exposed beyond app through Intent.getData() 下载APK后安装APK

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

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

//判断是否是AndroidN以及更高的版本
        Intent intent = new Intent(Intent.ACTION_VIEW);
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
            Uri contentUri = FileProvider.getUriForFile(mContext, "com.example.administrator.myapplication.fileprovider", file);
            intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
            intent.setDataAndType(contentUri, "application/vnd.android.package-archive");
        } else {
            intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            intent.setDataAndType(Uri.fromFile(file), "application/vnd.android.package-archive");
        }
        mContext.startActivity(intent);
    }