Question

我读了很多主题，其中位图通过decodeFile和createScaledBitmap调整大小。但我想更改此文件，而不创建额外的位图或文件。这意味着，就在我打开这个文件时，位图会更小/更大。有可能吗？

编辑：具体来说，我有jpeg文件，我将压缩这些文件，在制作zip之前我设置了图像大小（在zip文件中）。

Answer 1

如果您只想将其作为自身的较小版本打开，则可以使用BitmapFactory.Options.inSampleSize来减少负载大小。如果您想实际调整图像大小并将其重新保存到文件系统，您需要在AsyncTask中执行此操作，

类似的东西：

public class ImageResizerTask extends AsyncTask<Integer, Void, Bitmap> {

    Bitmap mBitmap;
    String filePath;
    Context mContext;
    Activity mCallBack;
    //ProgressDialog pd;

    public ImageResizerTask(Context context, String path,
            Activity callBack) {

        mContext = context;
        filePath = path;
        mBitmap = BitmapFactory.decodeFile(filePath);
        mCallBack = callBack;
    }
    @Override
    protected void onPreExecute() {


    }

    @Override
    protected Bitmap doInBackground(Integer... params) {
        // TODO Auto-generated method stub
        resize(mBitmap);
        return mBitmap;
    }

    @Override
    protected void onPostExecute(Bitmap bitmap) {
        //pd.dismiss();
        bitmap.recycle();
        mCallBack.onImageResized(filePath);

    }


    private void resize(Bitmap tmp) {

        final Bitmap bitmap = Bitmap.createBitmap(500, 500,
                Bitmap.Config.ARGB_8888);

        final Canvas canvas = new Canvas(bitmap);

        Log.v("TMPBMP",
                "temp bmp width:" + tmp.getWidth() + " height:"
                        + tmp.getHeight());

        if (tmp.getWidth() < tmp.getHeight()) {
            final int width = (int) (1f * tmp.getWidth() / tmp.getHeight() * 500);

            final int height = 500;
            final Bitmap scaled = Bitmap.createScaledBitmap(tmp, width, height,
                    false);
            final int leftOffset = (bitmap.getWidth() - scaled.getWidth()) / 2;
            final int topOffset = 0;
            canvas.drawBitmap(scaled, leftOffset, topOffset, null);
        } else {
            final int width = 500;
            final int height = (int) (1f * tmp.getHeight() / tmp.getWidth() * 500);
            ;
            final Bitmap scaled = Bitmap.createScaledBitmap(tmp, width, height,
                    false);
            final int leftOffset = 0;
            final int topOffset = (bitmap.getHeight() - scaled.getHeight()) / 2;
            canvas.drawBitmap(scaled, leftOffset, topOffset, null);
        }

        FileOutputStream outStream;

        try {
            outStream = new FileOutputStream(filePath);

            try {
                bitmap.compress(Bitmap.CompressFormat.PNG, 100, outStream);
                outStream.flush();
                outStream.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }


    }


}

Answer 2

我不清楚，你想要获得什么，但这是一个调整图像文件大小的简单代码

    String your_file_path = "image.png";
    int set_scale_your_need  = 2;
    //getting your image size
    BitmapFactory.Options o = new BitmapFactory.Options();
    o.inJustDecodeBounds = true;

    BitmapFactory.decodeFile(your_file_path, o);
    o.inJustDecodeBounds = false;
    o.inSampleSize = set_scale_your_need;

    Bitmap bitmap = BitmapFactory.decodeFile(your_file_path, o);
    FileOutputStream fos = new FileOutputStream(your_file_path, false);
    bitmap.compress(Bitmap.CompressFormat.PNG, 90, fos);
    fos.flush();

调整文件内的位图大小而不创建额外的位图/文件？

2 个答案: