我试图用相机拍照,但我得到以下错误:

FATAL EXCEPTION: main
Process: com.example.marek.myapplication, PID: 6747
java.lang.IllegalArgumentException: Failed to find configured root that contains /storage/emulated/0/Android/data/com.example.marek.myapplication/files/Pictures/JPEG_20170228_175633_470124220.jpg
    at android.support.v4.content.FileProvider$SimplePathStrategy.getUriForFile(FileProvider.java:711)
    at android.support.v4.content.FileProvider.getUriForFile(FileProvider.java:400)
    at com.example.marek.myapplication.MainActivity.dispatchTakePictureIntent(MainActivity.java:56)
    at com.example.marek.myapplication.MainActivity.access$100(MainActivity.java:22)
    at com.example.marek.myapplication.MainActivity$1.onClick(MainActivity.java:35)

AndroidManifest.xml:

<provider
        android:name="android.support.v4.content.FileProvider"
        android:authorities="com.example.marek.myapplication.fileprovider"
        android:enabled="true"
        android:grantUriPermissions="true">
        <meta-data
            android:name="android.support.FILE_PROVIDER_PATHS"
            android:resource="@xml/file_paths" />
</provider>

Java:

Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    // Ensure that there's a camera activity to handle the intent
    if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
        // Create the File where the photo should go
        File photoFile = null;
        try {
            photoFile = createImageFile();
        } catch (IOException ex) {
            Toast.makeText(getApplicationContext(), "Error while saving picture.", Toast.LENGTH_LONG).show();
        }
        // Continue only if the File was successfully created
        if (photoFile != null) {
            Uri photoURI = FileProvider.getUriForFile(this,
                    "com.example.marek.myapplication.fileprovider",
                    photoFile);
            takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoURI);
            startActivityForResult(takePictureIntent, REQUEST_TAKE_PHOTO);
        }
    }

file_paths.xml

<?xml version="1.0" encoding="utf-8"?>
<paths>
    <files-path name="my_images" path="images/"/>
</paths>

我一整天都在搜索这个错误,试图理解FileProvider,但我不知道这个错误消息试图告诉我什么。如果你想要更多信息/代码,请在评论中告诉我。


当前回答

来自@CommonsWare的答案很棒。

但在我的例子中,我必须添加多条路径。

<?xml version="1.0" encoding="utf-8"?>
<paths>
    <external-path name="external_files" path="." />
    <files-path name="external_files" path="." />
</paths>

其他回答

xml file_paths文件中的以下更改对我有用。

 <external-files-path name="my_images" path="Pictures"/>
 <external-files-path name="my_movies" path="Movies"/>

您的文件存储在getExternalFilesDir()下。它映射到<external-files-path>,而不是<files-path>。此外,您的文件路径中不包含图像/,因此XML中的path属性无效。

将res/xml/file_paths.xml替换为:

<?xml version="1.0" encoding="utf-8"?>
<paths>
    <external-files-path name="my_images" path="/" />
</paths>

更新 2020 3月 13

特定路径的提供者路径如下:

<files-path/>——> <cache-path/>——> <external-path/>——> Environment.getExternalStorageDirectory() <external-files-path/>——> Context.getExternalFilesDir(String) <external-cache-path/>——> Context.getExternalCacheDir() <external-media-path/>——> Context.getExternalMediaDirs()

裁判:https://developer.android.com/reference/androidx/core/content/FileProvider

问题可能不仅仅是路径xml。

以下是我的解决方案:

查看android.support.v4.content.FileProvider$SimplePathStrategy.getUriForFile()中的根课程:

    public File getFileForUri(Uri uri) {
        String path = uri.getEncodedPath();

        final int splitIndex = path.indexOf('/', 1);
        final String tag = Uri.decode(path.substring(1, splitIndex));
        path = Uri.decode(path.substring(splitIndex + 1));

        final File root = mRoots.get(tag); // mRoots is parsed from path xml
        if (root == null) {
            throw new IllegalArgumentException("Unable to find configured root for " + uri);
        }

        // ...
    }

这意味着mRoots应该包含所请求uri的标记。所以我写了一些代码来打印mRoots和uri的标签,然后很容易发现标签不匹配。

结果是将提供者权限设置为${applicationID}。提供者是个愚蠢的想法!这个权限非常常见,可能会被其他提供者使用,这会弄乱路径配置!

如果没有任何帮助,你会得到错误

failed to find configured root that contains /data/data/...

然后试着改变一些线,比如:

File directory = thisActivity.getDir("images", Context.MODE_PRIVATE);

to:

File directory = new File(thisActivity.getFilesDir(), "images");

在XML文件中:

<files-path name="files" path="." />

这很奇怪,因为我访问的文件夹是/images。

我确信我是迟到了,但以下几点对我很有用。

<paths>
    <root-path name="root" path="." />
</paths>