在AndroidManifest.xml添加provider

file_paths文件：

<?xml version="1.0" encoding="utf-8"?>

    

安装APK

File completeApkfile = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS), aApkName);
if (!completeApkfile.exists()) {
    return;
}
completeApkfile.renameTo(new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS), aApkName.replace(".md", ".apk")));
File apkfile = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS), aApkName.replace(".md", ".apk"));
// 通过Intent安装APK文件
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
Uri apkUri;
// Android 7.0 以上不支持 file://协议 需要通过 FileProvider 访问 sd卡 下面的文件，所以 Uri 需要通过 FileProvider 构造，协议为 content://
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
    // 声明需要的临时权限
    intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
    // content:// 协议
    apkUri = FileProvider.getUriForFile(mContext.getApplicationContext(), "包名.fileProvider", apkfile);
} else {
    // file:// 协议
    apkUri = Uri.fromFile(apkfile);
}
intent.setDataAndType(apkUri, "application/vnd.android.package-archive");
aContext.startActivity(intent);