以前打本本地文件方式

Intent intent = new Intent();
File file = new File(filePath);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.setAction(Intent.ACTION_VIEW);  //设置intent的Action属性
String type = getMIMEType(file );  //获取文件file的MIME类型
intent.setDataAndType(Uri.fromFile(file , type));   //设置intent的data和Type属性。
startActivity(intent);

记得以前是这样通过本地程序打开一个本地文件，程序会根据文件类型提示用户选择一个程序打开对应的文件，现在在Android7以上设备上这样写时会出现错误，应该是系统出于安全考虑不让这样简单的就打开本地文件

android.os.FileUriExposedException XXX exposed beyond app through Intent.get

现在想要打开文件，需要做一个额外的事情

在res中创建一个xml文件夹，里面创建一个配置文件

2021-12-13_173309.png

这个文件的名称可以自定义，配置文件的内容也比较简单

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

在AndroidManifest文件的application节点中声明这个provider

<application
    android:name="org.venus.library.app.LibraryApplication"
    android:allowBackup="true"
    android:icon="@drawable/icon_app"
    android:label="@string/app_name"
    android:roundIcon="@drawable/icon_app"
    android:supportsRtl="true"
    android:theme="@style/NoTitleBar">

    <activity android:name=".ui.activity.LoginActivity" android:screenOrientation="userLandscape" android:windowSoftInputMode="stateHidden">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

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

provider>meta-data>android:resource指向上文中创建的配置文件

使用时将以前的Uri对象创建方式Uri uri1 = Uri.fromFile(file);改成Uri uri = FileProvider.getUriForFile(this, getApplicationContext().getPackageName() + ".provider", file);

将打开本地文件的代码写成一个工具类

package org.venus.mpfd.ui.fragment;

import android.content.Context;
import android.content.Intent;
import android.net.Uri;

import androidx.core.content.FileProvider;

import java.io.File;

/**
 * Author      Jxx          _让世界看到我
 * On          2021/12/13
 * Note        TODO
 */
public class FileUtil {

    /**
     * 打开本地文件
     *
     * @param context
     * @param filePath
     */
    public static void openFile(Context context, String filePath) {
        Intent intent = new Intent();
        File file = new File(filePath);
        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        intent.setAction(Intent.ACTION_VIEW);
        Uri uri = FileProvider.getUriForFile(context, context.getApplicationContext().getPackageName() + ".provider", file);
        intent.setDataAndType(uri, getMIMEType(file));
        context.startActivity(intent);
    }

    /**
     * 获取文件mime类型
     *
     * @param file
     * @return
     */
    private static String getMIMEType(File file) {
        String type = "*/*";
        String fName = file.getName();
        //获取后缀名前的分隔符"."在fName中的位置。
        int dotIndex = fName.lastIndexOf(".");
        if (dotIndex < 0) {
            return type;
        }
        /* 获取文件的后缀名 */
        String fileType = fName.substring(dotIndex, fName.length()).toLowerCase();
        if (fileType == null || "".equals(fileType)) {
            return type;
        }
        //在MIME和文件类型的匹配表中找到对应的MIME类型。
        for (int i = 0; i < MIME_MapTable.length; i++) {
            if (fileType.equals(MIME_MapTable[i][0]))
                type = MIME_MapTable[i][1];
        }
        return type;
    }

    /**
     * 文件mime类型
     */
    private static final String[][] MIME_MapTable = {
            {".3gp", "video/3gpp"},
            {".apk", "application/vnd.android.package-archive"},
            {".asf", "video/x-ms-asf"},
            {".avi", "video/x-msvideo"},
            {".bin", "application/octet-stream"},
            {".bmp", "image/bmp"},
            {".c", "text/plain"},
            {".class", "application/octet-stream"},
            {".conf", "text/plain"},
            {".cpp", "text/plain"},
            {".doc", "application/msword"},
            {".exe", "application/octet-stream"},
            {".gif", "image/gif"},
            {".gtar", "application/x-gtar"},
            {".gz", "application/x-gzip"},
            {".h", "text/plain"},
            {".htm", "text/html"},
            {".html", "text/html"},
            {".jar", "application/java-archive"},
            {".java", "text/plain"},
            {".jpeg", "image/jpeg"},
            {".jpg", "image/jpeg"},
            {".js", "application/x-javascript"},
            {".log", "text/plain"},
            {".m3u", "audio/x-mpegurl"},
            {".m4a", "audio/mp4a-latm"},
            {".m4b", "audio/mp4a-latm"},
            {".m4p", "audio/mp4a-latm"},
            {".m4u", "video/vnd.mpegurl"},
            {".m4v", "video/x-m4v"},
            {".mov", "video/quicktime"},
            {".mp2", "audio/x-mpeg"},
            {".mp3", "audio/x-mpeg"},
            {".mp4", "video/mp4"},
            {".mpc", "application/vnd.mpohun.certificate"},
            {".mpe", "video/mpeg"},
            {".mpeg", "video/mpeg"},
            {".mpg", "video/mpeg"},
            {".mpg4", "video/mp4"},
            {".mpga", "audio/mpeg"},
            {".msg", "application/vnd.ms-outlook"},
            {".ogg", "audio/ogg"},
            {".pdf", "application/pdf"},
            {".png", "image/png"},
            {".pps", "application/vnd.ms-powerpoint"},
            {".ppt", "application/vnd.ms-powerpoint"},
            {".prop", "text/plain"},
            {".rar", "application/x-rar-compressed"},
            {".rc", "text/plain"},
            {".rmvb", "audio/x-pn-realaudio"},
            {".rtf", "application/rtf"},
            {".sh", "text/plain"},
            {".tar", "application/x-tar"},
            {".tgz", "application/x-compressed"},
            {".txt", "text/plain"},
            {".wav", "audio/x-wav"},
            {".wma", "audio/x-ms-wma"},
            {".wmv", "audio/x-ms-wmv"},
            {".wps", "application/vnd.ms-works"},
            //{".xml",    "text/xml"},
            {".xml", "text/plain"},
            {".z", "application/x-compress"},
            {".zip", "application/zip"},
            {"", "*/*"}
    };
}