拍摄一张照片，然后将其显示到 ImageView

Question

我想拍一张照片并把它放在一个 imageView.I 已经设法打开相机，每次我拍一张照片它都会让我拍另一张照片。这是我的 onCreate 方法：

    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_camera);
    File photo = dispatchTakePictureIntent();
    ImageView imgView = (ImageView) findViewById(R.id.DisplayImageView);
    if(photo.exists()){
        Bitmap myBitmap = BitmapFactory.decodeFile(photo.getAbsolutePath());
        imgView.setImageBitmap(myBitmap);
    }
}

这是我的拍照方法：

    private File dispatchTakePictureIntent() {
    Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    File photoFile = null;
    // Ensure that there's a camera activity to handle the intent
    if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
        // Create the File where the photo should go
        try {
            photoFile = createImageFile();
        } catch (IOException ex) {
            // Error occurred while creating the File
            Toast.makeText(this, "Failed to create the image file!", Toast.LENGTH_SHORT).show();
        }
        // Continue only if the File was successfully created
        if (photoFile != null) {
            takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT,
                    Uri.fromFile(photoFile));
            startActivityForResult(takePictureIntent, REQUEST_TAKE_PHOTO);

        }
    }
    return photoFile;
}

我需要在拍完一张照片后从相机返回 activity 并查看它。我该怎么做？

Answer 1

好吧，在您的 Activity 中确实开始了 ActivityForResult 覆盖了以下方法

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == REQUEST_TAKE_PHOTO && resultCode == RESULT_OK) {
        Bundle extras = data.getExtras();
        Bitmap imageBitmap = (Bitmap) extras.get("data");
        mImageView.setImageBitmap(imageBitmap);
    }
}

将 mImageView 替换为您要显示图像的 ImageView

Answer 2

您需要覆盖 Activity 的 ActivityResult() 以获取图像并将其显示在 ImageView 中。从 Camera 获取图像时，您应该根据需要对图像进行采样，同时为了防止图像在 ImageView 中显示时旋转，您需要查找 Exif 参数。

这是 onActivityResult() 代码。

 @Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    try {
        if (resultCode == RESULT_OK && requestCode == Constants.REQUEST_TAKE_PHOTO) {

// in case of taking pic from camera, you have to define filepath already  and image get saved in that filepath you specified at the time when you started camera intent.So in your case it will be following

           String filePath=photoFile.getAbsolutePath(); //photofile is the same file you passed while starting camera intent.
            if (filePath != null) {
                int orientation = 0;
                private Bitmap imageBitmap;
                try {
                    ExifInterface exif = new ExifInterface(filePath);
                    orientation = exif.getAttributeInt(
                            ExifInterface.TAG_ORIENTATION, 1);
                } catch (IOException e) {
                    e.printStackTrace();
                }
                try {
                    final BitmapFactory.Options options = new BitmapFactory.Options();
                    options.inJustDecodeBounds = true;
                    BitmapFactory.decodeFile(filePath, options);
                    options.inSampleSize = calculateInSampleSize(
                            options, reqWidth, rewHeight);
                    options.inJustDecodeBounds = false;
                    imageBitmap = BitmapFactory.decodeFile(filePath,
                            options);
                    if (orientation == 6) {
                        Matrix matrix = new Matrix();
                        matrix.postRotate(90);
                        imageBitmap = Bitmap.createBitmap(imageBitmap,
                                0, 0, imageBitmap.getWidth(),
                                imageBitmap.getHeight(), matrix, true);
                    } else if (orientation == 8) {
                        Matrix matrix = new Matrix();
                        matrix.postRotate(270);
                        imageBitmap = Bitmap.createBitmap(imageBitmap,
                                0, 0, imageBitmap.getWidth(),
                                imageBitmap.getHeight(), matrix, true);
                    } else if (orientation == 3) {
                        Matrix matrix = new Matrix();
                        matrix.postRotate(180);
                        imageBitmap = Bitmap.createBitmap(imageBitmap,
                                0, 0, imageBitmap.getWidth(),
                                imageBitmap.getHeight(), matrix, true);
                    }
                } catch (OutOfMemoryError e) {
                    imageBitmap = null;
                    e.printStackTrace();
                } catch (Exception e) {
                    imageBitmap = null;
                    e.printStackTrace();
                }
            }
            if (imageBitmap != null) {
                // set this imageBitmap to your ImageView
            }
        }

    } catch (Exception e) {
        e.printStackTrace();
    }

}

这是采样函数

public static int calculateInSampleSize(BitmapFactory.Options options,
                                        int reqWidth, int reqHeight) {
    // Raw height and width of image
    final int height = options.outHeight;
    final int width = options.outWidth;
    int inSampleSize = 1;
    if (height > reqHeight || width > reqWidth) {
        final int halfHeight = height / 2;
        final int halfWidth = width / 2;
        while ((halfHeight / inSampleSize) > reqHeight
                && (halfWidth / inSampleSize) > reqWidth) {
            inSampleSize *= 2;
        }
    }
    return inSampleSize;
}

拍摄一张照片，然后将其显示到 ImageView

Taking one picture and then display it to a ImageView

camera

android