我只是在onCreate()函数中做了以下工作:

TypefaceSpan typefaceSpan = new TypefaceSpan("font_to_be_used");
SpannableString str = new SpannableString("toolbar_text");
str.setSpan(typefaceSpan,0, str.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
getSupportActionBar().setTitle(str);

我正在使用支持库，如果你不使用它们，我猜你应该切换到getActionBar()而不是getSupportActionBar()。

在Android Studio 3中，您可以按照以下说明添加自定义字体https://developer.android.com/guide/topics/ui/look-and-feel/fonts-in-xml.html，然后在“font_to_be_used”中使用您新添加的字体

    ActionBar actionBar = getSupportActionBar();
    TextView tv = new TextView(getApplicationContext());
    Typeface typeface = ResourcesCompat.getFont(this, R.font.monotype_corsiva);
    RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(
            RelativeLayout.LayoutParams.MATCH_PARENT, // Width of TextView
            RelativeLayout.LayoutParams.WRAP_CONTENT); // Height of TextView
    tv.setLayoutParams(lp);
    tv.setText("Your Text"); // ActionBar title text
    tv.setTextSize(25);
    tv.setTextColor(Color.WHITE);
    tv.setTypeface(typeface, typeface.ITALIC);
    actionBar.setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM);
    actionBar.setCustomView(tv);

为了补充@Sam_D的答案，我必须这样做才能使它工作:

this.setTitle("my title!");
((TextView)v.findViewById(R.id.title)).setText(this.getTitle());
TextView title = ((TextView)v.findViewById(R.id.title));
title.setEllipsize(TextUtils.TruncateAt.MARQUEE);
title.setMarqueeRepeatLimit(1);
// in order to start strolling, it has to be focusable and focused
title.setFocusable(true);
title.setSingleLine(true);
title.setFocusableInTouchMode(true);
title.requestFocus();

这似乎有点过分-两次引用v.f entviewbyid (R.id.title)) -但这是唯一的方法，它会让我这样做。

以下代码将适用于所有版本。我确实在gingerbread设备和JellyBean设备上检查了这一点

 private void actionBarIdForAll()
    {
        int titleId = 0;

        if(Build.VERSION.SDK_INT>=Build.VERSION_CODES.HONEYCOMB)
        {
            titleId = getResources().getIdentifier("action_bar_title", "id", "android");
        }
        else
        {
          // This is the id is from your app's generated R class when ActionBarActivity is used for SupportActionBar

            titleId = R.id.action_bar_title;
        }

        if(titleId>0)
        {
            // Do whatever you want ? It will work for all the versions.

            // 1. Customize your fonts
            // 2. Infact, customize your whole title TextView

            TextView titleView = (TextView)findViewById(titleId);
            titleView.setText("RedoApp");
            titleView.setTextColor(Color.CYAN);
        }
    }

试试这个

TextView headerText= new TextView(getApplicationContext());
RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(ActionBar.LayoutParams.WRAP_CONTENT, ActionBar.LayoutParams.WRAP_CONTENT);
headerText.setLayoutParams(lp);
headerText.setText("Welcome!");
headerText.setTextSize(20);
headerText.setTextColor(Color.parseColor("#FFFFFF"));
Typeface tf = Typeface.createFromAsset(getAssets(), "fonts/wesfy_regular.ttf");
headerText.setTypeface(tf);
getSupportActionBar().setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM);
getSupportActionBar().setCustomView(headerText);

没有自定义的文本视图是必需的!

首先，在你的java代码中禁用工具栏中的标题: getSupportActionBar () .setDisplayShowTitleEnabled(假);

然后，只需在工具栏内添加一个TextView:

<android.support.v7.widget.Toolbar
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="?attr/colorPrimary"
    app:popupTheme="@style/AppTheme.PopupOverlay">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/app_name"
        android:textSize="18sp"
        android:fontFamily="@font/roboto" />

    </android.support.v7.widget.Toolbar>