1.通过定义XML方式实现

1. <TextView   
2.         android:id="@+id/txtMsg"  
3.         android:layout_width="wrap_content"  
4.         android:layout_height="wrap_content"         android:textSize="19px"  
5.         android:gravity="center_horizontal"  
6.         android:text="测试文字"  
7.         android:drawablePadding="-20px"  //设置字体和图片之间的距离， 这是实现文字叠加显示在图片之上的关键点~  
8.         android:drawableTop="@drawable/ic_launcher" // 设置图片显示在文字的上方  
9.         />  

1. TextView v = new TextView(this.getApplicationContext());  
2.  v.setCompoundDrawablePadding(-20);      
3. v.setGravity(Gravity.CENTER_HORIZONTAL);     
4. Drawable image = getResources().getDrawable(icons[i]);  
5.   
6. image.setBounds(0, 0, image.getMinimumWidth(), image.getMinimumHeight());//非常重要，必须设置，否则图片不会显示  
7. v.setCompoundDrawables(null,image, null, null);              
8. v.setText("测试文字");    
9. v.setTextSize(TypedValue.COMPLEX_UNIT_PX,19);//设置字体大小为19px  
10.  
11.  

Paint mp = new paint();
mp.setTypeface(Typeface.DEFAULT_BOLD)

Paint mp = new Paint();
Typeface font = Typeface.create(Typeface.SANS_SERIF,Typeface.BOLD);
p.setTypeface( font );

Paint mp = new Paint();
mp.setFakeBoldText(true); //true为粗体，false为非粗体
mp.setTextSkewX(-0.5f);  //float类型参数，负数表示右斜，整数左斜
mp.setUnderlineText(true); //true为下划线，false为非下划线
mp.setStrikeThruText(true); //true为删除线，false为非删除线

mp.setTextSize(); //设置字体大小，int型，如12
mp.setstrokeWidth(w); //设置线宽，float型，如2.5f，默认绘文本无需设置（默认值好像为0），但假如设置了，再绘制文本的时候一定要恢复到0

private void drawNewBitmap(ImageView imageView,String str) {
   Bitmap photo = BitmapFactory.decodeResource(this.getResources(),R.drawable.background);
   int width = photo.getWidth();
   int hight = photo.getHeight();
   //建立一个空的Bitmap
   Bitmap icon = Bitmap.createBitmap(width,hight,Bitmap.Config.ARGB_8888);
   // 初始化画布绘制的图像到icon上
   Canvas canvas = new Canvas(icon);
   // 建立画笔
   Paint photoPaint = new Paint(); 
   // 获取更清晰的图像采样，防抖动
   photoPaint.setDither(true); 
   // 过滤一下，抗剧齿
   photoPaint.setFilterBitmap(true);
   
   Rect src = new Rect(0,photo.getWidth(),photo.getHeight());// 创建一个指定的新矩形的坐标
   Rect dst = new Rect(0,width,hight);// 创建一个指定的新矩形的坐标
   canvas.drawBitmap(photo,src,dst,photoPaint);// 将photo 缩放或则扩大到dst使用的填充区photoPaint
　　　　　　//自定义的画笔
   TextPaint textPaint=myTextPaint();
 　　　　 drawText(canvas,textPaint,str,45,hight/5,width);
   
   canvas.save(Canvas.ALL_SAVE_FLAG);
   canvas.restore();
   
   imageView.setimageBitmap(icon);
   saveMyBitmap(this,icon);
 }

//设置画笔的字体和颜色
 public TextPaint myTextPaint(){
   
   TextPaint textPaint = new TextPaint(Paint.ANTI_ALIAS_FLAG | Paint.DEV_KERN_TEXT_FLAG);// 设置画笔
   int TEXT_SIZE = Math.round(25 * getRATIO());
   textPaint.setTextSize(TEXT_SIZE);// 字体大小
    textPaint.setTypeface(Typeface.DEFAULT_BOLD);// 采用默认的宽度
    textPaint.setColor(Color.argb(255,94,38,18));// 采用的颜色
    return textPaint;

//写入文字，自动换行的方法
 public void drawText(Canvas canvas,TextPaint Paint,String textString,int x,int y,int width) { 
  //int Width=Math.round(width* getRATIO());
  int start_x=Math.round(x * getRATIO());
  int start_y=Math.round(y * getRATIO());
  StaticLayout staticLayout=new StaticLayout(textString,Paint,width-start_x*2,Alignment.ALIGN_norMAL,1.5f,0.0f,false); 
   
  //绘制的位置 
  canvas.translate(start_x,start_y); 
  staticLayout.draw(canvas); 
 }

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package net.yt.yuncare.widgets;

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;

import java.lang.*;
import java.util.Random;

/**
 * Created by lenovo on 2018/5/14.
 */

public class Code {

    //随机数数组
    private static final char[] CHARS = {
            ''2'', ''3'', ''4'', ''5'', ''6'', ''7'', ''8'', ''9'',
            ''a'', ''b'', ''c'', ''d'', ''e'', ''f'', ''g'', ''h'', ''j'', ''k'', ''m'',
            ''n'', ''p'', ''q'', ''r'', ''s'', ''t'', ''u'', ''v'', ''w'', ''x'', ''y'', ''z'',
            ''A'', ''B'', ''C'', ''D'', ''E'', ''F'', ''G'', ''H'', ''I'', ''J'', ''K'', ''L'', ''M'',
            ''N'', ''P'', ''Q'', ''R'', ''S'', ''T'', ''U'', ''V'', ''W'', ''X'', ''Y'', ''Z''
    };

    private static Code bmpCode;

    public static Code getInstance() { //单例模式
        if(bmpCode == null)
            bmpCode = new Code();
        return bmpCode;
    }

    //default settings
    //验证码默认随机数的个数
    private static final int DEFAULT_CODE_LENGTH = 4;
    //默认字体大小
    private static final int DEFAULT_FONT_SIZE = 35;
    //默认线条的条数
    private static final int DEFAULT_LINE_NUMBER = 2;
    //padding值
    private static final int BASE_PADDING_LEFT = 10, RANGE_PADDING_LEFT = 15, BASE_PADDING_TOP = 15, RANGE_PADDING_TOP = 20;
    //验证码的默认宽高
    private static final int DEFAULT_WIDTH = 100, DEFAULT_HEIGHT = 40;

    //settings decided by the layout xml
    //canvas width and height
    private int width = DEFAULT_WIDTH, height = DEFAULT_HEIGHT;

    //random word space and pading_top
    private int base_padding_left = BASE_PADDING_LEFT, range_padding_left = RANGE_PADDING_LEFT,
            base_padding_top = BASE_PADDING_TOP, range_padding_top = RANGE_PADDING_TOP;

    //number of chars, lines; font size
    private int codeLength = DEFAULT_CODE_LENGTH, line_number = DEFAULT_LINE_NUMBER, font_size = DEFAULT_FONT_SIZE;

    //variables
    private String code;
    private int padding_left, padding_top;
    private Random random = new Random();
    //生成验证码图片  在外部Image调用，用setImageBitmap添加图片到ImageView控件中
    public Bitmap createBitmap() {
        padding_left = 0;
        //重点：创建Bt图片
        Bitmap bp = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888); //
        Canvas c = new Canvas(bp);//创建画板导入bt图片

        code = createCode();

        c.drawColor(Color.WHITE);//添加画板背景色为白色
        Paint paint = new Paint();//创建画笔
        paint.setAntiAlias(true);
        paint.setTextSize(font_size);//设置画笔大小
        //画验证码
        for (int i = 0; i < code.length(); i++) {
            randomTextStyle(paint); //画笔传入生成随机样式
            randomPadding();
            c.drawText(code.charAt(i) + "", padding_left, padding_top, paint);
        }
        //画线条
        for (int i = 0; i < line_number; i++) {
            drawLine(c, paint);
        }

        c.save( Canvas.ALL_SAVE_FLAG );//保存
        c.restore();//
        return bp;
    }

    public String getCode() {
        return code;
    }

    //生成验证码
    private String createCode() {
        StringBuilder buffer = new StringBuilder();
        for (int i = 0; i < codeLength; i++) {
            buffer.append(CHARS[random.nextInt(CHARS.length)]);
        }
        return buffer.toString();
    }
    //画干扰线
    private void drawLine(Canvas canvas, Paint paint) {
        int color = randomColor();
        int startX = random.nextInt(width);
        int startY = random.nextInt(height);
        int stopX = random.nextInt(width);
        int stopY = random.nextInt(height);
        paint.setStrokeWidth(1);
        paint.setColor(color);
        canvas.drawLine(startX, startY, stopX, stopY, paint);
    }
    //生成随机颜色
    private int randomColor() {
        return randomColor(1);
    }

    private int randomColor(int rate) {
        int red = random.nextInt(256) / rate;
        int green = random.nextInt(256) / rate;
        int blue = random.nextInt(256) / rate;
        return Color.rgb(red, green, blue);
    }
    //随机生成文字样式，颜色，粗细，倾斜度
    private void randomTextStyle(Paint paint) {
        int color = randomColor();
        paint.setColor(color);
        paint.setFakeBoldText(random.nextBoolean());  //true为粗体，false为非粗体
        //float skewX = random.nextInt(11) / 10;
        //skewX = random.nextBoolean() ? skewX : -skewX;
        //paint.setTextSkewX(skewX); //float类型参数，负数表示右斜，整数左斜
        //paint.setUnderlineText(true); //true为下划线，false为非下划线
        //paint.setStrikeThruText(true); //true为删除线，false为非删除线
    }
    //随机生成padding值
    private void randomPadding() {
        padding_left += base_padding_left + random.nextInt(range_padding_left);
        padding_top = base_padding_top + random.nextInt(range_padding_top);
    }
}