更改康斯坦丁·布罗夫的答案，因为在我的情况下不起作用：

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <shape android:shape="rectangle">
            <solid android:color="@android:color/white" />
            <stroke android:width="2dip" android:color="#4fa5d5"/>
            <corners android:radius="7dp"/>
        </shape>
    </item>
</selector>

compileSdkVersion 26（Android 8.0），minSdkVersion 21（Android 5.0），targetSdkV版本26，实现“com.android.support:appcompat-v7:26.1.0”，等级：4.1

我找到了一种更好的方法来在TextView周围添加边框。

使用九块图像作为背景。它非常简单，SDK附带了一个制作9补丁图像的工具，而且它绝对不需要编码。

链接是http://developer.android.com/guide/topics/graphics/2d-graphics.html#nine-补丁。

我只是在寻找一个类似的答案——它可以通过Stroke和以下覆盖来完成：

@Override
public void draw(Canvas canvas, MapView mapView, boolean shadow) {

Paint strokePaint = new Paint();
strokePaint.setARGB(255, 0, 0, 0);
strokePaint.setTextAlign(Paint.Align.CENTER);
strokePaint.setTextSize(16);
strokePaint.setTypeface(Typeface.DEFAULT_BOLD);
strokePaint.setStyle(Paint.Style.STROKE);
strokePaint.setStrokeWidth(2);

Paint textPaint = new Paint();
textPaint.setARGB(255, 255, 255, 255);
textPaint.setTextAlign(Paint.Align.CENTER);
textPaint.setTextSize(16);
textPaint.setTypeface(Typeface.DEFAULT_BOLD);

canvas.drawText("Some Text", 100, 100, strokePaint);
canvas.drawText("Some Text", 100, 100, textPaint);

super.draw(canvas, mapView, shadow); 
}

简单的方法是为TextView添加视图。底部边框线示例：

<LinearLayout android:orientation="vertical"
              android:layout_width="fill_parent"
              android:layout_height="fill_parent">
    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:layout_marginLeft="10dp"
        android:text="@string/title"
        android:id="@+id/title_label"
        android:gravity="center_vertical"/>
    <View
        android:layout_width="fill_parent"
        android:layout_height="0.2dp"
        android:id="@+id/separator"
        android:visibility="visible"
        android:background="@android:color/darker_gray"/>

</LinearLayout>

对于其他方向的边框，请调整分隔符视图的位置。

可以通过两种方法设置边框。一种是可绘制的，另一种是编程的。

使用Drawable

<shape>
    <solid android:color="@color/txt_white"/>
    <stroke android:width="1dip" android:color="@color/border_gray"/>
    <corners android:bottomLeftRadius="10dp"
             android:bottomRightRadius="0dp"
             android:topLeftRadius="10dp"
             android:topRightRadius="0dp"/>
    <padding android:bottom="0dip"
             android:left="0dip"
             android:right="0dip"
             android:top="0dip"/>
</shape>

程序化的

public static GradientDrawable backgroundWithoutBorder(int color) {

    GradientDrawable gdDefault = new GradientDrawable();
    gdDefault.setColor(color);
    gdDefault.setCornerRadii(new float[] { radius, radius, 0, 0, 0, 0,
                                           radius, radius });
    return gdDefault;
}

我通过扩展文本视图并手动绘制边框解决了这个问题。我甚至添加了这样的选项，您可以选择边框是虚线还是虚线。

public class BorderedTextView extends TextView {
        private Paint paint = new Paint();
        public static final int BORDER_TOP = 0x00000001;
        public static final int BORDER_RIGHT = 0x00000002;
        public static final int BORDER_BOTTOM = 0x00000004;
        public static final int BORDER_LEFT = 0x00000008;

        private Border[] borders;

        public BorderedTextView(Context context, AttributeSet attrs, int defStyle) {
            super(context, attrs, defStyle);
            init();
        }

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

        public BorderedTextView(Context context) {
            super(context);
            init();
        }
        private void init(){
            paint.setStyle(Paint.Style.STROKE);
            paint.setColor(Color.BLACK);
            paint.setStrokeWidth(4);        
        }
        @Override
        protected void onDraw(Canvas canvas) {
            super.onDraw(canvas);
            if(borders == null) return;

            for(Border border : borders){
                paint.setColor(border.getColor());
                paint.setStrokeWidth(border.getWidth());

                if(border.getStyle() == BORDER_TOP){
                    canvas.drawLine(0, 0, getWidth(), 0, paint);                
                } else
                if(border.getStyle() == BORDER_RIGHT){
                    canvas.drawLine(getWidth(), 0, getWidth(), getHeight(), paint);
                } else
                if(border.getStyle() == BORDER_BOTTOM){
                    canvas.drawLine(0, getHeight(), getWidth(), getHeight(), paint);
                } else
                if(border.getStyle() == BORDER_LEFT){
                    canvas.drawLine(0, 0, 0, getHeight(), paint);
                }
            }
        }

        public Border[] getBorders() {
            return borders;
        }

        public void setBorders(Border[] borders) {
            this.borders = borders;
        }
}

边框类：

public class Border {
    private int orientation;
    private int width;
    private int color = Color.BLACK;
    private int style;
    public int getWidth() {
        return width;
    }
    public void setWidth(int width) {
        this.width = width;
    }
    public int getColor() {
        return color;
    }
    public void setColor(int color) {
        this.color = color;
    }
    public int getStyle() {
        return style;
    }
    public void setStyle(int style) {
        this.style = style;
    }
    public int getOrientation() {
        return orientation;
    }
    public void setOrientation(int orientation) {
        this.orientation = orientation;
    }
    public Border(int Style) {
        this.style = Style;
    }
}

希望这对某人有所帮助：）