Android 7.0 FileProvider踩过的坑

前言：下面记录两个在7.0系统之后使用FileProvider遇到的问题

问题一：

Error:C:***AndroidManifest.xml:352:13-62 Error:
	Attribute provider#android.support.v4.content.FileProvider@authorities value=(***.fileProvider) from AndroidManifest.xml:352:13-62
	is also present at [com.jph.takephoto:takephoto_library:4.0.3] AndroidManifest.xml:19:13-64 value=(***.fileprovider).
	Suggestion: add 'tools:replace="android:authorities"' to  element at AndroidManifest.xml:350:9-358:20 to override.
FAILURE: Build failed with an exception.

清单文件配置如下：

这个问题上面的报错信息里其实已经说的很明确了，反复添加

android:authorities="***.fileProvider"

出现的原因是因为我的项目添加了一个第三方的库，而第三方库的清单文件里也添加了这段代码，导致了冲突。

解决方法在错误日志中也给出了：在我们自己的清单文件中添加下面代码：

xmlns:tools="http://schemas.android.com/tools"
tools:replace="android:authorities"

添加后的代码如下：

重新编译通过。

问题二：

          清单文件里对FileProvider的注册和问题一修复后的代码一致。

         代码中的使用如下：

         Uri uri = FileProvider.getUriForFile( this, "***.filerovider", mTempFile);

每次运行到这段代码的时候都会报错，导致app崩溃：

Caused by: 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:583)
                                                                  at android.support.v4.content.FileProvider.getPathStrategy(FileProvider.java:557)
                                                                  at android.support.v4.content.FileProvider.getUriForFile(FileProvider.java:399)

进入FileProvider.getUriForFile();查看一个源码：

/**
 * Return a content URI for a given {@link File}. Specific temporary
 * permissions for the content URI can be set with
 * {@link Context#grantUriPermission(String, Uri, int)}, or added
 * to an {@link Intent} by calling {@link Intent#setData(Uri) setData()} and then
 * {@link Intent#setFlags(int) setFlags()}; in both cases, the applicable flags are
 * {@link Intent#FLAG_GRANT_READ_URI_PERMISSION} and
 * {@link Intent#FLAG_GRANT_WRITE_URI_PERMISSION}. A FileProvider can only return a
 * content {@link Uri} for file paths defined in their <paths>
 * meta-data element. See the Class Overview for more information.
 *
 * @param context A {@link Context} for the current component.
 * @param authority The authority of a {@link FileProvider} defined in a
 *            {@code } element in your app's manifest.
 * @param file A {@link File} pointing to the filename for which you want a
 * content {@link Uri}.
 * @return A content URI for the file.
 * @throws IllegalArgumentException When the given {@link File} is outside
 * the paths supported by the provider.
 */
public static Uri getUriForFile(Context context, String authority, File file) {
    final PathStrategy strategy = getPathStrategy(context, authority);
    return strategy.getUriForFile(file);
}

主要看一下对第二个参数的介绍，大致意思是说：这里的参数需要和清单文件里的

android:authorities="***.fileProvider"

 保持一致。好吧，问题就是出在这里，authorities要一模一样，包括大小写。