如何在XML输出中缩进元素属性？

Question

我正在开发一个在我的Manifest.xml文件末尾插入一个活动的程序。

所以我解析XML，将活动添加到应用程序节点并对其进行转换。 问题是，当有超过1个属性时，我会丢失每个换行符的XML文件格式。

这是我想要的XML文件。

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.agocean.symphyweb.presentation">

    <uses-permission android:name="android.permission.READ_PHONE_STATE" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.CALL_PHONE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

    <uses-feature
        android:name="android.hardware.camera"
        android:required="true" />

    <application
        android:name=".AndroidApplication"
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity
            android:name=".ui.activities.MainActivity"
            android:label="@string/app_name"
            android:theme="@style/AppTheme">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".ui.activities.LoginActivity" />
        <activity android:name=".ui.activities.OtherActivity"/>
    </application>

这就是我得到的：

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.agocean.symphyweb.presentation">

    <uses-permission android:name="android.permission.READ_PHONE_STATE"/>
    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
    <uses-permission android:name="android.permission.CALL_PHONE"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>

    <uses-feature android:name="android.hardware.camera" android:required="true"/>

    <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:name=".AndroidApplication" android:supportsRtl="true" android:theme="@style/AppTheme">
        <activity android:label="@string/app_name" android:name=".ui.activities.MainActivity" android:theme="@style/AppTheme">
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>

                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
        <activity android:name=".ui.activities.LoginActivity"/>
    <activity android:name=".ui.activities.OtherActivity"/>
    </application>

</manifest>

我甚至不知道为什么最后一个活动元素没有正确缩进

以下是我使用的代码：

DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
domFactory.setIgnoringComments(true);
DocumentBuilder builder = domFactory.newDocumentBuilder();
File f = new File(MANIFEST);
Document doc = builder.parse(f);

NodeList nodes = doc.getElementsByTagName("application");
System.out.println(nodes.getLength());
Element activity = doc.createElement("activity");
activity.setAttribute("android:name", ".ui.activities." + prefixClass + "Activity");
nodes.item(0).appendChild(activity);

Transformer tf = TransformerFactory.newInstance().newTransformer();
tf.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
tf.setOutputProperty(OutputKeys.INDENT, "yes");
tf.setOutputProperty(OutputKeys.STANDALONE, "yes");
tf.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "4");

DOMSource domSource = new DOMSource(doc);
StreamResult sr = new StreamResult(new File(MANIFEST));
tf.transform(domSource, sr);