Android中的自定义字体：java.lang.RuntimeException

Question

I am trying to use a custom font within a TextView of an Android Studio application, but am getting the following error:

It's a null pointer exception; in the below code, txt is null for some reason:

Java :

    TextView txt;

    txt.setText("A");


    txt = (TextView) findViewById(R.id.custom_font);
    Typeface font = Typeface.createFromAsset(getAssets(), "fonts/Grundschrift.ttf");
    txt.setTypeface(font);

XML :

android:id="@+id/custom_font"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="A"

Thanks!

Answer 1

With this part of your,

TextView txt;
txt.setText("A");

implies that you are calling a method setText() in a null object. To use this method, you have to first initialize the TextView.

so change this

TextView txt;
txt.setText("A");

txt = (TextView) findViewById(R.id.custom_font);
Typeface font = Typeface.createFromAsset(getAssets(), "fonts/Grundschrift.ttf");
txt.setTypeface(font);

to

TextView txt; 
txt = (TextView) findViewById(R.id.custom_font);
Typeface font = Typeface.createFromAsset(getAssets(), "fonts/Grundschrift.ttf");
txt.setTypeface(font);
txt.setText("A");

Answer 2

The line: Caused by: java.lang.NullPointerException: Attempt to invoke the method 'void android.widget.TextView.setText(java.lang.CharSequence)... makes me assume that the ploblem is you call txt.setText("A"); before casting txt = (TextView) findViewById(R.id.custom_font); .

Instead you should do like this:

TextView txt = (TextView) findViewById(R.id.custom_font);
txt.setText("A");
Typeface font = Typeface.createFromAsset(getAssets(), "fonts/Grundschrift.ttf");
txt.setTypeface(font);

Answer 3

Try to change your code like the below code:

...
Typeface font = Typeface.createFromAsset(getContext().getAssets(),  "fonts/Grundschrift.ttf");
...

View's getContext() method to get the current context.

Answer 4

You are using txt before initializing, so this one causes a null pointer exception.

Before accessing any variable or object you have to initialize it properly.

like txt = (TextView) findViewById(R.id.custom_font);

txt.setText or something