使用xml在android TextView中使用自定义字体 [英] Using custom font in android TextView using xml

问题描述

我已将自定义字体文件添加到我的资产/字体文件夹.我如何从我的 XML 中使用它?

I have added a custom font file to my assets/fonts folder. How do I use it from my XML?

我可以从代码中使用它，如下所示:

I can use it from code as follows:

TextView text = (TextView) findViewById(R.id.textview03);
Typeface tf = Typeface.createFromAsset(getAssets(), "fonts/Molot.otf");
text.setTypeface(tf);

我不能使用 android:typeface="/fonts/Molot.otf" 属性从 XML 中执行此操作吗?

Can't I do it from XML using an android:typeface="/fonts/Molot.otf" attribute?

推荐答案

简短回答:否.Android 没有内置支持通过 XML 将自定义字体应用于文本小部件.

Short answer: No. Android doesn't have built-in support for applying custom fonts to text widgets through XML.

但是，有一个解决方法并不难实施.

However, there's a workaround that's not terribly difficult to implement.

第一

您需要定义自己的样式.在您的/res/values 文件夹中，打开/创建 attrs.xml 文件并添加一个声明样式的对象，如下所示:

You'll need to define your own stylable. In your /res/values folder, open/create the attrs.xml file and add a declare-styleable object like so:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="FontText">
        <attr name="typefaceAsset" format="string"/>
    </declare-styleable>
</resources>

第二

假设您想经常使用这个小部件，您应该为加载的 Typeface 对象设置一个简单的缓存，因为从内存中动态加载它们可能需要时间.类似的东西:

Assuming you want to use this widget often, you should set up a simple cache for the loaded Typeface objects, since loading them from memory on the fly can take time. Something like:

public class FontManager {
    private static FontManager instance;

    private AssetManager mgr;

    private Map<String, Typeface> fonts;

    private FontManager(AssetManager _mgr) {
        mgr = _mgr;
        fonts = new HashMap<String, Typeface>();
    }

    public static void init(AssetManager mgr) {
        instance = new FontManager(mgr);
    }

    public static FontManager getInstance() {
        if (instance == null) {
            // App.getContext() is just one way to get a Context here
            // getContext() is just a method in an Application subclass
            // that returns the application context
            AssetManager assetManager = App.getContext().getAssets();
            init(assetManager);
        }
        return instance;
    }

    public Typeface getFont(String asset) {
        if (fonts.containsKey(asset))
            return fonts.get(asset);

        Typeface font = null;

        try {
            font = Typeface.createFromAsset(mgr, asset);
            fonts.put(asset, font);
        } catch (Exception e) {

        }

        if (font == null) {
            try {
                String fixedAsset = fixAssetFilename(asset);
                font = Typeface.createFromAsset(mgr, fixedAsset);
                fonts.put(asset, font);
                fonts.put(fixedAsset, font);
            } catch (Exception e) {

            }
        }

        return font;
    }

    private String fixAssetFilename(String asset) {
        // Empty font filename?
        // Just return it. We can't help.
        if (TextUtils.isEmpty(asset))
            return asset;

        // Make sure that the font ends in '.ttf' or '.ttc'
        if ((!asset.endsWith(".ttf")) && (!asset.endsWith(".ttc")))
            asset = String.format("%s.ttf", asset);

        return asset;
    }
}

这将允许您使用 .ttc 文件扩展名，但它未经测试.

This one will allow you to use .ttc file extensions, but it's untested.

第三

创建一个子类 TextView 的新类.此特定示例考虑了定义的 XML 字体(bold、italic 等)并将其应用于字体(假设您使用的是 .ttc 文件).

Create a new class that subclasses TextView. This particular example takes into account the defined XML typeface (bold, italic, etc.) and apply it to the font (assuming you're using a .ttc file).

/**
 * TextView subclass which allows the user to define a truetype font file to use as the view's typeface.
 */
public class FontText extends TextView {
    public FontText(Context context) {
        this(context, null);
    }

    public FontText(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public FontText(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);

        if (isInEditMode())
            return;

        TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.FontText);

        if (ta != null) {
            String fontAsset = ta.getString(R.styleable.FontText_typefaceAsset);

            if (!TextUtils.isEmpty(fontAsset)) {
                Typeface tf = FontManager.getInstance().getFont(fontAsset);
                int style = Typeface.NORMAL;
                float size = getTextSize();

                if (getTypeface() != null)
                    style = getTypeface().getStyle();

                if (tf != null)
                    setTypeface(tf, style);
                else
                    Log.d("FontText", String.format("Could not create a font from asset: %s", fontAsset));
            }
        }
    }
}

终于

用完全限定的类名替换 XML 中 TextView 的实例.像声明 Android 命名空间一样声明您的自定义命名空间.请注意，typefaceAsset"应指向/assets 目录中包含的 .ttf 或 .ttc 文件.

Replace the instances of TextView in your XML with the fully qualified class name. Declare your custom namespace just like you would the Android namespace. Note that the "typefaceAsset" should point to a .ttf or .ttc file contained in your /assets directory.

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:custom="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.example.FontText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="This is a custom font text"
        custom:typefaceAsset="fonts/AvenirNext-Regular.ttf"/>
</RelativeLayout>

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