android实现图片验证码方法解析(自绘控件)

 <declare-styleable name="VerifyCode"> <attr name="codeTextSize" format="dimension"/> <attr name="codeBackground" format="color"/> <attr name="codeLength" format="integer"/> <attr name="isContainChar" format="boolean"/> <attr name="pointNum" format="integer"/> <attr name="linNum" format="integer"/> </declare-styleable>

import android.content.Context;import android.content.res.TypedArray;import android.graphics.Bitmap;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.PointF;import android.graphics.Rect;import android.util.AttributeSet;import android.util.TypedValue;import android.view.MotionEvent;import android.view.View;import java.util.Random;/** * 类描述:自定义验证码 * 创建者：lb */public class VerifyCode extends View { private String mCodeText;//文本内容 private int mCodeTextSize;//文本大小 private int mCodeLength;//验证码长度 private int mCodeBackground;//背景色 private boolean isContainChar;//验证码是否包含字母 private int mPointNum;//干扰点数 private int mLineNum;//干扰线数 private Paint mPaint;//画笔 private Rect mBound;//绘制范围 private Bitmap bitmap;//验证码图片 private static Random mRandom = new Random(); private static int mWidth;//控件的宽度 private static int mHeight;//控件的高度 public VerifyCode(Context context) { super(context); } public VerifyCode(Context context, AttributeSet attrs) { super(context, attrs); initAttrValues(context,attrs); initData(); } /** * 初始化属性集合 * @param context * @param attrs */ private void initAttrValues(Context context, AttributeSet attrs){ // //获取在AttributeSet中定义的 VerifyCode 中声明的属性的集合 TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.VerifyCode); //获取TypeArray的长度 int count=typedArray.getIndexCount(); for (int i=0;i<count;i++){  //获取此项属性的ID  int index=typedArray.getIndex(i);  switch (index){  case R.styleable.VerifyCode_codeTextSize:   // 默认设置为16sp，TypeValue类 px转sp 一个转换类   mCodeTextSize =typedArray.getDimensionPixelSize(index,(int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, 16, getResources().getDisplayMetrics()));   break;  case R.styleable.VerifyCode_codeBackground:mCodeBackground=typedArray.getColor(index,Color.WHITE);   break;  case R.styleable.VerifyCode_codeLength:   mCodeLength=typedArray.getInteger(index,4);   break;  case R.styleable.VerifyCode_isContainChar:   isContainChar=typedArray.getBoolean(index,false);   break;  case R.styleable.VerifyCode_pointNum:   mPointNum=typedArray.getInteger(index,100);   break;  case R.styleable.VerifyCode_linNum:   mLineNum=typedArray.getInteger(index,3);   break;  } } //Recycles the TypedArray, to be re-used by a later caller //官方解释：回收TypedArray 以便后面的使用者重用 typedArray.recycle(); } /** * 初始化数据 */ private void initData(){ mCodeText=getValidationCode(mCodeLength,isContainChar); mPaint=new Paint(); mPaint.setAntiAlias(true); mBound=new Rect(); //计算文字所在矩形，可以得到宽高 mPaint.getTextBounds(mCodeText,0, mCodeText.length(),mBound); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); //获取控件宽高的显示模式 int widthMode=MeasureSpec.getMode(widthMeasureSpec); int heightMode=MeasureSpec.getMode(heightMeasureSpec); //获取宽高的尺寸值 固定值的宽度 int widthSize=MeasureSpec.getSize(widthMeasureSpec); int heightSize=MeasureSpec.getSize(heightMeasureSpec); //设置宽高默认为建议的最小宽高 int width= getDefaultSize(getSuggestedMinimumWidth(),widthMeasureSpec) ; int height=getDefaultSize(getSuggestedMinimumHeight(),heightMeasureSpec);// MeasureSpec父布局传递给后代的布局要求 包含 确定大小和三种模式// EXACTLY：一般是设置了明确的值或者是MATCH_PARENT// AT_MOST：表示子布局限制在一个最大值内，一般为WARP_CONTENT// UNSPECIFIED：表示子布局想要多大就多大，很少使用 if (widthMode==MeasureSpec.EXACTLY){  width=widthSize; }else{  mPaint.setTextSize(mCodeTextSize);  mPaint.getTextBounds(mCodeText,0,mCodeText.length(),mBound);  float textWidth=mBound.width();  int tempWidth=(int)(getPaddingLeft()+textWidth+getPaddingRight());  width=tempWidth; } if (heightMode == MeasureSpec.EXACTLY) {  height = heightSize; } else {  mPaint.setTextSize(mCodeTextSize);  mPaint.getTextBounds(mCodeText, 0, mCodeText.length(), mBound);  float textHeight = mBound.height();  int tempHeight = (int) (getPaddingTop() + textHeight + getPaddingBottom());  height = tempHeight; } //设置测量的宽高 setMeasuredDimension(width,height); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); mWidth=getWidth(); mHeight=getHeight(); if (bitmap==null){  bitmap=createBitmapValidate(); } canvas.drawBitmap(bitmap,0,0,mPaint); } @Override public boolean onTouchEvent(MotionEvent event) { switch (event.getAction()){  case MotionEvent.ACTION_DOWN:  refresh();  break; } return super.onTouchEvent(event); } /** * 创建图片验证码 * @return */ private Bitmap createBitmapValidate(){ if(bitmap != null && !bitmap.isRecycled()){  //回收并且置为null  bitmap.recycle();  bitmap = null; } //创建图片 Bitmap sourceBitmap=Bitmap.createBitmap(mWidth,mHeight, Bitmap.Config.ARGB_8888); //创建画布 Canvas canvas=new Canvas(sourceBitmap); //画上背景颜色 canvas.drawColor(mCodeBackground); //初始化文字画笔 mPaint.setStrokeWidth(3f); mPaint.setTextSize(mCodeTextSize); //测量验证码字符串显示的宽度值 float textWidth=mPaint.measureText(mCodeText); //画上验证码 int length = mCodeText.length(); //计算一个字符的所占位置 float charLength = textWidth / length; for (int i = 1; i <= length; i++) {  int offsetDegree = mRandom.nextInt(15);  //这里只会产生0和1，如果是1那么正旋转正角度，否则旋转负角度  offsetDegree = mRandom.nextInt(2) == 1 ? offsetDegree : -offsetDegree;  //用来保存Canvas的状态。save之后，可以调用Canvas的平移、放缩、旋转、错切、裁剪等操作。  canvas.save();  //设置旋转  canvas.rotate(offsetDegree, mWidth / 2, mHeight / 2);  //给画笔设置随机颜色  mPaint.setARGB(255, mRandom.nextInt(200) + 20, mRandom.nextInt(200) + 20,   mRandom.nextInt(200) + 20);  //设置字体的绘制位置  canvas.drawText(String.valueOf(mCodeText.charAt(i - 1)), (i - 1) * charLength+5,   mHeight * 4 / 5f, mPaint);  //用来恢复Canvas之前保存的状态。防止save后对Canvas执行的操作对后续的绘制有影响。  canvas.restore(); } //重新设置画笔 mPaint.setARGB(255, mRandom.nextInt(200) + 20, mRandom.nextInt(200) + 20,  mRandom.nextInt(200) + 20); mPaint.setStrokeWidth(1); //产生干扰效果1 －－ 干扰点 for (int i = 0; i < mPointNum; i++) {  drawPoint(canvas, mPaint); } //生成干扰效果2 －－ 干扰线 for (int i = 0; i < mLineNum; i++) {  drawLine(canvas, mPaint); } return sourceBitmap; } /** * 生成干扰点 */ private static void drawPoint(Canvas canvas, Paint paint) { PointF pointF = new PointF(mRandom.nextInt(mWidth) + 10, mRandom.nextInt(mHeight) + 10); canvas.drawPoint(pointF.x, pointF.y, paint); } /** * 生成干扰线 */ private static void drawLine(Canvas canvas, Paint paint) { int startX = mRandom.nextInt(mWidth); int startY = mRandom.nextInt(mHeight); int endX = mRandom.nextInt(mWidth); int endY = mRandom.nextInt(mHeight); canvas.drawLine(startX, startY, endX, endY, paint); } /** * 获取验证码 * * @param length 生成随机数的长度 * @param contains 是否包含字符串 * @return */ public String getValidationCode(int length,boolean contains) { String val = ""; Random random = new Random(); for (int i = 0; i < length; i++) {  if (contains){  //字母或数字  String code = random.nextInt(2) % 2 == 0 ? "char" : "num";  //字符串  if ("char".equalsIgnoreCase(code)) {   //大写或小写字母   int choice = random.nextInt(2) % 2 == 0 ? 65 : 97;   val += (char) (choice + random.nextInt(26));  } else if ("num".equalsIgnoreCase(code)) {   val += String.valueOf(random.nextInt(10));  }  }else{  val += String.valueOf(random.nextInt(10));  } } return val; } /** *判断验证码是否一致 忽略大小写 */ public Boolean isEqualsIgnoreCase(String CodeString) { return mCodeText.equalsIgnoreCase(CodeString); } /** * 判断验证码是否一致 不忽略大小写 */ public Boolean isEquals(String CodeString) { return mCodeText.equals(CodeString); } /** * 提供外部调用的刷新方法 */ public void refresh(){ mCodeText= getValidationCode(mCodeLength,isContainChar); bitmap = createBitmapValidate(); invalidate(); }}