Manually inflating custom view yields different layouts for ActionBar custom view

问题

Custom view from resource:

// Set up the action bar.
final ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
actionBar.setCustomView(R.layout.custom_action_bar);
actionBar.setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM);

the result is:

Custom view manually inflated:

// Set up the action bar.
final ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
LayoutInflater inflater = (LayoutInflater) this .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View view = inflater.inflate(R.layout.custom_action_bar, null);
actionBar.setCustomView(view);
actionBar.setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM);

the result is:

custom_action_bar.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal" 
    android:weightSum="3">

    <TextView 
        android:id="@+id/bar_title1"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:textColor="@color/White"
        android:text="title1"/>
    <TextView 
        android:id="@+id/bar_title2"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:textColor="@color/White"
        android:text="title2"/>
    <TextView 
        android:id="@+id/bar_title3"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:textColor="@color/White"
        android:text="title3"/>

</LinearLayout>

The first layout shown here is the correct one, because it has weights on its widgets. The second attempt should produce the same result, but it does not.

回答1:

Actually, the issue here is that in second case ActionBar needs additonal layout parameters:

    final ActionBar actionBar = getActionBar();
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
    LayoutInflater inflater = (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    View view = inflater.inflate(R.layout.custom_action_bar, null);
    actionBar.setCustomView(view, new ActionBar.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
    actionBar.setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM);

So, it covers all ActionBar area. Looks like by default WRAP_CONTENT llayout parameters get applied to custom view.

回答2:

Another options is to let the ActionBar do the work for you (in this case I'm showing how to do it with the support version).

// Set your custom view
getSupportActionBar().setCustomView(R.layout.custom_action_bar);

// Get the inflated view
View view = getSupportActionBar().getCustomView();

// Do what you want with the view (set the title, custom font etc.)
TextView actionBarTitle = (TextView) view.findViewById(R.id.action_bar_title);
...

// set the custom flag
getSupportActionBar().setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM)

来源：https://stackoverflow.com/questions/17521745/manually-inflating-custom-view-yields-different-layouts-for-actionbar-custom-vie