WRITE_EXTERNAL_STORAGE不在棒棒糖上工作,即使它已在清单中设置

Question

我正在尝试将应用程序本地数据文件夹中的图像保存到外部存储.我的清单包含以下内容(在清单的应用程序标记之前):

<uses-sdk android:minSdkVersion="14" android:targetSdkVersion="23" />

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" android:maxSdkVersion="18"/>

当我尝试以下

try {
        InputStream in = new FileInputStream(filePath);
        File outPath = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
        File outFile = new File(outPath, "mypicture.jpg");


        //try fails at this line
        OutputStream out = new FileOutputStream(outFile);

        byte[] buf = new byte[1024];
        int len;

        while ((len = in.read(buf)) > 0) {
            out.write(buf, 0, len);
        }

        in.close();
        in = null;
        out.flush();
        out.close();
        out = null;
} catch (IOException e) {
    e.printStackTrace();
}

我收到此错误:

java.io.FileNotFoundException: /storage/emulated/0/Pictures/mypicture.jpg: open failed: EACCES (Permission denied)

我也尝试了一个稍微不同的输出路径:

 String sdCardPath = Environment.getExternalStorageDirectory() + "/MyFolder";
 new File(sdCardPath).mkdirs();
 File outFile = new File(sdCardPath, "mypicture.jpg");

但这也给了我一个错误:

java.io.FileNotFoundException: /storage/emulated/0/MyFolder/mypicture.jpg: open failed: ENOENT (No such file or directory)

该设备运行Android 4.4.2,因此不需要在运行时请求权限(据我所知,它不能请求它们).

为了允许将文件保存到外部存储器,还有其他可能缺少的东西吗？

Answer 1

问题的原因是通过gradle拉入的外部库,它有自己的清单请求 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" android:maxSdkVersion="18">

如果没有包含maxSdkVersion ="18",那么我自己的清单才有效,因此添加该参数的清单合并会导致此错误.我的解决方案是将我自己的清单改为:

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" android:maxSdkVersion="23" tools:replace="android:maxSdkVersion" />

我假设maxSdkVersion ="18"意味着运行SDK 19-22的任何设备都没有此权限(23+能够在运行时请求它).