显示从SD卡到ImageView的照片

Question

我一直在尝试不同的东西，我可以将照片保存在用相机拍摄的SD卡中（非意图）但不能从SD卡中取出相同的照片并将其放在ImageView中。我总是得到一个Null指针Exception。

不知道遗失了什么，希望有人可以帮助我：

    PictureCallback jpegCallback = new PictureCallback() {
    public void onPictureTaken(byte[] data, Camera camera) {
        // Save the image JPEG data to the SD card
        FileOutputStream fos = null;
        String fileName = "";
        try {
            fileName = "/mnt/sdcard/DCIM/MyPicture.jpg";
            fos = new FileOutputStream(fileName);
            fos.write(data);

            fos.close();
            Toast.makeText(getBaseContext(), "Image saved:" ,
                     Toast.LENGTH_LONG).show();
        } catch (FileNotFoundException e) {
            Log.e(TAG, "File Note Found", e);
            Toast.makeText(getBaseContext(), "Image couldn't be saved.",
                     Toast.LENGTH_LONG).show();
        } catch (IOException e) {
            Log.e(TAG, "IO Exception", e);
            Toast.makeText(getBaseContext(), "Image couldn't be saved.",
                     Toast.LENGTH_LONG).show();
        }
        Bitmap bitmap = BitmapFactory.decodeFile(fileName);
        Log.d(TAG, fileName);
        mImageView.setImageBitmap(bitmap);
    }
};

我也试过了：

    try {
        Bitmap picture = BitmapFactory.decodeFile(Environment.getExternalStorageDirectory()
                + "/DCIM/MyPhoto.jpg");
        mImageView.setImageBitmap(picture);
    } catch (Exception e) {
        Log.e("Error reading file", e.toString());
    }
}

它会保存图片，但在尝试将图像放入ImageView时说“读取文件时出错”

logcat的：

DDMS：

对不起大家的头疼......我忘了把mImageView =（Imageview）findViewById（R.id.imageView1）;

我是一场灾难： - ）

Answer 1

试试这个，

        try {
            Bitmap picture = BitmapFactory.decodeFile(Environment.getExternalStorageDirectory().getPath()+"/DCIM/MyPhoto.jpg");
            Log.v("Path", Environment.getExternalStorageDirectory().getPath()+"/DCIM/MyPhoto.jpg");
            mImageView.setImageBitmap(picture);
        } catch (Exception e) {
            Log.e("Error reading file", e.toString());
        }

还要检查您的imageview mImageView是否已初始化

Answer 2

使用它。它会对你有帮助。

public class LoadImagesFromSDCard  extends AsyncTask<String, Void, Void> {

    private ProgressDialog Dialog = new ProgressDialog(CameraPhotoCapture.this);

    Bitmap mBitmap;

    protected void onPreExecute() {
        /****** NOTE: You can call UI Element here. *****/

        //UI Element
        Dialog.setMessage("Loading image from Sdcard..");
        Dialog.show();
    }

    // Call after onPreExecute method
    protected Void doInBackground(String... urls) {

        Bitmap bitmap = null;
        Bitmap newBitmap = null;
        Uri uri = null;       


            try {

                /**  Uri.withAppendedPath Method Description
                * Parameters
                *    baseUri  Uri to append path segment to 
                *    pathSegment  encoded path segment to append 
                * Returns
                *    a new Uri based on baseUri with the given segment appended to the path
                */

                uri = Uri.withAppendedPath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, "" + urls[0]);

                /**************  Decode an input stream into a bitmap. *********/
                bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(uri));

                if (bitmap != null) {

                    /********* Creates a new bitmap, scaled from an existing bitmap. ***********/

                    newBitmap = Bitmap.createScaledBitmap(bitmap, 170, 170, true); 

                    bitmap.recycle();

                    if (newBitmap != null) {

                        mBitmap = newBitmap;
                    }
                }
            } catch (IOException e) {
                //Error fetching image, try to recover

                /********* Cancel execution of this task. **********/
                cancel(true);
            }

        return null;
    }

    protected void onPostExecute(Void unused) {

        // NOTE: You can call UI Element here.

        // Close progress dialog
        Dialog.dismiss();

        if(mBitmap != null)
          showImg.setImageBitmap(mBitmap);
    }
}