Imageview 拒绝显示图像

Question

我已经尝试了很多不同的方法来让图片显示在我的 imageView 中，但它只是拒绝这样做。我不知道发生了什么。我的应用需要做的不仅仅是拍照并展示它。基本上所有这些代码都直接来自Android website。

private File createImageFile() throws IOException 
{
    // Create an image file name
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
    String imageFileName = "JPEG_" + timeStamp + "_";
    File storageDir = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
    File image = File.createTempFile(
        imageFileName,  /* prefix */
        ".jpg",         /* suffix */
        storageDir      /* directory */
    );

    // Save a file: path for use with ACTION_VIEW intents
    mCurrentPhotoPath = "file:" + image.getAbsolutePath();
    return image;
}

private void dispatchTakePictureIntent() 
{
    // Create the File where the photo should go
    File photoFile = null;
    try {
        photoFile = createImageFile();
   //   Log.d("myTag", "MADE IMAGE FILE");
   } catch (IOException ex) {
   //   Log.d("myTag", "ERROR CREATING IMAGE FILE");
   }
   // Continue only if the File was successfully created
    if (photoFile != null) {
        Uri photoURI = FileProvider.getUriForFile(this,"com.company.app.fileprovider.READ",photoFile);
        Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoURI);
     // Log.d("myTag", "PUTEXTRA");
        startActivityForResult(takePictureIntent, REQUEST_TAKE_PHOTO);
     // Log.d("myTag", "ABOUTTOSTARTACTIVITY");
    }
}

protected void onActivityResult(int requestCode, int resultCode, Intent data)
{
    if (requestCode == REQUEST_TAKE_PHOTO) {
        setPic();
    }
}

我在 setPic() 中唯一能注意到的是 mImageView.getWidth() 和 getHeight() 返回 0 和错误。我尝试在不缩放的情况下显示图像，但结果仍然相同（或没有结果）。我也试过 getMeasuredWidth() 并没有错误，但仍然..没有图像。

private void setPic() {
// Get the dimensions of the View
int targetW = mImageView.getWidth(); //getMeasuredWidth()
int targetH = mImageView.getHeight(); //getMeasuredHeight()

// Get the dimensions of the bitmap
BitmapFactory.Options bmOptions = new BitmapFactory.Options();
bmOptions.inJustDecodeBounds = true;
BitmapFactory.decodeFile(mCurrentPhotoPath, bmOptions);
int photoW = bmOptions.outWidth;
int photoH = bmOptions.outHeight;

// Determine how much to scale down the image
// int scaleFactor = Math.min(photoW/targetW, photoH/targetH);

//Decode the image file into a Bitmap sized to fill the View
bmOptions.inJustDecodeBounds = false;
//bmOptions.inSampleSize = scaleFactor;
bmOptions.inPurgeable = true;

Bitmap bitmap = BitmapFactory.decodeFile(mCurrentPhotoPath, bmOptions);
mImageView.setImageBitmap(bitmap);

}

我的 mCurrentPhotoPath 不再为空。图像仍然不显示。我拍的所有照片都在我手机的画廊里，所以它正在保存。 有问题的 imageView 的 xml 在这里：

ImageView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/main_picture"
    android:paddingLeft="250dp"
    android:paddingBottom="250dp"
    android:adjustViewBounds="true"
    android:layout_alignParentBottom="true"
    android:layout_toLeftOf="@+id/home_button"
    android:layout_marginRight="41dp"
    android:layout_marginEnd="41dp" />

我的 onCreate 中有以下行：

mImageView = (ImageView) findViewById(R.id.main_picture);

Answer 1

如果您需要用相机拍照并在图像视图中显示（这是我的理解），我认为这可以帮助您

Capture Image from Camera and Display in Activity

编辑：把所有对我有用的代码

调用意图

 private void dispatchTakePictureIntent() {
    Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    // Ensure that there's a camera activity to handle the intent
    if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
        // Create the File where the photo should go
        File photoFile = null;
        try {
            photoFile = createImageFile();
        } catch (IOException ex) {
            // Error occurred while creating the File

        }
        // Continue only if the File was successfully created
        if (photoFile != null) {

            Uri photoURI = Uri.fromFile(photoFile);
            takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoURI);
            startActivityForResult(takePictureIntent, REQUEST_TAKE_PHOTO);
        }
    }
}

创建文件的方法

private File createImageFile() throws IOException {
    // Create an image file name
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
    String imageFileName = "JPEG_" + timeStamp;
    File storageDir = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
    File image = File.createTempFile(
            imageFileName,  /* prefix */
            ".jpg",         /* suffix */
            storageDir      /* directory */
    );

    // Save a file: path for use with ACTION_VIEW intents
    mCurrentPhotoPath = "file:" + image.getAbsolutePath();
    return image;
}

保存和恢复activity状态的方法

@Override
public void onSaveInstanceState(Bundle savedInstanceState) {

    //savedInstanceState.putString("filePath", mCurrentPhotoPath);
    savedInstanceState.putString("filePath", mCurrentPhotoPath);
    BitmapDrawable drawable = (BitmapDrawable) img.getDrawable();
    if(drawable!= null) {
        Bitmap bitmap = drawable.getBitmap();
        savedInstanceState.putParcelable("image", bitmap);
    }

    // Always call the superclass so it can save the view hierarchy state
    super.onSaveInstanceState(savedInstanceState);
}

@Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
    super.onRestoreInstanceState(savedInstanceState);

    if(savedInstanceState != null) {
        mCurrentPhotoPath= savedInstanceState.getString("filePath");
        Bitmap bitmap = savedInstanceState.getParcelable("image");
        img.setImageBitmap(bitmap);
    }
}

活动结果（您的 setPic() 方法）

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {

        try {
            Bitmap mImageBitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), Uri.parse(mCurrentPhotoPath));
            img.setImageBitmap(mImageBitmap);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

希望对您有所帮助。

Answer 2

试试这个对我有用

final BitmapFactory.Options options = new BitmapFactory.Options();
            options.inSampleSize = 0;
            File imageFile = new File("/sdcard/Cyclops/cyclops.jpg");
            bitmap = BitmapFactory.decodeFile(imageFile.getAbsolutePath(), options);
           imageView.setImageBitmap(bitmap);