1.生成图片背景

public class WaterMarkUtil {
    private DensityUtil densityUtil;
    // 声明单例
    private volatile static WaterMarkUtil mInstance = null;

    public static WaterMarkUtil getInstance() {
        if (mInstance == null) {
            synchronized (SpUtils.class) {
                if (mInstance == null) {
                    mInstance = new WaterMarkUtil();
                }
            }
        }
        return mInstance;
    }

    //设置背景
    public void setWaterMarkTextBg(View view, Context gContext, String gText) {
        view.setBackground(drawTextToBitmap(gContext, gText));
    }

    /**
     * 生成水印文字图片
     */

    public BitmapDrawable drawTextToBitmap(Context gContext, String gText) {
        gText = gText + " ";

        Bitmap waterMarkBitmap = ACache.get(gContext).getAsBitmap(gText);
        if (waterMarkBitmap != null && !waterMarkBitmap.isRecycled()) {
            BitmapDrawable drawable = new BitmapDrawable(waterMarkBitmap);

            drawable.setTileModeXY(Shader.TileMode.REPEAT, Shader.TileMode.REPEAT);

            drawable.setDither(true);

            return drawable;

        }
        try {
            Bitmap bitmap = Bitmap.createBitmap(AppTools.dip2px(420), AppTools.dip2px(400), Bitmap.Config.ARGB_8888);

            Canvas canvas = new Canvas(bitmap);

            canvas.drawColor(getColorPrimary(gContext));

            Paint paint = new Paint();

            paint.setColor(Color.LTGRAY);

            paint.setAlpha(80);

            paint.setAntiAlias(true);

            paint.setTextAlign(Paint.Align.LEFT);

            paint.setTextSize(AppTools.dip2px(70));

            Path path = new Path();

            path.moveTo(AppTools.dip2px(0), AppTools.dip2px(300));

            path.lineTo(AppTools.dip2px(210) * 2, AppTools.dip2px(0));

            canvas.drawTextOnPath(gText, path, AppTools.dip2px(0), AppTools.dip2px(50), paint);

//            canvas.save(Canvas.ALL_SAVE_FLAG);
            canvas.save();

            canvas.restore();

            ACache.get(gContext).put(gText, bitmap);

            BitmapDrawable drawable = new BitmapDrawable(bitmap);

            drawable.setTileModeXY(Shader.TileMode.REPEAT, Shader.TileMode.REPEAT);

            drawable.setDither(true);
            return drawable;

        } catch (Exception e) {
        }

        return null;

    }

    public int getColorPrimary(Context context){
        TypedValue typedValue = new TypedValue();
        context.getTheme().resolveAttribute(R.attr.colorPrimary, typedValue, true);
        return typedValue.data;
    }
}

2.代码使用

//获取对象
WaterMarkUtil instance = WaterMarkUtil.getInstance();
//设置名字 以及 手机号后4位
instance.setWaterMarkTextBg(relWatermark, getContext(), user.name  + "  " +   user.telephone.substring(user.telephone.length() - 4));

3.布局使用

<RelativeLayout
        android:id="@+id/rel_watermark"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_below="@id/header">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:clipToPadding="false"
        android:overScrollMode="never"
        android:paddingBottom="@dimen/home_tab_widget_height"
        android:background="@color/transparent"
        android:scrollbars="none" />
    </RelativeLayout>