Android逐字符显示文本动画的问题

我遵循这个解决方案 Android character by character display text animation

我得到了未解决的方法 setContentView

这是打字机类

public class Typewriter extends TextView {


private CharSequence mText;
private int mIndex;
private long mDelay = 500; //Default 500ms delay


public Typewriter(Context context) {
    super(context);
}

public Typewriter(Context context, AttributeSet attrs) {
    super(context, attrs);
}

private Handler mHandler = new Handler();
private Runnable characterAdder = new Runnable() {
    @Override
    public void run() {
        setText(mText.subSequence(0, mIndex++));
        if(mIndex <= mText.length()) {
            mHandler.postDelayed(characterAdder, mDelay);
        }
    }
};

public void animateText(CharSequence text) {
    mText = text;
    mIndex = 0;

    setText("");
    mHandler.removeCallbacks(characterAdder);
    mHandler.postDelayed(characterAdder, mDelay);
}

public void setCharacterDelay(long millis) {
    mDelay = millis;
}
}

然后我尝试使用它

    Typewriter writer = new Typewriter(this);
    setContentView(writer);

    //Add a character every 150ms
    writer.setCharacterDelay(150);
    writer.animateText("Sample String");

我还尝试添加此自定义布局

        <com.mayday.md.common.Typewriter
            android:id="@+id/contact_popup"
            style="@style/wizard_intro_style"
            android:background="#FFFFFF"
            android:textColor="#000000"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="0.24"
            android:text=""
            android:padding="1dp"
            android:paddingLeft="1dp"
            android:paddingTop="1dp"
            android:paddingRight="1dp"
            android:paddingBottom="1dp"
            android:lines="2"
            android:layout_above="@+id/ll_contact_1"
            android:layout_centerHorizontal="true"
            android:width="150dp" />