Question

我尝试从图库中显示位图。这是我的网址

file:///storage/emulated/0/DCIM/Camera/IMG_20161103_180603.jpg

我知道如何使用onActivityResult()获取位图，但我不知道如何获取位图

这是我的来源

 final ImageView imageView=(ImageView)findViewById(R.id.imageView);

        BitmapFactory.Options options = new BitmapFactory.Options();

        options.inPreferredConfig = Bitmap.Config.ARGB_8888;
        final Bitmap bitmap = BitmapFactory.decodeFile("file:///storage/emulated/0/DCIM/Camera/IMG_20161103_180603.jpg", options);
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                imageView.setImageBitmap(bitmap);
            }
        });

如何解决我的问题？

Answer 1

请参阅以下代码

 BitmapFactory.Options options = new BitmapFactory.Options();

            options.inPreferredConfig = Bitmap.Config.ARGB_8888;
            //Get our saved file into a bitmap object:
            File file = new File(Environment.getExternalStorageDirectory()+File.separator + "DCIM"+ File.separator + "Camera "+File.separator + "IMG_20161103_180603.jpg");
            Bitmap bitmap = BitmapFactory.decodeFile(file.getAbsolutePath(), options);
            imageView.setImageBitmap(bitmap);

Answer 2

由于无法在运行时处理大图像尺寸而导致同样的问题。用它来解决它。

// Decodes image and scales it to reduce memory consumption
public static Bitmap decodeFile(File f) {
    try {
        // Decode image size
        BitmapFactory.Options o = new BitmapFactory.Options();
        o.inJustDecodeBounds = true;
        BitmapFactory.decodeStream(new FileInputStream(f), null, o);

        // The new size we want to scale to
        final int REQUIRED_SIZE = 200;

        // Find the correct scale value. It should be the power of 2.
        int scale = 1;
        while (o.outWidth / scale / 2 >= REQUIRED_SIZE &&
                o.outHeight / scale / 2 >= REQUIRED_SIZE) {
            scale *= 2;
        }

        // Decode with inSampleSize
        BitmapFactory.Options o2 = new BitmapFactory.Options();
        o2.inSampleSize = scale;
        return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    }
    return null;
}

使用https://stackoverflow.com/a/20559418/3758972

检索File f

只需将您想要的缩略图大小（通常是您的imageview的大小）放在REQUIRED_SIZE中即可。它会为您提供一个缩放图像，您可以将其设置为imageview。

Answer 3

decodeFile( "file:///storage/emulated/0/DCIM/Camera/IMG_20161103_180603.jpg

更改为：

decodeFile( "/storage/emulated/0/DCIM/Camera/IMG_20161103_180603.jpg

无法在ImageView中显示位图

3 个答案: