如何从Android上的摄像头获取位图? [英] How can i get bitmap from camera on android?
本文介绍了如何从Android上的摄像头获取位图?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
代码:
public void startCameraActivity(){
Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
if (cameraIntent.resolveActivity(getActivity().getPackageManager()) != null) {
startActivityForResult(cameraIntent, 1000);
}
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
if(resultCode == Activity.RESULT_OK) {
if (requestCode == 1000){
File photo = new File(Environment.getExternalStorageDirectory(), ".camera.jpg");
OutputStream out = null;
String imagePath = data.getData().getPath();
Bitmap image = BitmapFactory.decodeFile(imagePath);
ExifInterface exif = null;
try {
exif = new ExifInterface(imagePath);
int exifOrientation = exif.getAttributeInt(
ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);
int exifDegree = exifOrientationToDegrees(exifOrientation);
image = rotate(image, exifDegree);
photo.createNewFile();
out = new FileOutputStream(Environment.getExternalStorageDirectory());
image.compress(Bitmap.CompressFormat.PNG, 100, out);
out.close();
} catch (IOException e) {
Toast.makeText(getContext(), "hello error", Toast.LENGTH_LONG).show();
}
returnUri = Uri.fromFile(photo);
}
Glide.with(this)
.load(returnUri)
.into(mImageview);
}
}
用于旋转图像
public int exifOrientationToDegrees(int exifOrientation)
{
if(exifOrientation == ExifInterface.ORIENTATION_ROTATE_90)
{return 90;}
else if(exifOrientation == ExifInterface.ORIENTATION_ROTATE_180)
{return 180;}
else if(exifOrientation == ExifInterface.ORIENTATION_ROTATE_270)
{return 270;}
return 0;
}
public Bitmap rotate(Bitmap bitmap, int degrees)
{
if(degrees != 0 && bitmap != null)
{
Matrix m = new Matrix();
m.setRotate(degrees, (float) bitmap.getWidth() / 2,
(float) bitmap.getHeight() / 2);
try
{
Bitmap converted = Bitmap.createBitmap(bitmap, 0, 0,
bitmap.getWidth(), bitmap.getHeight(), m, true);
if(bitmap != converted)
{
bitmap.recycle();
bitmap = converted;
}
}
catch(OutOfMemoryError ex)
{
}
}
return bitmap;
}
我编写了一个从相机获取图片的代码.
I made a code that get picture from camera.
但是来自相机的图片的方向不正确.
But that picture which has came from camera has incorrect direction.
因此，我搜索了旋转该图像.
So i searched to rotate that image.
但以上代码不起作用.
哪里有问题? 我该如何解决?
Where is problem? How can i fix it?
Android显示器说
Android monitor says
java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=66536, result=-1, data=Intent { act=inline-data dat=content://media/external/images/media/8464 flg=0x1 (has extras) }} to activity {~~!@.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.graphics.Bitmap.compress(android.graphics.Bitmap$CompressFormat, int, java.io.OutputStream)' on a null object reference
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.graphics.Bitmap.compress(android.graphics.Bitmap$CompressFormat, int, java.io.OutputStream)' on a null object reference
编辑完整日志
11-03 11:21:42.060 16104-16104/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.keepair.www.pinair, PID: 16104
java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=66536, result=-1, data=Intent { act=inline-data dat=content://media/external/images/media/8465 flg=0x1 (has extras) }} to activity {com.keepair.www.pinair/com.keepair.www.pinair.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.graphics.Bitmap.compress(android.graphics.Bitmap$CompressFormat, int, java.io.OutputStream)' on a null object reference
at android.app.ActivityThread.deliverResults(ActivityThread.java:4173)
at android.app.ActivityThread.handleSendResult(ActivityThread.java:4216)
at android.app.ActivityThread.access$1400(ActivityThread.java:181)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1523)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:6117)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.graphics.Bitmap.compress(android.graphics.Bitmap$CompressFormat, int, java.io.OutputStream)' on a null object reference
at com.keepair.www.pinair.GreenFragment.onActivityResult(GreenFragment.java:296)
at android.support.v4.app.FragmentActivity.onActivityResult(FragmentActivity.java:165)
at android.app.Activity.dispatchActivityResult(Activity.java:6632)
at android.app.ActivityThread.deliverResults(ActivityThread.java:4169)
at android.app.ActivityThread.handleSendResult(ActivityThread.java:4216)
at android.app.ActivityThread.access$1400(ActivityThread.java:181)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1523)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:6117)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
at
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
推荐答案
这是我写的，您可以尝试一下.
Here is what I have written, you can try it.
public static final int PICK_USER_PROFILE_IMAGE = 1000;
public void startCameraActivity(){
Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
if (cameraIntent.resolveActivity(getActivity().getPackageManager()) != null) {
startActivityForResult(cameraIntent, PICK_USER_PROFILE_IMAGE);
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RESULT_OK) {
if (requestCode == Constants.PICK_USER_PROFILE_IMAGE) {
if (resultCode == RESULT_OK) {
Bitmap bmp = ImagePicker.getImageFromResult(this, resultCode, data);
//your compressed rotated bitmap here
}
}
}
}
下面是ImagePicker类，它具有用于完成工作的一系列方法
Below is the class ImagePicker that have series of methods to do your work
public class ImagePicker {
private static final int DEFAULT_MIN_WIDTH_QUALITY = 400; // min pixels
private static final String TAG = "ImagePicker";
private static final String TEMP_IMAGE_NAME = "tempImage";
public static int minWidthQuality = DEFAULT_MIN_WIDTH_QUALITY;
public static Bitmap getImageFromResult(Context context, int resultCode,
Intent imageReturnedIntent) {
Log.d(TAG, "getImageFromResult, resultCode: " + resultCode);
Bitmap bm = null;
File imageFile = getTempFile(context);
if (resultCode == Activity.RESULT_OK) {
Uri selectedImage;
boolean isCamera = (imageReturnedIntent == null ||
imageReturnedIntent.getData() == null ||
imageReturnedIntent.getData().equals(Uri.fromFile(imageFile)));
if (isCamera) { /** CAMERA **/
selectedImage = Uri.fromFile(imageFile);
} else { /** ALBUM **/
selectedImage = imageReturnedIntent.getData();
}
Log.d(TAG, "selectedImage: " + selectedImage);
bm = getImageResized(context, selectedImage);
int rotation = getRotation(context, selectedImage, isCamera);
bm = rotate(bm, rotation);
}
return bm;
}
private static Bitmap decodeBitmap(Context context, Uri theUri, int sampleSize) {
BitmapFactory.Options options = new BitmapFactory.Options();
options.inSampleSize = sampleSize;
AssetFileDescriptor fileDescriptor = null;
try {
fileDescriptor = context.getContentResolver().openAssetFileDescriptor(theUri, "r");
} catch (FileNotFoundException e) {
e.printStackTrace();
}
Bitmap actuallyUsableBitmap = BitmapFactory.decodeFileDescriptor(
fileDescriptor.getFileDescriptor(), null, options);
Log.d(TAG, options.inSampleSize + " sample method bitmap ... " +
actuallyUsableBitmap.getWidth() + " " + actuallyUsableBitmap.getHeight());
return actuallyUsableBitmap;
}
/**
* Resize to avoid using too much memory loading big images (e.g.: 2560*1920)
**/
private static Bitmap getImageResized(Context context, Uri selectedImage) {
Bitmap bm = null;
int[] sampleSizes = new int[]{5, 3, 2, 1};
int i = 0;
do {
bm = decodeBitmap(context, selectedImage, sampleSizes[i]);
Log.d(TAG, "resizer: new bitmap width = " + bm.getWidth());
i++;
} while (bm.getWidth() < minWidthQuality && i < sampleSizes.length);
return bm;
}
private static int getRotation(Context context, Uri imageUri, boolean isCamera) {
int rotation;
if (isCamera) {
rotation = getRotationFromCamera(context, imageUri);
} else {
rotation = getRotationFromGallery(context, imageUri);
}
Log.d(TAG, "Image rotation: " + rotation);
return rotation;
}
private static int getRotationFromCamera(Context context, Uri imageFile) {
int rotate = 0;
try {
context.getContentResolver().notifyChange(imageFile, null);
ExifInterface exif = new ExifInterface(imageFile.getPath());
int orientation = exif.getAttributeInt(
ExifInterface.TAG_ORIENTATION,
ExifInterface.ORIENTATION_NORMAL);
switch (orientation) {
case ExifInterface.ORIENTATION_ROTATE_270:
rotate = 270;
break;
case ExifInterface.ORIENTATION_ROTATE_180:
rotate = 180;
break;
case ExifInterface.ORIENTATION_ROTATE_90:
rotate = 90;
break;
}
} catch (Exception e) {
e.printStackTrace();
}
return rotate;
}
public static int getRotationFromGallery(Context context, Uri imageUri) {
String[] columns = {MediaStore.Images.Media.ORIENTATION};
Cursor cursor = context.getContentResolver().query(imageUri, columns, null, null, null);
if (cursor == null) return 0;
cursor.moveToFirst();
int orientationColumnIndex = cursor.getColumnIndex(columns[0]);
return cursor.getInt(orientationColumnIndex);
}
private static Bitmap rotate(Bitmap bm, int rotation) {
if (rotation != 0) {
Matrix matrix = new Matrix();
matrix.postRotate(rotation);
Bitmap bmOut = Bitmap.createBitmap(bm, 0, 0, bm.getWidth(), bm.getHeight(), matrix, true);
return bmOut;
}
return bm;
}
private static File getTempFile(Context context) {
File imageFile = new File(context.getExternalCacheDir(), TEMP_IMAGE_NAME);
imageFile.getParentFile().mkdirs();
return imageFile;
}
}
ImagePicker类具有处理压缩和图像旋转的所有方法.
The ImagePicker Class have all the methods of handling compression as well as rotation of image.
希望这会有所帮助
这篇关于如何从Android上的摄像头获取位图?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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