Android手写签名

手写签名自定义实现，看注释就行了

package com.zhuzi.taobamboo.user_defined;

import android.content.Context;

import android.graphics.Bitmap;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.graphics.Path;

import android.graphics.PorterDuff;

import android.util.AttributeSet;

import android.view.MotionEvent;

import android.view.View;

import androidx.annotation.ColorInt;

import java.io.ByteArrayOutputStream;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.OutputStream;

/**

@ Authoor 刘晨
@ Time 2022/7/14 0014/11:31
@ explain 手写签名

*/

public class PintView extends View {

private Context mContext;

//起点X

private float mX;

//起点Y

private float mY;

//手写画笔

private final Paint mGesturePaint = new Paint();

//路径

private final Path mPath = new Path();

//画布

private Canvas cacheCanvas;

//生成的图片

private Bitmap cachebBitmap;

//画笔宽度 px；

private int mPaintWidth = 10;

//画笔颜色

private int mPenColor = Color.BLACK;

//背景色（指最终签名结果文件的背景颜色，默认为透明色）

private int mBackColor=Color.TRANSPARENT;

private int pintInt = 0;

public PintView(Context context) {

super(context);

init(context);

}

public PintView(Context context, AttributeSet attrs) {

super(context, attrs);

init(context);

}

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

super(context, attrs, defStyleAttr);

init(context);

}

private void init(Context context) {

this.mContext = context;

//设置抗锯齿

mGesturePaint.setAntiAlias(true);

//设置签名笔画样式

mGesturePaint.setStyle(Paint.Style.STROKE);

//设置笔画宽度

mGesturePaint.setStrokeWidth(mPaintWidth);

//设置签名颜色

mGesturePaint.setColor(mPenColor);

}

@Override

protected void onSizeChanged(int w, int h, int oldw, int oldh) {

super.onSizeChanged(w, h, oldw, oldh);

//创建跟view一样大的bitmap，用来保存签名(在控件大小发生改变时调用。)

cachebBitmap = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);

cacheCanvas = new Canvas(cachebBitmap);

cacheCanvas.drawColor(mBackColor);

}

@Override

protected void onDraw(Canvas canvas) {

super.onDraw(canvas);

//画此次笔画之前的签名

canvas.drawBitmap(cachebBitmap, 0, 0, mGesturePaint);

// 通过画布绘制多点形成的图形

canvas.drawPath(mPath, mGesturePaint);

}

@Override

public boolean onTouchEvent(MotionEvent event) {

switch (event.getAction()){

case MotionEvent.ACTION_DOWN:

touchDown(event);

break;

case MotionEvent.ACTION_MOVE:

pintInt++;

touchMove(event);

break;

case MotionEvent.ACTION_UP:
```
         //将路径画到bitmap中，即一次笔画完成才去更新bitmap，而手势轨迹是实时显示在画板上的。
         cacheCanvas.drawPath(mPath, mGesturePaint);
         mPath.reset();
         break;
 }
 // 更新绘制
 invalidate();
 return true;
```
}

// 手指点下屏幕时调用

private void touchDown(MotionEvent event) {

// 重置绘制路线

mPath.reset();

float x = event.getX();

float y = event.getY();

mX = x;

mY = y;

// mPath绘制的绘制起点

mPath.moveTo(x,y);

}

// 手指在屏幕上滑动时调用

private void touchMove(MotionEvent event) {

final float x = event.getX();

final float y = event.getY();

final float previousX = mX;

final float previousY = mY;

final float dx = Math.abs(x – previousX);

final float dy = Math.abs(y – previousY);

// 两点之间的距离大于等于3时，生成贝塞尔绘制曲线

if (dx >= 3 || dy >= 3) {

// 设置贝塞尔曲线的操作点为起点和终点的一半

float cX = (x + previousX) / 2;

float cY = (y + previousY) / 2;

// 二次贝塞尔，实现平滑曲线；previousX, previousY为操作点，cX, cY为终点

mPath.quadTo(previousX, previousY, cX, cY);

// 第二次执行时，第一次结束调用的坐标值将作为第二次调用的初始坐标值

mX = x;

mY = y;

}

}

/**
- 清除画板
  
  */
  
  public void clear() {
  
  if (cacheCanvas != null) {
  
  pintInt = 0;
  
  //更新画板信息
  
  mGesturePaint.setColor(mPenColor);
  
  cacheCanvas.drawColor(mBackColor, PorterDuff.Mode.CLEAR);
  
  mGesturePaint.setColor(mPenColor);
  
  invalidate();
  
  }
  
  }
/**
- 用来记录会话次数，用来判断用户是否签字
- @return
  
  */
  
  public int getPinInt(){
  
  return pintInt;
  
  }
/**
- 保存画板
- @param path 保存到路径
  
  */
  
  public void save(String path) throws IOException {
  
  save(path, false, 0);
  
  }
/**
- 保存画板
- @param path 保存到路径
- @param clearBlank 是否清除边缘空白区域
- @param blank 要保留的边缘空白距离
  
  */
  
  public void save(String path, boolean clearBlank, int blank) throws IOException {
  
  Bitmap bitmap=cachebBitmap;
  
  //BitmapUtil.createScaledBitmapByHeight(srcBitmap, 300);// 压缩图片
  
  if (clearBlank) {
  
  bitmap = clearBlank(bitmap, blank);
  
  }
  
  ByteArrayOutputStream bos = new ByteArrayOutputStream();
  
  bitmap.compress(Bitmap.CompressFormat.PNG, 100, bos);
  
  byte[] buffer = bos.toByteArray();
  
  if (buffer != null) {
  
  File file = new File(path);
  
  if (file.exists()) {
  
  file.delete();
  
  }
  
  OutputStream outputStream = new FileOutputStream(file);
  
  outputStream.write(buffer);
  
  outputStream.close();
  
  }
  
  }
/**
- 保存画板
- @param clearBlank 是否清除边缘空白区域
- @param blank 要保留的边缘空白距离
  
  */
  
  public Bitmap saveToBitmap(boolean clearBlank, int blank){
  
  Bitmap bitmap=cachebBitmap;
  
  //BitmapUtil.createScaledBitmapByHeight(srcBitmap, 300);// 压缩图片
  
  if (clearBlank) {
  
  bitmap = clearBlank(bitmap, blank);
  
  }
  
  // int width = bitmap.getWidth();
  
  // int height = bitmap.getHeight();
  
  // int w;
  
  // int h;
  
  // if(width>2
  
  height){
  
  // w = width -(width – 2
  
  height);
  
  // h = height;
  
  // } else {
  
  // w = width;
  
  // h = height – (height – width/2);
  
  // }
  
  // return ThumbnailUtils.extractThumbnail(bitmap,w,h);
  
  return bitmap;
  
  }
/**
- 获取画板的bitmap
- @return
  
  */
  
  public Bitmap getBitMap()
  
  {
  
  destroyDrawingCache();
  
  setDrawingCacheEnabled(true);
  
  return getDrawingCache();
  
  }
/**
- 逐行扫描清楚边界空白。
- @param bp
- @param blank 边距留多少个像素
- @return
  
  */
  
  private Bitmap clearBlank(Bitmap bp, int blank) {
  
  int HEIGHT = bp.getHeight();
  
  int WIDTH = bp.getWidth();
  
  int top = 0, left = 0, right = 0, bottom = 0;
  
  int[] pixs = new int[WIDTH];
  
  boolean isStop;
  
  //扫描上边距不等于背景颜色的第一个点
  
  for (int y = 0; y < HEIGHT; y++) {
  
  bp.getPixels(pixs, 0, WIDTH, 0, y, WIDTH, 1);
  
  isStop = false;
  
  for (int pix : pixs) {
  
  if (pix != mBackColor) {
  
  top = y;
  
  isStop = true;
  
  break;
  
  }
  
  }
  
  if (isStop) {
  
  break;
  
  }
  
  }
  
  //扫描下边距不等于背景颜色的第一个点
  
  for (int y = HEIGHT – 1; y >= 0; y–) {
  
  bp.getPixels(pixs, 0, WIDTH, 0, y, WIDTH, 1);
  
  isStop = false;
  
  for (int pix : pixs) {
  
  if (pix != mBackColor) {
  
  bottom = y;
  
  isStop = true;
  
  break;
  
  }
  
  }
  
  if (isStop) {
  
  break;
  
  }
  
  }
  
  pixs = new int[HEIGHT];
  
  //扫描左边距不等于背景颜色的第一个点
  
  for (int x = 0; x < WIDTH; x++) {
  
  bp.getPixels(pixs, 0, 1, x, 0, 1, HEIGHT);
  
  isStop = false;
  
  for (int pix : pixs) {
  
  if (pix != mBackColor) {
  
  left = x;
  
  isStop = true;
  
  break;
  
  }
  
  }
  
  if (isStop) {
  
  break;
  
  }
  
  }
  
  //扫描右边距不等于背景颜色的第一个点
  
  for (int x = WIDTH – 1; x > 0; x–) {
  
  bp.getPixels(pixs, 0, 1, x, 0, 1, HEIGHT);
  
  isStop = false;
  
  for (int pix : pixs) {
  
  if (pix != mBackColor) {
  
  right = x;
  
  isStop = true;
  
  break;
  
  }
  
  }
  
  if (isStop) {
  
  break;
  
  }
  
  }
  
  if (blank < 0) {
  
  blank = 0;
  
  }
  
  //计算加上保留空白距离之后的图像大小
  
  left = left – blank > 0 ? left – blank : 0;
  
  top = top – blank > 0 ? top – blank : 0;
  
  right = right + blank > WIDTH – 1 ? WIDTH – 1 : right + blank;
  
  bottom = bottom + blank > HEIGHT – 1 ? HEIGHT – 1 : bottom + blank;
  
  //防止创建null的bitmap 引发的崩溃
  
  if (left
  
  0&&top
  
  0&&right
  
  0&&bottom
  
  0){
  
  left=1;
  
  top=1;
  
  right=351;
  
  bottom=251;
  
  }
  
  return Bitmap.createBitmap(bp, left, top, right – left, bottom – top);
  
  }
/**
- 设置画笔宽度默认宽度为10px
- @param mPaintWidth
  
  */
  
  public void setPaintWidth(int mPaintWidth) {
  
  mPaintWidth = mPaintWidth > 0 ? mPaintWidth : 10;
  
  this.mPaintWidth = mPaintWidth;
  
  mGesturePaint.setStrokeWidth(mPaintWidth);
}

public void setBackColor(@ColorInt int backColor)

{

mBackColor=backColor;

}

/**
- 设置画笔颜色
- @param mPenColor
  
  */
  
  public void setPenColor(int mPenColor) {
  
  this.mPenColor = mPenColor;
  
  mGesturePaint.setColor(mPenColor);
  
  }
  
  }

原文链接：https://blog.csdn.net/lc_wanshi/article/details/126156097

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