Where do I define XML for the Toolbar widget in An

问题:

Okay, I've been going through several StackOverflow posts now, but I'm still confused as to where this xml for my Toolbar goes.

<android.support.v7.widget.Toolbar
android:id=”@+id/my_awesome_toolbar”
android:layout_height=”wrap_content”
android:layout_width=”match_parent”
android:background=”@styles/colorPrimary” />

Does it go in my /layout/activity_main.xml?

回答1:

Toolbar is a generalization of Action bars for use within app layouts, now to answer your question there are two practices:

Bad practice:

Bad practice is to define the Toolbar in every layouts.

Standard practice:

Standard practice is to define a layout and reference it in a base activity. You just need to include this Toolbar layout in whichever layout you want (by using <include>) and extend the defined base activity in whichever activity.

This standard practice will help you keeping a single code base for Toolbar and save your time from defining Toolbar every time.

Example: Google I/O 2014 android app

toolbar_actionbar_with_headerbar.xml

<android.support.v7.widget.Toolbar xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:iosched="http://schemas.android.com/apk/res-auto"
    style="@style/HeaderBar"
    iosched:theme="@style/ActionBarThemeOverlay"
    iosched:popupTheme="@style/ActionBarPopupThemeOverlay"
    android:id="@+id/toolbar_actionbar"
    iosched:titleTextAppearance="@style/ActionBar.TitleText"
    iosched:contentInsetStart="?actionBarInsetStart"
    android:layout_width="match_parent"
    android:layout_height="?actionBarSize" />

This toolbar layout is referenced in settings activity as given below:

activity_settings.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".ui.SettingsActivity">

    <include layout="@layout/toolbar_actionbar_with_headerbar" />

    <FrameLayout
        android:id="@+id/container"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />
</LinearLayout>

回答2:

As for me, I usually make a ToolbarActivity. Next, if you want your activity to have a toolbar, you just need to YourActivity extends ToolbarActivity.

public class ToolbarActivity extends AppCompatActivity {

    @Override
    public void setContentView(int layoutResID) {
        super.setContentView(R.layout.activity_toolbar);

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        LayoutInflater inflater = LayoutInflater.from(this);
        View contentView = inflater.inflate(layoutResID, null);

        LinearLayout layout = (LinearLayout) findViewById(R.id.layout);
        layout.addView(contentView, new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
    }
}

XML:

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:id="@+id/layout"
    tools:context=".ToolbarActivity" >

    <android.support.v7.widget.Toolbar
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
        android:layout_height="wrap_content"
        android:layout_width="match_parent"
        android:minHeight="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        android:id="@+id/toolbar" />

</LinearLayout>