Android从drawable创建文件

Question

有没有办法从可绘制的图像创建文件以通过MultypartEntity 发送它？我总是出错。

fileUri =  Uri.parse("android.resource://com.wellbread/drawable/placeholder_avatar.png");
mCurrentPhotoPath = fileUri.toString();


 java.io.FileNotFoundException: android.resource:/com.wellbread/drawable/placeholder_avatar.png: open failed: ENOENT (No such file or directory)
08-25 12:01:53.134    3663-3684/? W/System.err﹕ at libcore.io.IoBridge.open(IoBridge.java:456)

Answer 1

试试下面的示例代码：

        Drawable drawable = getResources().getDrawable(R.drawable.ic_action_home);
        if (drawable != null) {
            Bitmap bitmap = ((BitmapDrawable) drawable).getBitmap();
            ByteArrayOutputStream stream = new ByteArrayOutputStream();
            bitmap.compress(Bitmap.CompressFormat.PNG, 100, stream);
            final byte[] bitmapdata = stream.toByteArray();
            String url = "http://10.0.2.2/api/fileupload";
            MultipartEntityBuilder builder = MultipartEntityBuilder.create();
            builder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);

            // Add binary body
            if (bitmapdata != null) {
                ContentType contentType = ContentType.create("image/png");
                String fileName = "ic_action_home.png";
                builder.addBinaryBody("file", bitmapdata, contentType, fileName);
                httpEntity = builder.build();
                ...
            }
        ...
        }

Answer 2

试试这个：

try
        {
        File f=new File("file name");
       InputStream inputStream = getResources().openRawResource(id); // id drawable
        OutputStream out=new FileOutputStream(f);
        byte buf[]=new byte[1024];
        int len;
        while((len=inputStream.read(buf))>0)
        out.write(buf,0,len);
        out.close();
        inputStream.close();
        }
        catch (IOException e){}
        } 

Answer 3

您可以使用以下代码从可绘制资源中打开 InputStream：

     try 
        { 
        File f=new File("your file name");
//id is some like R.drawable.b_image
        InputStream inputStream = getResources().openRawResource(id);
        OutputStream out=new FileOutputStream(f);
        byte buf[]=new byte[1024];
        int len;
        while((len=inputStream.read(buf))>0)
        out.write(buf,0,len);
        out.close();
        inputStream.close();
        } 
        catch (IOException e){}
        } 

Answer 4

你必须从drawable中获取Bitmap：

public static Bitmap decodeAndSetWidthHeight(Resources res, int resId, int reqWidth, int reqHeight){
        Bitmap btm = BitmapHelper.decodeSampledBitmapFromResource(res, resId, reqWidth, reqHeight);
        return decodeAndSetWidthHeight(btm, reqWidth, reqHeight);
    }

然后你可以从位图创建文件

    public static File bitmapToFile(Bitmap bitmap){
        File outFile = FileHelper.getImageFilePNG();
        FileOutputStream out = null;
        try {
            out = new FileOutputStream(outFile);
            bitmap.compress(Bitmap.CompressFormat.PNG, 100, out);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } finally {
            try {
                if (out != null) {
                    out.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        return outFile;
    }

UPDATE（抱歉，忘记提供一些方法）：

public static File getImageFilePNG() {
    File sdCard = Environment.getExternalStorageDirectory();
    File dir = new File(sdCard.getAbsolutePath() + "/any name folder");
    dir.mkdirs();

    String fileName = String.format("%d.png", System.currentTimeMillis());
    return new File(dir, fileName);
}


 public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId,
                                                     int reqWidth, int reqHeight) {

    // First decode with inJustDecodeBounds=true to check dimensions
    final BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    BitmapFactory.decodeResource(res, resId, options);

    // Calculate inSampleSize
    options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
    Log.d("ANT", "options.inSampleSize : " + options.inSampleSize);

    // Decode bitmap with inSampleSize set
    options.inJustDecodeBounds = false;
    return BitmapFactory.decodeResource(res, resId, options);
}

 public static Bitmap decodeAndSetWidthHeight(Bitmap btm, int reqWidth, int reqHeight){
    Matrix m = new Matrix();
    RectF inRect = new RectF(0, 0, btm.getWidth(), btm.getHeight());
    RectF outRect = new RectF(0, 0, reqWidth, reqHeight);
    m.setRectToRect(inRect, outRect, Matrix.ScaleToFit.FILL);
    float[] values = new float[9];
    m.getValues(values);

    return Bitmap.createScaledBitmap(btm, (int) (btm.getWidth() * values[0]), (int) (btm.getHeight() * values[4]), true);
}