最好的方法是:

TextView tv = findViewById(R.id.textView);
tv.setTypeface(Typeface.DEFAULT_BOLD);

你可以用这个字体

创建一个类名TypefaceTextView并扩展TextView

私有静态Map mTypefaces;

public TypefaceTextView(final Context context) {
    this(context, null);
}

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

public TypefaceTextView(final Context context, final AttributeSet attrs, final int defStyle) {
    super(context, attrs, defStyle);
    if (mTypefaces == null) {
        mTypefaces = new HashMap<String, Typeface>();
    }

    if (this.isInEditMode()) {
        return;
    }

    final TypedArray array = context.obtainStyledAttributes(attrs, styleable.TypefaceTextView);
    if (array != null) {
        final String typefaceAssetPath = array.getString(
                R.styleable.TypefaceTextView_customTypeface);

        if (typefaceAssetPath != null) {
            Typeface typeface = null;

            if (mTypefaces.containsKey(typefaceAssetPath)) {
                typeface = mTypefaces.get(typefaceAssetPath);
            } else {
                AssetManager assets = context.getAssets();
                typeface = Typeface.createFromAsset(assets, typefaceAssetPath);
                mTypefaces.put(typefaceAssetPath, typeface);
            }

            setTypeface(typeface);
        }
        array.recycle();
    }
}

将字体粘贴到资源文件夹中创建的字体文件夹中

<packagename.TypefaceTextView
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="1.5"
        android:gravity="center"
        android:text="TRENDING TURFS"
        android:textColor="#000"
        android:textSize="20sp"
        app:customTypeface="fonts/pompiere.ttf" />**here pompiere.ttf is the font name**

将这些行放在xml的父布局中

 xmlns:app="http://schemas.android.com/apk/res/com.mediasters.wheresmyturf"
xmlns:custom="http://schemas.android.com/apk/res-auto"

如果你在画它，那么这个就可以做到:

TextPaint.setFlags(Paint.FAKE_BOLD_TEXT_FLAG);

textView.setPaintFlags(textView.getPaintFlags() | Paint.FAKE_BOLD_TEXT_FLAG)

要移除，请使用

textView.setPaintFlags(textView.getPaintFlags() & ~Paint.FAKE_BOLD_TEXT_FLAG)

或者用Kotlin:

fun TextView.makeBold() {
    this.paintFlags = this.paintFlags or Paint.FAKE_BOLD_TEXT_FLAG
}

fun TextView.removeBold() {
    this.paintFlags = this.paintFlags and (Paint.FAKE_BOLD_TEXT_FLAG.inv())
}

editText.setTypeface(Typeface.createFromAsset(getAssets(), ttfFilePath));
etitText.setTypeface(et.getTypeface(), Typeface.BOLD);

将字体和样式都设置为粗体。

这是解决方案

TextView questionValue = (TextView) findViewById(R.layout.TextView01);
questionValue.setTypeface(null, Typeface.BOLD);