎可以在所有设备上正常工作，但仅在三星设备上遇到此问题。
当我拍摄图像时，我无法将图像存储到SD卡中
logcat的：
12-05 18:23:15.407: E/AndroidRuntime(2378): FATAL EXCEPTION: main
12-05 18:23:15.407: E/AndroidRuntime(2378): java.lang.NullPointerException
12-05 18:23:15.407: E/AndroidRuntime(2378): at android.graphics.Bitmap.createScaledBitmap(Bitmap.java:461)
12-05 18:23:15.407: E/AndroidRuntime(2378): at com.example.kdh.TakePhotoActivity$1.onPictureTaken(TakePhotoActivity.java:325)
12-05 18:23:15.407: E/AndroidRuntime(2378): at android.hardware.Camera$EventHandler.handleMessage(Camera.java:789)
12-05 18:23:15.407: E/AndroidRuntime(2378): at android.os.Handler.dispatchMessage(Handler.java:99)
12-05 18:23:15.407: E/AndroidRuntime(2378): at android.os.Looper.loop(Looper.java:137)
12-05 18:23:15.407: E/AndroidRuntime(2378): at android.app.ActivityThread.main(ActivityThread.java:4921)
12-05 18:23:15.407: E/AndroidRuntime(2378): at java.lang.reflect.Method.invokeNative(Native Method)
12-05 18:23:15.407: E/AndroidRuntime(2378): at java.lang.reflect.Method.invoke(Method.java:511)
12-05 18:23:15.407: E/AndroidRuntime(2378): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1036)
12-05 18:23:15.407: E/AndroidRuntime(2378): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:803)
12-05 18:23:15.407: E/AndroidRuntime(2378): at dalvik.system.NativeStart.main(Native Method)
代码：
private void createCamera() {
// Create an instance of Camera
mCamera = getCameraInstance();
// Setting the right parameters in the camera
Camera.Parameters params = mCamera.getParameters();
List<Size> allSizes = params.getSupportedPictureSizes();
Camera.Size size = allSizes.get(0); // get top size
for (int i = 0; i < allSizes.size(); i++) {
if (allSizes.get(i).width > size.width)
size = allSizes.get(i);
}
//set max Picture Size
params.setPictureSize(size.width, size.height);
params.setPictureFormat(PixelFormat.JPEG);
params.setJpegQuality(85);
mCamera.setParameters(params);
// Create our Preview view and set it as the content of our activity.
mPreview = new CameraPreview(TakePhotoActivity.this, mCamera);
FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
// Calculating the width of the preview so it is proportional.
float widthFloat = (float) (deviceHeight) * 4 / 3;
int width = Math.round(widthFloat);
// Resizing the LinearLayout so we can make a proportional preview. This
// approach is not 100% perfect because on devices with a really small
// screen the the image will still be distorted - there is place for
// improvment.
RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(width, deviceHeight);
preview.setLayoutParams(layoutParams);
// Adding the camera preview after the FrameLayout and before the button
// as a separated element.
preview.addView(mPreview, 0);
}
@Override
protected void onResume() {
super.onResume();
// Test if there is a camera on the device and if the SD card is
// mounted.
if (!checkCameraHardware(this)) {
finish();
} else if (!checkSDCard()) {
finish();
}
// Creating the camera
createCamera();
// Register this class as a listener for the accelerometer sensor
sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER), SensorManager.SENSOR_DELAY_NORMAL);
}
@Override
protected void onPause() {
super.onPause();
// release the camera immediately on pause event
releaseCamera();
// removing the inserted view - so when we come back to the app we
// won't have the views on top of each other.
preview.removeViewAt(0);
}
private void releaseCamera() {
if (mCamera != null) {
mCamera.stopPreview();
mCamera.setPreviewCallback(null);
mCamera.release(); // release the camera for other applications
mCamera = null;
}
}
/** Check if this device has a camera */
private boolean checkCameraHardware(Context context) {
if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
// this device has a camera
return true;
} else {
// no camera on this device
return false;
}
}
private boolean checkSDCard() {
boolean state = false;
String sd = Environment.getExternalStorageState();
if (Environment.MEDIA_MOUNTED.equals(sd)) {
state = true;
}
return state;
}
/**
* A safe way to get an instance of the Camera object.
*/
public static Camera getCameraInstance() {
Camera c = null;
try {
// attempt to get a Camera instance
c = Camera.open();
} catch (Exception e) {
// Camera is not available (in use or does not exist)
}
// returns null if camera is unavailable
return c;
}
private PictureCallback mPicture = new PictureCallback() {
public void onPictureTaken(byte[] data, Camera camera) {
// Replacing the button after a photho was taken.
linearLayout1.setVisibility(View.GONE);
linearLayout2.setVisibility(View.VISIBLE);
File directory = new File(Environment.getExternalStoragePublicDirectory
(Environment.DIRECTORY_PICTURES)
+"/Data/" + stringFolderName);
fileName = String.format("%d.jpg", System.currentTimeMillis());
File outFile = new File(directory, fileName);
try {
FileOutputStream purge = new FileOutputStream(outFile);
purge.write(data);
purge.close();
} catch (FileNotFoundException e) {
Log.d("DG_DEBUG", "File not found: " + e.getMessage());
} catch (IOException e) {
Log.d("DG_DEBUG", "Error accessing file: " + e.getMessage());
}
String cPath = Environment.getExternalStoragePublicDirectory
(Environment.DIRECTORY_PICTURES)
+"/Data/" + stringFolderName + "/"+ fileName;
Bitmap bMap= BitmapFactory.decodeFile(cPath);
Bitmap out = Bitmap.createScaledBitmap(bMap, 1024, 768, true);
//Bitmap adjustedBitmap = Bitmap.createBitmap(out, 0, 0, 1024, 768, matrix, true);
Log.d("image-name:-", fileName);
File resizedFile = new File(directory, fileName);
OutputStream fOut=null;
try {
fOut = new BufferedOutputStream(new FileOutputStream(resizedFile));
out.compress(Bitmap.CompressFormat.JPEG, 85, fOut);
fOut.flush();
fOut.close();
bMap.recycle();
out.recycle();
} catch (Exception e) { // TODO
}
// Adding Exif data for the orientation. For some strange reason the
// ExifInterface class takes a string instead of a file.
try {
exif = new ExifInterface(directory + "/"+fileName);
exif.setAttribute(ExifInterface.TAG_ORIENTATION, "" + orientation);
exif.saveAttributes();
} catch (IOException e) {
e.printStackTrace();
}
}
};
答案 0 :(得分：7)
尝试此代码并尝试在后台线程而不是UI中保存图像或视频
private PictureCallback mPicture = new PictureCallback() {
@Override
public void onPictureTaken(final byte[] data, Camera camera) {
final File pictureFile = getOutputMediaFile();
if (pictureFile == null) {
return;
}
Thread thread = new Thread() {
@Override
public void run() {
try {
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.close();
} catch (Exception e) {
e.printStackTrace();
}
}
};
thread.start();
}
};
private File getOutputMediaFile() {
File mediaStorageDir = new File(
Environment.getExternalStorageDirectory(),
"/Images");
if (!mediaStorageDir.exists()) {
if (!mediaStorageDir.mkdirs()) {
Log.d("Camera", "failed to create directory");
return null;
}
}
// Create a media file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss")
.format(new Date());
File mediaFile;
String image_path = mediaStorageDir.getPath() + File.separator
+ "IMG_" + timeStamp + ".jpg";
mediaFile = new File(image_path);
return mediaFile;
}
答案 1 :(得分：6)
未创建数据时。您无法使用位图。
这意味着需要一点时间来创建image.so bitmapcreate 返回null。
我认为PictureCallback像线程一样运行
解决此问题。更改此代码
Bitmap bMap= BitmapFactory.decodeFile(cPath);
Bitmap out = Bitmap.createScaledBitmap(bMap, 1024, 768, true);
到
Bitmap bMap = BitmapFactory.decodeByteArray(data, 0,.length);
Bitmap out = Bitmap.createScaledBitmap(bMap, 1024, 768, true);
该代码将 byte [] 转换为位图（参见picturecallback中的数据）;
相机API参考：Camera API tutorials