Extending RelativeLayout by inflating from xml?

今天需要写一个简答的自定义view，需要在relativelayout里添加几个textview。

按说很简单的需求，折腾半天还是不行。后来直接google+stackoverflow，终于在这里找到了答案。

Extending RelativeLayout by inflating from xml?

问题：

I want to create a class named TabView which extends RelativeLayout and it is inflated from xml that contains RelativeLayout. The thing is that it doesn't seem to work as I expected. Did I do something wrong in the constructor? I know layoutInflater.inflate returns View object but what do I have to make it equal to? Any advice is apprecited!

我想创建一个类名为TabView的ViewGroup，它扩展自RelativeLayout。它是有包含RelativeLayout的xmf填充的。问题是它看起来不像我想的那样工作。我在构造函数里做了什么误操作么？我知道layoutinflater.inflate返回View对象，但是我应该怎么做呢？任何建议都可以

private class TabView extends RelativeLayout {
    private int mIndex;

    public TabView(Context context) {
        super(context, null, R.attr.vpiTabPageIndicatorStyle);
        LayoutInflater layoutInflater = LayoutInflater.from(context);
        layoutInflater.inflate(R.layout.tabview_title_subtitle, null);
    }

    public int getIndex() {
        return mIndex;
    }

    public void setTitle() {
        TextView title = (TextView)findViewById(R.id.title);
        title.setText("Followers");
    }

    public void setSubitle() {
        TextView subtitle = (TextView)findViewById(R.id.subtitle);
        subtitle.setText("435");
    }
}

The following is tabview_title_subtitle.xml

以下是tabview_title_subtitle.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <TextView
        android:id="@+id/title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:text="Title"
        android:textAppearance="?android:attr/textAppearanceMedium" />

    <TextView
        android:id="@+id/subtitle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_below="@+id/title"
        android:text="Subtitle"
        android:textAppearance="?android:attr/textAppearanceMedium" />

</RelativeLayout>

答案：

First, your layout should look like this:

首先，你的布局应该长这样：

<?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >

<TextView
    android:id="@+id/title"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:text="Title"
    android:textAppearance="?android:attr/textAppearanceMedium" />

<TextView
    android:id="@+id/subtitle"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_below="@+id/title"
    android:text="Subtitle"
    android:textAppearance="?android:attr/textAppearanceMedium" />

</merge>

In other way you'll end up with RelativeLayout that contains another RelativeLayout

你不应当在一个RelativeLayout里包含另一个RelativeLayout。
Second. Inflate it like this:

第二，填充操作应该长这样：

layoutInflater.inflate(R.layout.tabview_title_subtitle, this);    

在第一步写xml和java文件时，也可以使用RelateLayout，然后类文件中，extends FrameLayout，也可以达到想要的效果。