<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

第一种 AndroidManifest.xml  application节点添加

  android:requestLegacyExternalStorage="true"

<application
    android:name=".app.MyApplication"
    android:allowBackup="false"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:networkSecurityConfig="@xml/network_security_config"
    android:roundIcon="@mipmap/ic_launcher"
    tools:replace="android:allowBackup"
    android:supportsRtl="true"
    android:theme="@style/AppTheme"
    android:requestLegacyExternalStorage="true"//targetSdkVersion >28都需        

第二种，推荐使用 

 Bitmap bitmap = BitmapFactory.decodeResource(getResources(), drawableId);
 String displayName = System.currentTimeMillis() + "jpg";
 String mimeType = "image/jpeg";
 Bitmap.CompressFormat compressFormat = Bitmap.CompressFormat.JPEG;
 DownLoadPictureUtil.addBitmapToAlbum(this,bitmap,displayName,mimeType,compressFormat);

public static void addBitmapToAlbum(Context context,Bitmap bitmap,String displayName ,  String mimeType , Bitmap.CompressFormat compressFormat){
    ContentValues values = new ContentValues();
    values.put(MediaStore.MediaColumns.DISPLAY_NAME, displayName);
    values.put(MediaStore.MediaColumns.MIME_TYPE, mimeType);

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
        values.put(MediaStore.MediaColumns.RELATIVE_PATH, Environment.DIRECTORY_DCIM);
    } else {
        values.put(MediaStore.MediaColumns.DATA, Environment.getExternalStorageDirectory().getPath()+Environment.DIRECTORY_DCIM+displayName);
    }

    ContentResolver contentResolver = context.getContentResolver();
    Uri uri = contentResolver.insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values);


    ToastUtils.show( "保存成功 ");

    if (uri != null) {
        OutputStream outputStream = null;
        try {
            outputStream = contentResolver.openOutputStream(uri);
            bitmap.compress(compressFormat, 100, outputStream);
            outputStream.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        if (outputStream != null) {

        }
    }
}