FileProvider崩溃 - 尝试在空字符串上调用XmlResourceParser

Question

这是我的清单的一部分:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.asd"
    android:versionCode="118"
    android:versionName="118" >

    <uses-sdk
        android:minSdkVersion="14"
        android:targetSdkVersion="19" />


    <application
        android:name="com.example.asd.AsdApplication"
        android:allowBackup="true"
        android:allowTaskReparenting="true"
        android:theme="@style/AsdTheme" >
        ...

        <provider
            android:name="com.example.asd.database.hq.ContentProviderDB"
            android:authorities="ourContentProviderAuthorities" >
        </provider>
        <provider
            android:name="android.support.v4.content.FileProvider"
            android:authorities="com.example.asd.fileprovider"
            android:exported="false"
            android:grantUriPermissions="true">
            <meta-data
                android:name="android.support.FILE_PROVIDER_PATHS"
                android:resource="@xml/filepaths" />
        </provider>

       ...
    </application>

</manifest>

这是raw/xml/filepaths.xml中的filepaths文件

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <files-path name="media"/>
</paths>

我从互联网下载视频并以这种方式将其保存到内部存储:

public static boolean saveInputStreamToInternalStorageFile(Context context, String filename, byte[] dataToWrite, Context ctx) {
    FileOutputStream fos;
    try {
        fos = new FileOutputStream(context.getFilesDir() + File.separator + filename);

        ObjectOutputStream oos = new ObjectOutputStream(fos);
        oos.writeObject(dataToWrite);
        oos.close();
        return true;
    } catch (FileNotFoundException e) {
        e.printStackTrace();
        return false;
    } catch (IOException e) {
        e.printStackTrace();
        return false;
    }
}

我试着像这样使用它:

private void playVideoFromDeviceWithWorkaround(String fileName) {

    File newFile = new File(getFilesDir(), fileName);
    Uri contentUri = FileProvider.getUriForFile(getApplicationContext(), "com.example.asd", newFile);

    try {
        vvVideoFullscreen.setVideoURI(contentUri);
        showMediaControls = true;
        playVideo();
    } catch (Exception e) {
        playVideoFromNetwork();
    }

}

在这一行:

Uri contentUri = FileProvider.getUriForFile(getApplicationContext(), "com.example.asd", newFile); 

我收到以下错误:

java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.res.XmlResourceParser android.content.pm.ProviderInfo.loadXmlMetaData(android.content.pm.PackageManager, java.lang.String)' on a null object reference
at android.support.v4.content.FileProvider.parsePathStrategy(FileProvider.java:560)
at android.support.v4.content.FileProvider.getPathStrategy(FileProvider.java:534)
at android.support.v4.content.FileProvider.getUriForFile(FileProvider.java:376)

Answer 1

问题是在Manifest中我有这条线:

android:authorities="com.example.asd.fileprovider"

当我调用getUriForFile时,我正在传递:

Uri contentUri = FileProvider.getUriForFile(getApplicationContext(), "com.example.asd", newFile); 

所以改变"com.example.asd"了"com.example.asd.fileprovider",它起作用了

Answer 2

你可以做到这一点没有用的能够运行在同一台设备(想想在多个变种一个额外的好处硬编码的包名release和debug用applicationIdSuffix,看到这些问题):

基于 FileProvider.java:560

final ProviderInfo info = context.getPackageManager()
        .resolveContentProvider(authority, PackageManager.GET_META_DATA);
final XmlResourceParser in = info.loadXmlMetaData( //560
        context.getPackageManager(), META_DATA_FILE_PROVIDER_PATHS);

你使用了错误authority而且没有找到ContentProvider(info == null).

${applicationId}将您的清单更改为(将由Manifest Merger取代)

android:authorities="${applicationId}.share"

和

Uri uri = FileProvider.getUriForFile(context, context.getPackageName() + ".share", result);

该.share后缀是可选的,如果你有一个真正的ContentProvider这是更好地为有权威的包名.

Answer 3

在我的情况下,我得到了错误,因为

BuildConfig.APPLICATION_ID

正在从中进口

import android.support.v4.BuildConfig;

所以它返回的字符串"android.support.v4"不是我的项目包名.检查导入文件来自您import project.Buildconfig而非另一个.例:

import com.example.yourProjectName.BuildConfig;

最后,在<provider>Manifest 中的标签中,我必须android:authorities="${applicationId}"始终将项目包名称作为权限

<manifest>
   ..
   ..
   <application>
    ..
    ..
       <provider
            android:name="android.support.v4.content.FileProvider"
            android:authorities="${applicationId}"
            android:exported="false"
            android:grantUriPermissions="true">
            <meta-data
                android:name="android.support.FILE_PROVIDER_PATHS"
                android:resource="@xml/ruta_fileprovider" />
        </provider>

    </application>

</manifest>

Answer 4

首先，请确保您的提供程序android:authorities与其他提供程序不冲突。除此之外，您可以为名称的最后一部分选择任何名称：“ provider”，“ fileprovider”等，但是当android:authorities列出多个列表时，应用程序崩溃，而文档指出它允许列出多个值。

file://现在，不允许在targetSdkVersion> = 24（Android N 7.0）上使用Intent附加方案，仅对content://所有设备（Android 5、6和7）传递该方案。但是我们遇到了小米违反此Google约定并发送file://，因此data.getData().getAuthority()给出了空字符串。

final String uriScheme = currentUri.getScheme();
if ("content".equals(uriScheme)) {
    // getting full file path (works with some providers, i.e. Gallery)
    path = FileUtils.getPath(getContext(), currentUri);
    if (path != null) {
         currentFile = new File(path);
    }
} else if ("file".equals(uriScheme)) {
    // in a rare case we received file:// in currentUri, we need to:
    // 1. create new File variable from currentUri that looks like "file:///storage/emulated/0/download/50044382b.jpg"
    // 2. generate a proper content:// Uri for it
    currentFile = new File(currentUri.getPath());
    String authority = data.getData().getAuthority();
    if (authority != null && !authority.isEmpty()) {
        currentUri = FileProvider.getUriForFile(getActivity(), authority, currentFile);
    }
} else {
    // throw exception
}

另外，FileProvider.getUriForFile()导致崩溃的错误java.lang.IllegalArgumentException: Failed to find configured root that contains /storage/emulated/0/Android/data/com.example/files/attachments/image.jpg已在Android支持库v24.2.0中修复。问题是FileProvider.java没有看到外部路径文件夹。