从外部存储Android中读取图像/文件

Question

我正在尝试从外部存储加载图像.我设置权限,我尝试了不同的方式,但没有一个工作.

BitmapFactory.Options options = new BitmapFactory.Options();
    options.inPreferredConfig = Bitmap.Config.ARGB_8888;

    Bitmap bitmap = BitmapFactory.decodeFile(file.toString()); 

    tv.setImageBitmap(bitmap);

还有这个,

FileInputStream streamIn = new FileInputStream(file);
Bitmap bitmap = BitmapFactory.decodeStream(streamIn); 

    tv.setImageBitmap(bitmap);
        streamIn.close();

Answer 1

如果我有文件abc.jpg,sdcard那么:

String photoPath = Environment.getExternalStorageDirectory() + "/abc.jpg";

得到bitmap.

BitmapFactory.Options options = new BitmapFactory.Options();
options.inPreferredConfig = Bitmap.Config.ARGB_8888;
Bitmap bitmap = BitmapFactory.decodeFile(photoPath, options);

要么

Bitmap bitmap1 = BitmapFactory.decodeFile(photoPath);

为了避免内存不足错误我建议您使用以下代码...

BitmapFactory.Options options = new BitmapFactory.Options();
options.inSampleSize = 8;
final Bitmap b = BitmapFactory.decodeFile(photoPath, options);

为避免上述问题,您可以使用Picasso(适用于Android的强大图像下载和缓存库)

文档

如何？

Picasso.with(context).load("file:///android_asset/DvpvklR.png").into(imageView2);
Picasso.with(context).load(new File(...)).into(imageView3);

Answer 2

File sdCard = Environment.getExternalStorageDirectory();

File directory = new File (sdCard.getAbsolutePath() + "/Pictures");

File file = new File(directory, "image_name.jpg"); //or any other format supported

FileInputStream streamIn = new FileInputStream(file);

Bitmap bitmap = BitmapFactory.decodeStream(streamIn); //This gets the image

streamIn.close();