设置XML的自定义视图的标签缩写

Question

In my app I extend LinearLayout and RelativeLayout , so every time I need to declare a layout in XML (which you may know it's quite often) I need to write a long tag , in order to point to the view's package.

So the XML files look like this:

<com.company.material.widget.LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <com.company.material.widget.RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="@dimen/titlebar_height"
        android:background="@color/primary"
        android:orientation="horizontal">

        <TextView
            style="@style/Text.Field.Small"
            android:id="@+id/form_title"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"/>

        <Button
            style="@style/Button.Main"
            android:id="@+id/form_submit"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"/>
    </com.company.material.widget.RelativeLayout>

    <com.company.essentials.view.FormView
        android:id="@+id/formview"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
...

This is chaotic!

Is there any way to abbreviate this? Like AppLinearLayout instead of com.company.material.widget.LinearLayout ?

Thanks in advance!

Answer 1

If it's worth it to you, you can customize your activity's layout inflater.

public class MyActivity extends Activity implements LayoutInflater.Factory {
    @Override public void onCreate(Bundle _icicle) {
        super.onCreate(_icicle);
        setContentView(R.layout.my_activity);
    }

    @Override public Object getSystemService(String _name) {
        Object service = super.getSystemService(_name);
        if(LAYOUT_INFLATER_SERVICE.equals(_name)) {
            LayoutInflater myInflater = ((LayoutInflater)service).cloneInContext(this);
            myInflater.setFactory(this);
            return myInflater;
        }
        return service;
    }

    @Override public View onCreateView (String _tag, Context _ctx, AttributeSet _as) {
        if("mytag".equals(_tag))
            return new MyLinearLayout(_ctx, _as);
        else
            return null;
    }
}

setContentView will call getSystemService to obtain a layout inflater, and for each tag that layout inflater will query each of its factories (including our custom one) to see if the factory knows how to create the object that corresponds to that tag.

Answer 2

You could move your View class to the android.view package. This would allow you to just write <AppRelativeLayout /> instead of <com.company.material.widget.AppRelativeLayout /> , since View tag names without package prefixes are 'auto-completed' to the android.view package.

If you don't want to move your whole class to this package, you may just create a dummy sub-class à la:

package android.view;

public class AppRelativeLayout extends com.company.material.widget.RelativeLayout {
    // same constructors as super class
    public AppRelativeLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
    }
}

You just have to make sure you don't use the same class names as the Android framework already does, such as RelativeLayout , since that would clash with the existing views and layout names. That's why I named the example above AppRelativeLayout .

Answer 3

There is alternative option as well if you like you can do it like this

<view
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    class="com.company.material.widget.LinearLayout" 
    android:orientation="vertical">