android - 如何为 TextView xml 布局设置字体

Question

我创建了一个名称为 def_list 的 XML 布局。我为它分配了一个 ID，即 def_list_textview。我在 Assets 文件夹中放置了一个名为 bn.ttf 的字体。

XML 布局如下:

<?xml version="1.0" encoding="utf-8"?>
    <TextView xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/def_list_textview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="right" >
    </TextView>

但是当我使用代码为其设置字体时:

def_list_tv = (TextView)findViewById(R.id.def_list_textview);
Typeface tf = Typeface.createFromAsset(this.getAssets(), "fonts/bn.ttf");
def_list_tv.setTypeface(tf);

我在 LogCat 中得到一个 nullPointerException。我不知道为什么。

这是我的 LogCat:

12-26 17:14:56.496: E/AndroidRuntime(1254): FATAL EXCEPTION: main
12-26 17:14:56.496: E/AndroidRuntime(1254): java.lang.RuntimeException: Unable to start activity ComponentInfo{net.adeveloper.handydic/net.adeveloper.dic.PortDef}: java.lang.NullPointerException
12-26 17:14:56.496: E/AndroidRuntime(1254):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
12-26 17:14:56.496: E/AndroidRuntime(1254):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
12-26 17:14:56.496: E/AndroidRuntime(1254):     at android.app.ActivityThread.access$1500(ActivityThread.java:117)
12-26 17:14:56.496: E/AndroidRuntime(1254):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
12-26 17:14:56.496: E/AndroidRuntime(1254):     at android.os.Handler.dispatchMessage(Handler.java:99)
12-26 17:14:56.496: E/AndroidRuntime(1254):     at android.os.Looper.loop(Looper.java:123)
12-26 17:14:56.496: E/AndroidRuntime(1254):     at android.app.ActivityThread.main(ActivityThread.java:3683)
12-26 17:14:56.496: E/AndroidRuntime(1254):     at java.lang.reflect.Method.invokeNative(Native Method)
12-26 17:14:56.496: E/AndroidRuntime(1254):     at java.lang.reflect.Method.invoke(Method.java:507)
12-26 17:14:56.496: E/AndroidRuntime(1254):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
12-26 17:14:56.496: E/AndroidRuntime(1254):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
12-26 17:14:56.496: E/AndroidRuntime(1254):     at dalvik.system.NativeStart.main(Native Method)
12-26 17:14:56.496: E/AndroidRuntime(1254): Caused by: java.lang.NullPointerException
12-26 17:14:56.496: E/AndroidRuntime(1254):     at net.adeveloper.dic.PortDef.onCreate(PortDef.java:53)
12-26 17:14:56.496: E/AndroidRuntime(1254):     at     android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
12-26 17:14:56.496: E/AndroidRuntime(1254):     at     android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
12-26 17:14:56.496: E/AndroidRuntime(1254):     ... 11 more

Answer 1

问题可能出在

this.getAssets()

getAssets() 是来自 Context 的方法，因此尝试传递上下文对象而不是 this

尝试

Typeface tf = Typeface.createFromAsset(getContext().getAssets(), "fonts/bn.ttf");

或

Typeface tf = Typeface.createFromAsset(mContext.getAssets(), "fonts/bn.ttf");

这里mContext是Context的对象

编辑:

请检查以下自定义 TextView 是否可以帮助您

public class CustomTextView extends TextView{
  public CustomTextView(Context context,AttributeSet attrs,int defStyle){
    super(context,attrs,defStyle);
    init();
  }
  public CustomTextView(Context context,AttributeSet attrs){
    super(context,attrs);
    init();
  }
  public CustomTextView(Context context){
    super(context);
    init();
  }

  private void init(){
    if(!isInEditMode()){
        Typeface tf = Typeface.createFromAsset(getContext().getAssets(), "fonts/bn.ttf");
        setTypeface(tf);
    }
  }
}

我在我之前的一个项目中使用过这个类