工作學習中要使用到這個功能,在網上查找了些例子,但都不符合要求,做了一些完善:1.顏色爲rgb256的;2.生成的文字間距不會超過圖片寬度
代碼如下:
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.Log;
import java.util.Random;
/**
* Created by Jackie on 2015/12/1.
* 用於圖片驗證碼的工具類
*/
public class CodeUtils {
private static final char[] CHARS = {
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
'n', 'o', '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', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'
};
private static CodeUtils mCodeUtils;
private int mPaddingLeft, mPaddingTop;
private StringBuilder mBuilder = new StringBuilder();
private Random mRandom = new Random();
private String code;
private int RandomInt;
//Default Settings
private static final int DEFAULT_CODE_LENGTH = 4;//驗證碼的長度 這裏是4位
private static final int DEFAULT_FONT_SIZE = 60;//字體大小
private static final int DEFAULT_LINE_NUMBER = 3;//多少條幹擾線
private static final int BASE_PADDING_LEFT = 20; //左邊距
private static final int RANGE_PADDING_LEFT = 35;//左邊距範圍值
private static final int BASE_PADDING_TOP = 42;//上邊距
private static final int RANGE_PADDING_TOP = 15;//上邊距範圍值
private static final int DEFAULT_WIDTH = 200;//默認寬度.圖片的總寬
private static final int DEFAULT_HEIGHT = 100;//默認高度.圖片的總高
private static final int DEFAULT_COLOR = 0xDF;//默認背景顏色值
public static CodeUtils getInstance() {
if(mCodeUtils == null) {
mCodeUtils = new CodeUtils();
}
return mCodeUtils;
}
//生成驗證碼圖片
public Bitmap createBitmap() {
mPaddingLeft = 0; //每次生成驗證碼圖片時初始化
mPaddingTop = 0;
Bitmap bitmap = Bitmap.createBitmap(DEFAULT_WIDTH, DEFAULT_HEIGHT, Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
//生成的驗證碼
code = createCode();
canvas.drawColor(Color.rgb(DEFAULT_COLOR, DEFAULT_COLOR, DEFAULT_COLOR));
Paint paint = new Paint();
paint.setTextSize(DEFAULT_FONT_SIZE);
for (int i = 0; i < code.length(); i++) {
randomTextStyle(paint);
randomPadding();
Log.i("println","CodeUtils-"+code.charAt(i)+"字體寬:"+paint.measureText(String.valueOf(code.charAt(i)))+" 左側間距:"+mPaddingLeft);
while(paint.measureText(String.valueOf(code.charAt(i)))+mPaddingLeft>DEFAULT_WIDTH){
mPaddingLeft=mPaddingLeft-RandomInt;
randomPadding();
Log.i("println","CodeUtils-寬度超出,重新生成間距");
}
canvas.drawText(code.charAt(i) + "" , mPaddingLeft, mPaddingTop, paint);
}
//干擾線
for (int i = 0; i < DEFAULT_LINE_NUMBER; i++) {
drawLine(canvas, paint);
}
canvas.save(Canvas.ALL_SAVE_FLAG);//保存
canvas.restore();
return bitmap;
}
//獲取生成的驗證碼
public String getCode() {
return code;
}
//生成驗證碼
public String createCode() {
mBuilder.delete(0, mBuilder.length()); //使用之前首先清空內容
for (int i = 0; i < DEFAULT_CODE_LENGTH; i++) {
mBuilder.append(CHARS[mRandom.nextInt(CHARS.length)]);
}
return mBuilder.toString();
}
//生成干擾線
private void drawLine(Canvas canvas, Paint paint) {
int color = randomColor();
int startX = mRandom.nextInt(DEFAULT_WIDTH);
int startY = mRandom.nextInt(DEFAULT_HEIGHT);
int stopX = mRandom.nextInt(DEFAULT_WIDTH);
int stopY = mRandom.nextInt(DEFAULT_HEIGHT);
paint.setStrokeWidth(1);
paint.setColor(color);
canvas.drawLine(startX, startY, stopX, stopY, paint);
}
//隨機顏色
private int randomColor() {
return randomColor(1);
}
private int randomColor(int rate) {
Random random = new Random();
int red = random.nextInt(256) / rate;
int green = random.nextInt(256) / rate;
int blue = random.nextInt(256) / rate;
return Color.rgb(red, green, blue);
}
//隨機文本樣式
private void randomTextStyle(Paint paint) {
int color = randomColor();
paint.setColor(color);
paint.setFakeBoldText(mRandom.nextBoolean()); //true爲粗體,false爲非粗體
float skewX = mRandom.nextInt(11) / 10;
skewX = mRandom.nextBoolean() ? skewX : -skewX;
paint.setTextSkewX(skewX); //float類型參數,負數表示右斜,整數左斜
// paint.setUnderlineText(true); //true爲下劃線,false爲非下劃線
// paint.setStrikeThruText(true); //true爲刪除線,false爲非刪除線
}
//隨機間距
private void randomPadding() {
RandomInt=BASE_PADDING_LEFT +mRandom.nextInt(RANGE_PADDING_LEFT);
mPaddingLeft += RandomInt;
mPaddingTop = BASE_PADDING_TOP + mRandom.nextInt(RANGE_PADDING_TOP);
}
}
其中使用ImageView.setImageBitmap(CodeUtils.getInstance().createBitmap())將生成的圖片載入ImageView,再使用CodeUtils.getInstance().createBitmap()獲取String型的驗證碼。
謹以此記。