Android本地驗證碼的生成代碼

Posted on by

android客戶端生成本地驗證碼主要用來限制用戶隨意按請求按鈕，其實該示例也是來對自定義view的練練手而已，先給出效果圖吧

其中可定制：

＊幹擾線數目
＊幹擾點數目
＊背景顏色
＊驗證碼字體大小及字數

相信以上可以滿足一般的需要瞭吧，不夠的話可自行添加，下面就來講實現的步驟瞭

繼承view，重寫構造方法，並初始化所需參數

public class ValidationCode extends View {

 private Paint mTextPaint;//文字畫筆
 private Paint mPointPaint;//幹擾點畫筆
 private Paint mPathPaint;//幹擾線畫筆
 private Paint mBitmapPaint;//Bitmap圖畫筆
 private String mCodeString;//隨機驗證碼
 private int mCodeCount;//驗證碼位數
 private float mTextSize;//驗證碼字符大小
 private int mPointNumber;//幹擾點數目
 private int mLineNumber;//幹擾線數目
 private int mBackGround;//背景顏色
 private float mTextWidth;//驗證碼字符串的顯示寬度
 private static int mWidth;//控件的寬度
 private static int mHeight;//控件的高度
 private static Random mRandom = new Random();
 private Bitmap bitmap = null;//生成驗證碼圖片


 public ValidationCode(Context context) {
  this(context, null);
 }

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

 /**
  * 獲取佈局文件中的值
  */
 private void getAttrValues(Context context, AttributeSet attrs) {
  TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.ValidationCode);
  mCodeCount = typedArray.getInteger(R.styleable.ValidationCode_CodeCount, 4);
  mPointNumber = typedArray.getInteger(R.styleable.ValidationCode_PointNumber, 100);
  mLineNumber = typedArray.getInteger(R.styleable.ValidationCode_LineNumber, 2);
  mTextSize = typedArray.getDimension(R.styleable.ValidationCode_CodeTextSize, 20);
  mBackGround = typedArray.getColor(R.styleable.ValidationCode_BackGround,Color.WHITE);
  typedArray.recycle();
 }

 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
  super.onMeasure(widthMeasureSpec, heightMeasureSpec);
  setMeasuredDimension(measureWidth(widthMeasureSpec), measureHeight(heightMeasureSpec));

 }

 /**
  * 初始化畫筆
  */
 private void init() {
  //生成隨機數字和字母組合
  mCodeString = getValidationCode(mCodeCount);
  //初始化文字畫筆
  mTextPaint = new Paint();
  mTextPaint.setStrokeWidth(3);
  mTextPaint.setTextSize(mTextSize);
  //初始化幹擾點畫筆
  mPointPaint = new Paint();
  mPointPaint.setStrokeWidth(4);
  mPointPaint.setStrokeCap(Paint.Cap.ROUND);//設置斷點處為圓形
  //初始化幹擾線畫筆
  mPathPaint = new Paint();
  mPathPaint.setStrokeWidth(5);
  mPathPaint.setColor(Color.GRAY);
  mPathPaint.setStyle(Paint.Style.STROKE);//設置畫筆為空心
  mPathPaint.setStrokeCap(Paint.Cap.ROUND);//設置斷點處為圓形
  //初始化Bitmap畫筆
  mBitmapPaint = new Paint();
  mBitmapPaint.setColor(Color.RED);
  //取得驗證碼字符串顯示的寬度值
  mTextWidth = mTextPaint.measureText(mCodeString);

 }
}

getAttrValues方法是用來配置自定義的屬性，需要在 values 中新建 * attrs.xml * 文件，並加上自定義的屬性，如下：

<?xml version="1.0" encoding="utf-8"?>
<resources>
 <declare-styleable name="ValidationCode">
  <attr name="CodeCount" format="integer"/>
  <attr name="PointNumber" format="integer"/>
  <attr name="LineNumber" format="integer"/>
  <attr name="CodeTextSize" format="dimension"/>
  <attr name="BackGround" format="color"/>
 </declare-styleable>
</resources>

onMeasure方法則是在你需要對自定義的view的大小做出處理時，通過setMeasuredDimension設置該控件大小，下面給出重新定義的寬高代碼塊

/**
* 對view的寬高進行重新定義
*/
private int measureWidth(int measureSpec) {
 int result = 0;
 int specMode = MeasureSpec.getMode(measureSpec);
 int specSize = MeasureSpec.getSize(measureSpec);

 if (specMode == MeasureSpec.EXACTLY) {
  result = specSize;
 } else {
  result = (int) (mTextWidth * 2.0f);
  if (specMode == MeasureSpec.AT_MOST) {
   result = Math.min(result, specSize);
  }
 }
 return result;
}

private int measureHeight(int measureSpec) {
 int result = 0;

 int specMode = MeasureSpec.getMode(measureSpec);
 int specSize = MeasureSpec.getSize(measureSpec);

 if (specMode == MeasureSpec.EXACTLY) {
  result = specSize;
 } else {
  result = (int) (mTextWidth / 1.5f);
  if (specMode == MeasureSpec.AT_MOST) {
   result = Math.min(result, specSize);
  }
 }
 return result;
}

重寫onDraw()，繪制圖形

1、繪制驗證碼文本字符串，幹擾點，幹擾線，生成驗證碼的bitmap圖 

/**
 * 獲取驗證碼
 *
 * @param length 生成隨機數的長度
 * @return
 */
public static String getValidationCode(int length) {
 String val = "";
 Random random = new Random();
 for (int i = 0; i < length; i++) {
  //字母或數字
  String code = random.nextInt(2) % 2 == 0 ? "char" : "num";
  //字符串
  if ("char".equalsIgnoreCase(code)) {
   //大寫或小寫字母
   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));
  }
 }
 return val;
}

/**
 * 生成幹擾點
 */
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);
}

/**
 * 生成幹擾線
 */
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);
}

/**
 1. 繪制驗證碼並返回
 */
private Bitmap generateValidate(){
 if(bitmap != null && !bitmap.isRecycled()){
  //回收並且置為null
  bitmap.recycle();
  bitmap = null;
 }
 //創建圖片和畫佈
 Bitmap sourceBitmap = Bitmap.createBitmap(mWidth,mHeight, Bitmap.Config.ARGB_8888);
 Canvas canvas = new Canvas(sourceBitmap);

 //畫背景顏色
 canvas.drawColor(mBackGround);

 //畫上驗證碼
 int length = mCodeString.length();
 float charLength = mTextWidth / length;
 for (int i = 1; i <= length; i++) {
  int offsetDegree = mRandom.nextInt(15);
  //這裡隻會產生0和1，如果是1那麼正旋轉正角度，否則旋轉負角度
  offsetDegree = mRandom.nextInt(2) == 1 ? offsetDegree : -offsetDegree;
  canvas.save();
  canvas.rotate(offsetDegree, mWidth / 2, mHeight / 2);
  //給畫筆設置隨機顏色
  mTextPaint.setARGB(255, mRandom.nextInt(200) + 20, mRandom.nextInt(200) + 20,
    mRandom.nextInt(200) + 20);
  canvas.drawText(String.valueOf(mCodeString.charAt(i - 1)), (i - 1) * charLength * 1.6f + 30,
    mHeight * 2 / 3f, mTextPaint);
  canvas.restore();
 }

 //產生幹擾效果1 －－ 幹擾點
 for (int i = 0; i < mPointNumber; i++) {
  mPointPaint.setARGB(255, mRandom.nextInt(200) + 20, mRandom.nextInt(200) + 20,
    mRandom.nextInt(200) + 20);
  drawPoint(canvas, mPointPaint);
 }

 //生成幹擾效果2 －－ 幹擾線
 for (int i = 0; i < mLineNumber; i++) {
  mPathPaint.setARGB(255, mRandom.nextInt(200) + 20, mRandom.nextInt(200) + 20,
    mRandom.nextInt(200) + 20);
  drawLine(canvas, mPathPaint);
 }

 canvas.save();
 return sourceBitmap;
}

2、實現onDraw()方法，繪畫出驗證碼

@Override
protected void onDraw(Canvas canvas) {
 super.onDraw(canvas);

 //獲取控件的寬和高
 mHeight = getHeight();
 mWidth = getWidth();

 if(bitmap == null){
  bitmap = generateValidate();
 }
 canvas.drawBitmap(bitmap,0,0,mBitmapPaint);
}

添加觸摸事件，點擊切換驗證碼

@Override
public boolean onTouchEvent(MotionEvent event) {
 switch (event.getAction()) {
  case MotionEvent.ACTION_DOWN:
   mCodeString = getValidationCode(mCodeCount);
   bitmap = generateValidate();
   invalidate();
   break;
  default:
   break;
 }
 return super.onTouchEvent(event);
}

添加公開使用方法

我們總是需要提供給用戶調用的方法，判斷驗證碼是否一致之類的，方便用戶進一步的操作，這裡提供個幾個方法

/**
 * 判斷驗證碼是否一致
 *
 * @String CodeString
 * 這裡忽略大小寫
 */
public Boolean isEqualsIgnoreCase(String CodeString) {
 return mCodeString.equalsIgnoreCase(CodeString);
}

/**
 * 判斷驗證碼是否一致
 * 不忽略大小寫
 */
public Boolean isEquals(String CodeString) {
 return mCodeString.equals(CodeString);
}

/**
 * 外界控件調用刷新驗證碼圖片
 */
public void refresh(){
 mCodeString = getValidationCode(mCodeCount);
 bitmap = generateValidate();
 invalidate();
}

以上就是生成本地驗證碼的一個簡單的自定義view步驟，這裡就給出源碼地址，有需要的就去看看。

以上就是本文的全部內容，希望對大傢的學習有所幫助，也希望大傢多多支持WalkonNet。

推薦閱讀：