Android-自定义点选文字验证-CFANZ编程社区

setMeasuredDimension(width, height);

/根据画布尺寸生成相同尺寸的背景图/

newBgBitmap = clipBitmap(bgBitmap, width, height);

/根据新的背景图生成填充部分/

srcBitmap = createSmallBitmap(newBgBitmap);

}

设置画笔的混合模式，生成一张自定义形状的图片供填充部分使用

public Bitmap createSmallBitmap(Bitmap var) {

Bitmap bitmap = Bitmap.createBitmap(shadowSize, shadowSize, Bitmap.Config.ARGB_8888);

Canvas canvas1 = new Canvas(bitmap);

canvas1.drawCircle(shadowSize / 2, shadowSize / 2, shadowSize / 2, paintSrc);

/设置混合模式/

paintSrc.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));

/在指定范围随机生成空缺部分坐标，保证空缺部分出现在View右侧/

int min = width / 3;

int max = width - shadowSize / 2 - padding;

Random random = new Random();

shadowLeft = random.nextInt(max) % (max - min + 1) + min;

Rect rect = new Rect(shadowLeft, (height - shadowSize) / 2, shadowSize + shadowLeft, (height + shadowSize) / 2);

RectF rectF = new RectF(0, 0, shadowSize, shadowSize);

canvas1.drawBitmap(var, rect, rectF, paintSrc);

paintSrc.setXfermode(null);

return bitmap;

}

在onDraw()方法中依次画出背景图、空缺部分、填充部分，注意先后顺序（具体细节自行处理，例如阴影、凹凸感等等）

@Override

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

RectF rectF = new RectF(0, 0, width, height);

/画背景图/

canvas.drawBitmap(newBgBitmap, null, rectF, paintSrc);

bgPaint.setColor(Color.parseColor(“#000000”));

/画空缺部分周围阴影/

canvas.drawCircle(shadowLeft + shadowSize / 2, height / 2, shadowSize / 2, bgPaint);

/画空缺部分/

canvas.drawCircle(shadowLeft + shadowSize / 2, height / 2, shadowSize / 2, paintShadow);

Rect rect = new Rect(srcLeft, (height - shadowSize) / 2, shadowSize + srcLeft, (height + shadowSize) / 2);

bgPaint.setColor(Color.parseColor(“#FFFFFF”));

/画填充部分周围阴影/

canvas.drawCircle(srcLeft + shadowSize / 2, height / 2, shadowSize / 2, bgPaint);

/画填充部分/

canvas.drawBitmap(srcBitmap, null, rect, paintSrc);

}

package com.example.qingfengwei.myapplication;

import android.content.Context;

import android.content.res.Resources;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.graphics.BlurMaskFilter;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Matrix;

import android.graphics.Paint;

import android.graphics.PorterDuff;

import android.graphics.PorterDuffXfermode;

import android.graphics.Rect;

import android.graphics.RectF;

import android.util.AttributeSet;

import android.util.Log;

import android.view.MotionEvent;

import android.view.View;

import android.widget.Toast;

import java.util.Random;

public class SlidingVerificationView extends View {

private Bitmap bgBitmap;

private Bitmap newBgBitmap;

private Bitmap srcBitmap;

private Paint paintShadow;

private Paint paintSrc;

private float curX;

private float lastX;

private int dx;

private int shadowSize = dp2px(60);

private int padding = dp2px(40);

private int shadowLeft;

private int srcLeft = padding;

private int width, height;

private Paint bgPaint;

private OnVerifyListener listener;

public SlidingVerificationView(Context context) {

this(context, null);

}

public SlidingVerificationView(Context context, AttributeSet attrs) {

this(context, attrs, 0);

}

public SlidingVerificationView(Context context, AttributeSet attrs, int defStyleAttr) {

super(context, attrs, defStyleAttr);

paintShadow = new Paint();

paintShadow.setAntiAlias(true);

paintShadow.setColor(Color.parseColor(“#AA000000”));

paintSrc = new Paint();

paintSrc.setAntiAlias(true);

paintSrc.setFilterBitmap(true);

paintSrc.setStyle(Paint.Style.FILL_AND_STROKE);

paintSrc.setColor(Color.WHITE);

bgPaint = new Paint();

bgPaint.setMaskFilter(new BlurMaskFilter(5, BlurMaskFilter.Blur.OUTER));

bgPaint.setAntiAlias(true);

bgPaint.setStyle(Paint.Style.FILL);

bgBitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.syzt);

}

public void setVerifyListener(OnVerifyListener listener) {

this.listener = listener;

}

public Bitmap clipBitmap(Bitmap bm, int newWidth, int newHeight) {

int width = bm.getWidth();

int height = bm.getHeight();

float scaleWidth = ((float) newWidth) / width;

float scaleHeight = ((float) newHeight) / height;

Matrix matrix = new Matrix();

matrix.postScale(scaleWidth, scaleHeight);

return Bitmap.createBitmap(bm, 0, 0, width, height, matrix, true);

}