Glide下载图片并保存到本地

      Observable.create(new ObservableOnSubscribe() {
        @Override
        public void subscribe(ObservableEmitter e) throws Exception {
            //通过gilde下载得到file文件,这里需要注意android.permission.INTERNET权限
            e.onNext(Glide.with(mContext)
                    .load(imagePathList.get(currentViewPosition).getPath())
                    .downloadOnly(Target.SIZE_ORIGINAL, Target.SIZE_ORIGINAL)
                    .get());
            e.onComplete();
        }
    }).subscribeOn(Schedulers.io())
            .observeOn(Schedulers.newThread())
            .subscribe(new Consumer() {
        @Override
        public void accept(File file) throws Exception {
            //获取到下载得到的图片，进行本地保存
            File pictureFolder = Environment.getExternalStorageDirectory();
            //第二个参数为你想要保存的目录名称
            File appDir = new File(pictureFolder, "your_picture_save_path");
            if (!appDir.exists()) {
                appDir.mkdirs();
            }
            String fileName = System.currentTimeMillis() + ".jpg";
            File destFile = new File(appDir, fileName);
            //把gilde下载得到图片复制到定义好的目录中去
            copy(file, destFile);

            // 最后通知图库更新
            sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE,
                    Uri.fromFile(new File(destFile.getPath()))));
        }
    });

带上复制文件的方法：

 /**
     * 复制文件
     *
     * @param source 输入文件
     * @param target 输出文件
     */
    public void copy(File source, File target) {
        FileInputStream fileInputStream = null;
        FileOutputStream fileOutputStream = null;
        try {
            fileInputStream = new FileInputStream(source);
            fileOutputStream = new FileOutputStream(target);
            byte[] buffer = new byte[1024];
            while (fileInputStream.read(buffer) > 0) {
                fileOutputStream.write(buffer);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                fileInputStream.close();
                fileOutputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

最后需要注意的下载保存需要读写权限，6.0以后需手动申请权限
android.permission.WRITE_EXTERNAL_STORAGE
android.permission.READ_EXTERNAL_STORAGE