// |==|从位图创建PNG文件:

void devImjFylFnc(String pthAndFylTtlVar, Bitmap iptBmjVar)
{
    try
    {
        FileOutputStream fylBytWrtrVar = new FileOutputStream(pthAndFylTtlVar);
        iptBmjVar.compress(Bitmap.CompressFormat.PNG, 100, fylBytWrtrVar);
        fylBytWrtrVar.close();
    }
    catch (Exception errVar) { errVar.printStackTrace(); }
}

从文件中获取Bimap:

Bitmap getBmjFrmFylFnc(String pthAndFylTtlVar)
{
    return BitmapFactory.decodeFile(pthAndFylTtlVar);
}

嘿，把名字给。bmp

这样做:

ByteArrayOutputStream bytes = new ByteArrayOutputStream();
_bitmapScaled.compress(Bitmap.CompressFormat.PNG, 40, bytes);

//you can create a new file name "test.BMP" in sdcard folder.
File f = new File(Environment.getExternalStorageDirectory()
                        + File.separator + "**test.bmp**")

这将听起来，IM只是愚弄周围，但尝试一下，它会被保存在bmp的foramt..干杯

您应该使用Bitmap.compress()方法将位图保存为文件。它将压缩(如果所使用的格式允许的话)您的图片并将其推入OutputStream。

下面是一个通过getImageBitmap(myurl)获得的位图实例，可以压缩为JPEG，压缩率为85%:

// Assume block needs to be inside a Try/Catch block.
String path = Environment.getExternalStorageDirectory().toString();
OutputStream fOut = null;
Integer counter = 0;
File file = new File(path, "FitnessGirl"+counter+".jpg"); // the File to save , append increasing numeric counter to prevent files from getting overwritten.
fOut = new FileOutputStream(file);

Bitmap pictureBitmap = getImageBitmap(myurl); // obtaining the Bitmap
pictureBitmap.compress(Bitmap.CompressFormat.JPEG, 85, fOut); // saving the Bitmap to a file compressed as a JPEG with 85% compression rate
fOut.flush(); // Not really required
fOut.close(); // do not forget to close the stream

MediaStore.Images.Media.insertImage(getContentResolver(),file.getAbsolutePath(),file.getName(),file.getName());

我知道这个问题很老了，但是现在我们可以在没有WRITE_EXTERNAL_STORAGE权限的情况下实现相同的结果。而不是我们可以使用文件提供程序。

private fun storeBitmap(bitmap: Bitmap, file: File){
        requireContext().getUriForFile(file)?.run {
            requireContext().contentResolver.openOutputStream(this)?.run {
                bitmap.compress(Bitmap.CompressFormat.JPEG, 100, this)
                close()
            }
        }
    }

如何从提供者检索文件?

fun Context.getUriForFile(file: File): Uri? {
        return FileProvider.getUriForFile(
            this,
            "$packageName.fileprovider",
            file
        )
    }

另外，不要忘记在Android manifest中注册你的提供商

<provider
        android:name="androidx.core.content.FileProvider"
        android:authorities="${applicationId}.fileprovider"
        android:exported="false"
        android:grantUriPermissions="true">
        <meta-data
            android:name="android.support.FILE_PROVIDER_PATHS"
            android:resource="@xml/file_paths"/>
    </provider>

保存位图到您的图库没有压缩。

private File saveBitMap(Context context, Bitmap Final_bitmap) {
    File pictureFileDir = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES), "Your Folder Name");
    if (!pictureFileDir.exists()) {
        boolean isDirectoryCreated = pictureFileDir.mkdirs();
        if (!isDirectoryCreated)
            Log.i("TAG", "Can't create directory to save the image");
        return null;
    }
    String filename = pictureFileDir.getPath() + File.separator + System.currentTimeMillis() + ".jpg";
    File pictureFile = new File(filename);
    try {
        pictureFile.createNewFile();
        FileOutputStream oStream = new FileOutputStream(pictureFile);
        Final_bitmap.compress(Bitmap.CompressFormat.PNG, 100, oStream);
        oStream.flush();
        oStream.close();
        Toast.makeText(Full_Screen_Activity.this, "Save Image Successfully..", Toast.LENGTH_SHORT).show();
    } catch (IOException e) {
        e.printStackTrace();
        Log.i("TAG", "There was an issue saving the image.");
    }
    scanGallery(context, pictureFile.getAbsolutePath());
    return pictureFile;
}
private void scanGallery(Context cntx, String path) {
    try {
        MediaScannerConnection.scanFile(cntx, new String[]{path}, null, new MediaScannerConnection.OnScanCompletedListener() {
            public void onScanCompleted(String path, Uri uri) {
                Toast.makeText(Full_Screen_Activity.this, "Save Image Successfully..", Toast.LENGTH_SHORT).show();
            }
        });
    } catch (Exception e) {
        e.printStackTrace();
        Log.i("TAG", "There was an issue scanning gallery.");
    }
}

为什么不调用Bitmap.compress方法100(这听起来像是无损的)?