电子合同签名 自定义View

最近有一个电子合同的需求 需要用户手写签字 保存签名图片 

先上图

主要实现自定义View

public class GestureSignatureView extends View {

 private static final String TAG = "GestureSignatureView";
    private Path mPath;//绘制路径
    private Paint mPaint;// 绘制画笔
    private Canvas mCanvas;//背景画布
    private Bitmap mMBitmap;//背景bitmap
    private boolean isTouchedSignature = false;//是否签名

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

    public GestureSignatureView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public GestureSignatureView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        initPaint();
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        Log.d(TAG, "onMeasure: 测量的宽高：" + getMeasuredWidth() + "-----------" + getMeasuredHeight());
    }

    @Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        super.onLayout(changed, left, top, right, bottom);
        mMBitmap = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);
        mCanvas = new Canvas(mMBitmap);
        mCanvas.drawColor(Color.TRANSPARENT);
        mCanvas.setDrawFilter(new PaintFlagsDrawFilter(0, Paint.ANTI_ALIAS_FLAG | Paint.FILTER_BITMAP_FLAG));
        isTouchedSignature = false;
    }

    private void initPaint() {
        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mPaint.setColor(Color.BLACK);
        mPaint.setStrokeWidth(10.0f);
        mPaint.setStrokeCap(Paint.Cap.ROUND);
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setStrokeJoin(Paint.Join.ROUND);
        mPaint.setDither(true);
        mPath = new Path();

    }

    @Override
    protected void onDraw(Canvas canvas) {
        canvas.setDrawFilter(new PaintFlagsDrawFilter(0, Paint.ANTI_ALIAS_FLAG | Paint.FILTER_BITMAP_FLAG));
        canvas.drawBitmap(mMBitmap, 0, 0, mPaint);
        // 通过画布绘制多点形成的图形
        canvas.drawPath(mPath, mPaint);
    }

    private float[] downPoint = new float[2];

    private float[] previousPoint = new float[2];

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        downPoint[0] = event.getX();
        downPoint[1] = event.getY();
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                previousPoint[0] = downPoint[0];
                previousPoint[1] = downPoint[1];
                mPath.moveTo(downPoint[0], downPoint[1]);
                break;
            case MotionEvent.ACTION_MOVE:
                float dX = Math.abs(downPoint[0] - previousPoint[0]);
                float dY = Math.abs(downPoint[1] - previousPoint[1]);

                // 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 = (downPoint[0] + previousPoint[0]) / 2;
                    float cY = (downPoint[1] + previousPoint[1]) / 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(previousPoint[0], previousPoint[1], 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
                    previousPoint[0] = downPoint[0];
                    previousPoint[1] = downPoint[1];
                }
//                float moveCurrentX = downPoint[0];
//                float moveCurrentY = downPoint[1];
//                mPath.quadTo(moveCurrentX, moveCurrentY, downPoint[0], downPoint[1]);
                break;
            case MotionEvent.ACTION_UP:
                mCanvas.drawPath(mPath, mPaint);
                mPath.reset();
                break;
        }


        invalidate();
        return true;
    }


    // 缩放

    public static Bitmap resizeImage(Bitmap bitmap, int width, int height) {
        int originWidth = bitmap.getWidth();
        int originHeight = bitmap.getHeight();

        float scaleWidth = ((float) width) / originWidth;
        float scaleHeight = ((float) height) / originHeight;

        Matrix matrix = new Matrix();
        matrix.postScale(scaleWidth, scaleHeight);
        Bitmap resizedBitmap = Bitmap.createBitmap(bitmap, 0, 0, originWidth,
                originHeight, matrix, true);
        return resizedBitmap;
    }

    public Bitmap getPaintBitmap() {
        return resizeImage(mMBitmap, 320, 480);
    }

    public void clear() {
        if (mCanvas != null) {
            isTouchedSignature = false;
            mPath.reset();
            mCanvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);
            invalidate();
        }
    }

    /**
     * 保存画板
     *
     * @param path 保存到路劲
     */

    public void save(String path) throws IOException {
        save(path, false, 0);
    }

    /**
     * 保存画板
     *
     * @param path       保存到路劲
     * @param clearBlank 是否清楚空白区域
     * @param blank      边缘空白区域
     */
    public void save(String path, boolean clearBlank, int blank) throws IOException {

        Bitmap bitmap = mMBitmap;
        //BitmapUtil.createScaledBitmapByHeight(srcBitmap, 300);//  压缩图片
        if (clearBlank) {
            bitmap = clearBlank(mMBitmap, blank);
        }
        Bitmap newBitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(newBitmap);
        canvas.drawColor(Color.WHITE);
        canvas.setDrawFilter(new PaintFlagsDrawFilter(0, Paint.ANTI_ALIAS_FLAG | Paint.FILTER_BITMAP_FLAG));
        canvas.drawBitmap(bitmap, 0, 0, null);
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        newBitmap.compress(Bitmap.CompressFormat.JPEG, 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();
            scanMediaFile(file);
        }
    }

    /**
     * 是否有签名
     *
     * @return
     */
    public boolean getTouched() {
        return isTouchedSignature;
    }

    /**
     * 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;
        for (int y = 0; y < HEIGHT; y++) {
            bp.getPixels(pixs, 0, WIDTH, 0, y, WIDTH, 1);
            isStop = false;
            for (int pix : pixs) {
                if (pix != Color.TRANSPARENT) {
                    top = y;
                    isStop = true;
                    break;
                }
            }
            if (isStop) {
                break;
            }
        }
        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 != Color.TRANSPARENT) {
                    bottom = y;
                    isStop = true;
                    break;
                }
            }
            if (isStop) {
                break;
            }
        }
        pixs = new int[HEIGHT];
        for (int x = 0; x < WIDTH; x++) {
            bp.getPixels(pixs, 0, 1, x, 0, 1, HEIGHT);
            isStop = false;
            for (int pix : pixs) {
                if (pix != Color.TRANSPARENT) {
                    left = x;
                    isStop = true;
                    break;
                }
            }
            if (isStop) {
                break;
            }
        }
        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 != Color.TRANSPARENT) {
                    right = x;
                    isStop = true;
                    break;
                }
            }
            if (isStop) {
                break;
            }
        }
        if (blank < 0) {
            blank = 0;
        }
        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;
        return Bitmap.createBitmap(bp, left, top, right - left, bottom - top);
    }

    private void scanMediaFile(File photo) {
        Intent mediaScanIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
        Uri contentUri = Uri.fromFile(photo);
        mediaScanIntent.setData(contentUri);
        getContext().sendBroadcast(mediaScanIntent);
    }

}

希望能帮助到您

 

 

本文地址：https://blog.csdn.net/Originality_special/article/details/107151943