我们需要使用反射来实现这一点

final int titleId = activity.getResources().getIdentifier("action_bar_title", "id", "android");

    final TextView title;
    if (activity.findViewById(titleId) != null) {
        title = (TextView) activity.findViewById(titleId);
        title.setTextColor(Color.BLACK);
        title.setTextColor(configs().getColor(ColorKey.GENERAL_TEXT));
        title.setTypeface(configs().getTypeface());
    } else {
        try {
            Field f = bar.getClass().getDeclaredField("mTitleTextView");
            f.setAccessible(true);
            title = (TextView) f.get(bar);
            title.setTextColor(Color.BLACK);
            title.setTypeface(configs().getTypeface());
        } catch (NoSuchFieldException e) {
        } catch (IllegalAccessException e) {
        }
    }

如果你想在整个活动中设置所有textview的字体，你可以使用这样的东西:

public static void setTypefaceToAll(Activity activity)
{
    View view = activity.findViewById(android.R.id.content).getRootView();
    setTypefaceToAll(view);
}

public static void setTypefaceToAll(View view)
{
    if (view instanceof ViewGroup)
    {
        ViewGroup g = (ViewGroup) view;
        int count = g.getChildCount();
        for (int i = 0; i < count; i++)
            setTypefaceToAll(g.getChildAt(i));
    }
    else if (view instanceof TextView)
    {
        TextView tv = (TextView) view;
        setTypeface(tv);
    }
}

public static void setTypeface(TextView tv)
{
    TypefaceCache.setFont(tv, TypefaceCache.FONT_KOODAK);
}

TypefaceCache:

import java.util.TreeMap;

import android.graphics.Typeface;
import android.widget.TextView;

public class TypefaceCache {

    //Font names from asset:
    public static final String FONT_ROBOTO_REGULAR = "fonts/Roboto-Regular.ttf";
    public static final String FONT_KOODAK = "fonts/Koodak.ttf";

    private static TreeMap<String, Typeface> fontCache = new TreeMap<String, Typeface>();

    public static Typeface getFont(String fontName) {
        Typeface tf = fontCache.get(fontName);
        if(tf == null) {
            try {
                tf = Typeface.createFromAsset(MyApplication.getAppContext().getAssets(), fontName);
            }
            catch (Exception e) {
                return null;
            }
            fontCache.put(fontName, tf);
        }
        return tf;
    }

    public static void setFont(TextView tv, String fontName)
    {
        tv.setTypeface(getFont(fontName));
    }
}

int titleId = getResources().getIdentifier("action_bar_title", "id",
            "android");
    TextView yourTextView = (TextView) findViewById(titleId);
    yourTextView.setTextColor(getResources().getColor(R.color.black));
    yourTextView.setTypeface(face);

书法库让你通过应用程序主题设置自定义字体，这也适用于操作栏。

<style name="AppTheme" parent="android:Theme.Holo.Light.DarkActionBar">
<item name="android:textViewStyle">@style/AppTheme.Widget.TextView</item>
</style>

<style name="AppTheme.Widget"/>

<style name="AppTheme.Widget.TextView" parent="android:Widget.Holo.Light.TextView">
   <item name="fontPath">fonts/Roboto-ThinItalic.ttf</item>
</style>

激活书法所需要的是将它附加到你的活动上下文:

@Override
protected void attachBaseContext(Context newBase) {
    super.attachBaseContext(new CalligraphyContextWrapper(newBase));
}

默认的自定义属性是fontPath，但是您可以通过在Application类中使用calligraphy hyconfig . builder初始化它来为路径提供您自己的自定义属性。不鼓励使用android:fontFamily。

使用新的工具栏在支持库设计你自己的动作栏或使用下面的代码

膨胀的Textview不是一个好的选择，尝试可扩展的字符串生成器

Typeface font2 = Typeface.createFromAsset(getAssets(), "fonts/<your font in assets folder>");   
SpannableStringBuilder SS = new SpannableStringBuilder("MY Actionbar Tittle");
SS.setSpan (new CustomTypefaceSpan("", font2), 0, SS.length(),Spanned.SPAN_EXCLUSIVE_INCLUSIVE);
actionBar.setTitle(ss);

复制以下类

public class CustomTypefaceSpan extends TypefaceSpan{

    private final Typeface newType;

    public CustomTypefaceSpan(String family, Typeface type) {
        super(family);
        newType = type;
    }

    @Override
    public void updateDrawState(TextPaint ds) {
        applyCustomTypeFace(ds, newType);
    }

    @Override
    public void updateMeasureState(TextPaint paint) {
        applyCustomTypeFace(paint, newType);
    }

    private static void applyCustomTypeFace(Paint paint, Typeface tf) {
        int oldStyle;
        Typeface old = paint.getTypeface();
        if (old == null) {
            oldStyle = 0;
        } else {
            oldStyle = old.getStyle();
        }

        int fake = oldStyle & ~tf.getStyle();
        if ((fake & Typeface.BOLD) != 0) {
            paint.setFakeBoldText(true);
        }

        if ((fake & Typeface.ITALIC) != 0) {
            paint.setTextSkewX(-0.25f);
        }

        paint.setTypeface(tf);
    }

}

更新正确答案。

首先:将标题设置为false，因为我们正在使用自定义视图

    actionBar.setDisplayShowTitleEnabled(false);

第二步:创建titleview.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"
   android:background="@android:color/transparent" >

    <TextView
       android:id="@+id/title"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:layout_centerVertical="true"
       android:layout_marginLeft="10dp"
       android:textSize="20dp"
       android:maxLines="1"
       android:ellipsize="end"
       android:text="" />

</RelativeLayout>

最后:

//font file must be in the phone db so you have to create download file code
//check the code on the bottom part of the download file code.

   TypeFace font = Typeface.createFromFile("/storage/emulated/0/Android/data/"   
    + BuildConfig.APPLICATION_ID + "/files/" + "font name" + ".ttf");

    if(font != null) {
        LayoutInflater inflator = LayoutInflater.from(this);
        View v = inflator.inflate(R.layout.titleview, null);
        TextView titleTv = ((TextView) v.findViewById(R.id.title));
        titleTv.setText(title);
        titleTv.setTypeface(font);
        actionBar.setCustomView(v);
    } else {
        actionBar.setDisplayShowTitleEnabled(true);
        actionBar.setTitle("  " + title); // Need to add a title
    }

下载字体文件:因为我把文件存储到cloudinary，所以我有链接下载它。

/**downloadFile*/
public void downloadFile(){
    String DownloadUrl = //url here
    File file = new File("/storage/emulated/0/Android/data/" + BuildConfig.APPLICATION_ID + "/files/");
    File[] list = file.listFiles();
    if(list == null || list.length <= 0) {
        BroadcastReceiver onComplete = new BroadcastReceiver() {
            @Override
            public void onReceive(Context context, Intent intent) {
                try{
                    showContentFragment(false);
                } catch (Exception e){
                }
            }
        };

        registerReceiver(onComplete, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));
        DownloadManager.Request request = new DownloadManager.Request(Uri.parse(DownloadUrl));
        request.setVisibleInDownloadsUi(false);
        request.setDestinationInExternalFilesDir(this, null, ModelManager.getInstance().getCurrentApp().getRegular_font_name() + ".ttf");
        DownloadManager manager = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
        manager.enqueue(request);
    } else {
        for (File files : list) {
            if (!files.getName().equals("font_name" + ".ttf")) {
                BroadcastReceiver onComplete = new BroadcastReceiver() {
                    @Override
                    public void onReceive(Context context, Intent intent) {
                        try{
                            showContentFragment(false);
                        } catch (Exception e){
                        }
                    }
                };

                registerReceiver(onComplete, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));
                DownloadManager.Request request = new DownloadManager.Request(Uri.parse(DownloadUrl));
                request.setVisibleInDownloadsUi(false);
                request.setDestinationInExternalFilesDir(this, null, "font_name" + ".ttf");
                DownloadManager manager = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
                manager.enqueue(request);
            } else {
                showContentFragment(false);
                break;
            }
        }
    }
}