从图像 URI 中获取 base64 字符串

Question

我有一个图像的 content:// URI，我想将它转换为 base64。 我不知道该怎么做。

这是我的代码：

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if(requestCode==123 && resultCode==RESULT_OK) {
        Uri selectedfile = data.getData(); //The uri with the location of the file
        if (selectedfile != null) {
            Log.e("image", selectedfile.toString());
        }
    }
}

Answer 1

您可以使用 2 个步骤来完成。

1- URI 到位图的转换：

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if(requestCode==123 && resultCode==RESULT_OK) {
        Uri selectedfile = data.getData(); //The uri with the location of the file
        if (selectedfile != null) {
           Bitmap bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), selectedfile);
        }
    }
}

2-位图到 Base64 字符串转换：

ByteArrayOutputStream outputStream = new ByteArrayOutputStream();  
bitmap.compress(Bitmap.CompressFormat.PNG, 100, outputStream);
byte[] byteArray = outputStream.toByteArray();

String encodedString = Base64.encodeToString(byteArray, Base64.DEFAULT);

结果：

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if(requestCode==123 && resultCode==RESULT_OK) {
        Uri selectedfile = data.getData(); //The uri with the location of the file
        if (selectedfile != null) {
           Bitmap bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), selectedfile);

           ByteArrayOutputStream outputStream = new ByteArrayOutputStream();  
           bitmap.compress(Bitmap.CompressFormat.PNG, 100, outputStream);
           byte[] byteArray = outputStream.toByteArray();

           //Use your Base64 String as you wish
           String encodedString = Base64.encodeToString(byteArray, Base64.DEFAULT);
        }
    }
}