为视频创建一个视频缩略图。如果视频损坏或格式不支持，它可能返回null。

private void makeVideoPreview() {
    Bitmap thumbnail = ThumbnailUtils.createVideoThumbnail(videoAbsolutePath, MediaStore.Images.Thumbnails.MINI_KIND);
    saveImage(thumbnail);
}

使用以下代码将位图保存在sdcard中

商店形象

private void storeImage(Bitmap image) {
    File pictureFile = getOutputMediaFile();
    if (pictureFile == null) {
        Log.d(TAG,
                "Error creating media file, check storage permissions: ");// e.getMessage());
        return;
    } 
    try {
        FileOutputStream fos = new FileOutputStream(pictureFile);
        image.compress(Bitmap.CompressFormat.PNG, 90, fos);
        fos.close();
    } catch (FileNotFoundException e) {
        Log.d(TAG, "File not found: " + e.getMessage());
    } catch (IOException e) {
        Log.d(TAG, "Error accessing file: " + e.getMessage());
    }  
}

获取图像存储路径

/** Create a File for saving an image or video */
private  File getOutputMediaFile(){
    // To be safe, you should check that the SDCard is mounted
    // using Environment.getExternalStorageState() before doing this. 
    File mediaStorageDir = new File(Environment.getExternalStorageDirectory()
            + "/Android/data/"
            + getApplicationContext().getPackageName()
            + "/Files"); 

    // This location works best if you want the created images to be shared
    // between applications and persist after your app has been uninstalled.

    // Create the storage directory if it does not exist
    if (! mediaStorageDir.exists()){
        if (! mediaStorageDir.mkdirs()){
            return null;
        }
    } 
    // Create a media file name
    String timeStamp = new SimpleDateFormat("ddMMyyyy_HHmm").format(new Date());
    File mediaFile;
        String mImageName="MI_"+ timeStamp +".jpg";
        mediaFile = new File(mediaStorageDir.getPath() + File.separator + mImageName);  
    return mediaFile;
} 

为视频创建一个视频缩略图。如果视频损坏或格式不支持，它可能返回null。

private void makeVideoPreview() {
    Bitmap thumbnail = ThumbnailUtils.createVideoThumbnail(videoAbsolutePath, MediaStore.Images.Thumbnails.MINI_KIND);
    saveImage(thumbnail);
}

使用以下代码将位图保存在sdcard中

商店形象

private void storeImage(Bitmap image) {
    File pictureFile = getOutputMediaFile();
    if (pictureFile == null) {
        Log.d(TAG,
                "Error creating media file, check storage permissions: ");// e.getMessage());
        return;
    } 
    try {
        FileOutputStream fos = new FileOutputStream(pictureFile);
        image.compress(Bitmap.CompressFormat.PNG, 90, fos);
        fos.close();
    } catch (FileNotFoundException e) {
        Log.d(TAG, "File not found: " + e.getMessage());
    } catch (IOException e) {
        Log.d(TAG, "Error accessing file: " + e.getMessage());
    }  
}

获取图像存储路径

/** Create a File for saving an image or video */
private  File getOutputMediaFile(){
    // To be safe, you should check that the SDCard is mounted
    // using Environment.getExternalStorageState() before doing this. 
    File mediaStorageDir = new File(Environment.getExternalStorageDirectory()
            + "/Android/data/"
            + getApplicationContext().getPackageName()
            + "/Files"); 

    // This location works best if you want the created images to be shared
    // between applications and persist after your app has been uninstalled.

    // Create the storage directory if it does not exist
    if (! mediaStorageDir.exists()){
        if (! mediaStorageDir.mkdirs()){
            return null;
        }
    } 
    // Create a media file name
    String timeStamp = new SimpleDateFormat("ddMMyyyy_HHmm").format(new Date());
    File mediaFile;
        String mImageName="MI_"+ timeStamp +".jpg";
        mediaFile = new File(mediaStorageDir.getPath() + File.separator + mImageName);  
    return mediaFile;
} 

try (FileOutputStream out = new FileOutputStream(filename)) {
    bmp.compress(Bitmap.CompressFormat.PNG, 100, out); // bmp is your Bitmap instance
    // PNG is a lossless format, the compression factor (100) is ignored
} catch (IOException e) {
    e.printStackTrace();
}

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.");
    }
}

在onActivityResult:

String filename = "pippo.png";
File sd = Environment.getExternalStorageDirectory();
File dest = new File(sd, filename);

Bitmap bitmap = (Bitmap)data.getExtras().get("data");
try {
     FileOutputStream out = new FileOutputStream(dest);
     bitmap.compress(Bitmap.CompressFormat.PNG, 90, out);
     out.flush();
     out.close();
} catch (Exception e) {
     e.printStackTrace();
}

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>