从Firebase下载图像仅在android中有效一次

Question

我在主要活动中将图像上传到firebase存储，并在recyclerview显示该图像。 在我的“ recycler视图中单击图像后，我将转到fullimageactivity并传递该图像的url 。 下面是fullimageactivity的代码，其中包含一个按钮，单击该按钮，我会将图像下载到用户的手机中

public class FullImageActivity extends AppCompatActivity {
    private ImageView imageView;
    Button button;
    private static final int WATER_REMINDER_NOTIFICATION_ID = 1138;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_full_image);
        imageView = (ImageView) findViewById(R.id.fullimageactivityimageview);
        button = (Button) findViewById(R.id.button);
        String image = getIntent().getStringExtra("Image");
        Glide.with(getApplicationContext()).load(image).into(imageView);


        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                    if (checkSelfPermission(android.Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED
                            && checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED
                            ) {
                        requestPermissions(new String[]{android.Manifest.permission.READ_EXTERNAL_STORAGE,
                                Manifest.permission.WRITE_EXTERNAL_STORAGE}, 0);
                    }

                } else {
                    downloadImage();

                }
            }});

    }


    private class DownloadImage extends AsyncTask<Object, Object, Bitmap> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();

        }

        @Override
        protected Bitmap doInBackground(Object... URL) {
            Bitmap bitmapimage = null;
            String root = Environment.getExternalStorageDirectory().toString();
            File myDir = new File(root + "/saved_images");
            myDir.mkdirs();
            Random generator = new Random();
            int n = 10000;
            n = generator.nextInt(n);
            String fname = "Image-" + n + ".jpg";
            File file = new File(myDir, fname);
            if (file.exists()) file.delete();
            try {
                bitmapimage = Glide.with(getApplicationContext()).load(URL[0]).asBitmap().into(100, 100).get();
                FileOutputStream out = new FileOutputStream(file);
                bitmapimage.compress(Bitmap.CompressFormat.JPEG, 90, out);
                out.flush();
                out.close();


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

        @Override
        protected void onPostExecute(Bitmap result) {

        }


    }

    private PendingIntent contentIntent(Context context) {

        //  Intent startActivityIntent = new Intent(Intent.ACTION_VIEW, Uri.parse(getIntent().getStringExtra("Image")));

        Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse("content://media/internal/images/media"));

        PendingIntent contentIntent =
                PendingIntent.getActivity(context.getApplicationContext(),
                        id,
                        intent,
                        PendingIntent.FLAG_UPDATE_CURRENT
                );

        return contentIntent;
    }

    private Bitmap largeIcon(Context context) {
        Resources res = context.getResources();
        Bitmap largeIcon = BitmapFactory.decodeResource(res, R.mipmap.notification);
        return largeIcon;
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode == 0) {
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED && grantResults[1] == PackageManager.PERMISSION_GRANTED) {
                downloadImage();
            }

        }
    }

    public void downloadImage() {
        Toast.makeText(getApplicationContext(), "Hi", Toast.LENGTH_SHORT).show();

        new DownloadImage().execute(getIntent().getStringExtra("Image"));
        android.support.v4.app.NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(getApplicationContext())
                .setColor(ContextCompat.getColor(getApplicationContext(), R.color.colorPrimary))
                .setSmallIcon(R.mipmap.notification)
                .setLargeIcon(largeIcon(getApplicationContext()))
                .setContentTitle(getString(R.string.imagedownloaded))
                .setContentIntent(contentIntent(getApplicationContext()))
                .setAutoCancel(true);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
            notificationBuilder.setPriority(Notification.PRIORITY_HIGH);
        }

        NotificationManager notificationManager = (NotificationManager)
                getApplicationContext().getSystemService(Context.NOTIFICATION_SERVICE);

        notificationManager.notify(WATER_REMINDER_NOTIFICATION_ID, notificationBuilder.build());

    }

}

当我第一次单击下载按钮时，图像已正确下载。当我返回mainactivity并选择其他图像并单击它时，我将移至fullimageactivity ，而单击fullimageactivity图像的按钮将不会下载。 简而言之，它仅下载第一个图像，然后不再下载其他图像。请帮我解决我做错的事情吗？

Answer 1

如果您的设备包含marshmello，则会出现此问题，因为在您第一次请求权限时，但是一旦授予了权限，便不会调用第二次downloadimage（），因此请按如下所示编辑代码：

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                if (checkSelfPermission(android.Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED
                        && checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED
                        ) {
                    requestPermissions(new String[]{android.Manifest.permission.READ_EXTERNAL_STORAGE,
                            Manifest.permission.WRITE_EXTERNAL_STORAGE}, 0);
                }else {
                downloadImage();
            } else {
                downloadImage();

            }