1 效果
2 源码
/** * 自动上下扫描 */ public class AutoScannerView extends View { private static final String TAG = AutoScannerView.class.getSimpleName(); private Paint maskPaint; private Paint linePaint; private Paint traAnglePaint; private Paint textPaint; private final int maskColor = Color.parseColor("#60000000"); //蒙在摄像头上面区域的半透明颜色 private final int triAngleColor = Color.parseColor("#76EE00"); //边角的颜色 private final int lineColor = Color.parseColor("#FF0000"); //中间线的颜色 private final int textColor = Color.parseColor("#CCCCCC"); //文字的颜色 private final int triAngleLength = dp2px(20); //每个角的点距离 private final int triAngleWidth = dp2px(4); //每个角的点宽度 private final int textMarinTop = dp2px(30); //文字距离识别框的距离 private int lineOffsetCount = 0; public AutoScannerView(Context context, AttributeSet attrs) { super(context, attrs); maskPaint = new Paint(Paint.ANTI_ALIAS_FLAG); maskPaint.setColor(maskColor); traAnglePaint = new Paint(Paint.ANTI_ALIAS_FLAG); traAnglePaint.setColor(triAngleColor); traAnglePaint.setStrokeWidth(triAngleWidth); traAnglePaint.setStyle(Paint.Style.STROKE); linePaint = new Paint(Paint.ANTI_ALIAS_FLAG); linePaint.setColor(lineColor); textPaint = new Paint(Paint.ANTI_ALIAS_FLAG); textPaint.setColor(textColor); textPaint.setTextSize(dp2px(14)); } //默认view的宽度 private int mDefaultWidth = dp2px(100); private int mDefaultHeight = mDefaultWidth; private int mDefaultPadding = dp2px(10); //绘制进度条的实际宽度 private int mMeasureHeight; private int mMeasureWidth; @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); //测量计算宽度 int widthSpecMode = MeasureSpec.getMode(widthMeasureSpec); int widthSpecSize = MeasureSpec.getSize(widthMeasureSpec); if (widthSpecMode == MeasureSpec.EXACTLY) { //当specMode = EXACTLY时，精确值模式，即当我们在布局文件中为View指定了具体的大小 mMeasureWidth = widthSpecSize; } else { //指定默认大小 mMeasureWidth = mDefaultWidth; if (widthSpecMode == MeasureSpec.AT_MOST) { mMeasureWidth = Math.min(mMeasureWidth, widthSpecSize); } } //测量计算View的高 int heightSpecMode = MeasureSpec.getMode(heightMeasureSpec); int heightSpecSize = MeasureSpec.getSize(heightMeasureSpec); if (heightSpecMode == MeasureSpec.EXACTLY) { //当specMode = EXACTLY时，精确值模式，即当我们在布局文件中为View指定了具体的大小 mMeasureHeight = heightSpecSize; } else { //指定默认大小 mMeasureHeight = mDefaultHeight; if (heightSpecMode == MeasureSpec.AT_MOST) { mMeasureHeight = Math.min(mMeasureHeight, heightSpecSize); } } mMeasureHeight = mMeasureHeight - getPaddingBottom() - getPaddingTop(); mMeasureWidth = mMeasureWidth - getPaddingLeft() - getPaddingBottom(); //重新测量 setMeasuredDimension(mMeasureWidth, mMeasureHeight); /** * 竖屏状态下 * 将view 的宽度平均分为6份，扫描区域距左右各1份，那么扫描区域的宽度占4份 * 将view 的调试平均分为4份，距离顶部1份，为保持与宽相等，bottom =mMeasureHeight/4+ width; */ int left =mMeasureWidth/6; int width = mMeasureWidth/6*4; int top = mMeasureHeight/4; int bottom =mMeasureHeight/4+ width; if (mMeasureHeight<mMeasureWidth){ top = mMeasureHeight/8; bottom =mMeasureHeight/8*6; left =(mMeasureWidth-(bottom-top))/2; width = (bottom-top); } frame = new Rect( left,top, left+width, bottom); } Rect frame; @Override protected void onDraw(Canvas canvas) { if (frame == null) { return; } int width = canvas.getWidth(); int height = canvas.getHeight(); // 除了中间的识别区域，其他区域都将蒙上一层半透明的图层 canvas.drawRect(0, 0, width, frame.top, maskPaint); canvas.drawRect(0, frame.top, frame.left, frame.bottom + 1, maskPaint); canvas.drawRect(frame.right + 1, frame.top, width, frame.bottom + 1, maskPaint); canvas.drawRect(0, frame.bottom + 1, width, height, maskPaint); String text = "将二维码放入框内，即可自动扫描"; canvas.drawText(text, (width - textPaint.measureText(text)) / 2, frame.bottom + textMarinTop, textPaint); // 四个角落的三角 Path leftTopPath = new Path(); leftTopPath.moveTo(frame.left + triAngleLength, frame.top + triAngleWidth / 2); leftTopPath.lineTo(frame.left + triAngleWidth / 2, frame.top + triAngleWidth / 2); leftTopPath.lineTo(frame.left + triAngleWidth / 2, frame.top + triAngleLength); canvas.drawPath(leftTopPath, traAnglePaint); Path rightTopPath = new Path(); rightTopPath.moveTo(frame.right - triAngleLength, frame.top + triAngleWidth / 2); rightTopPath.lineTo(frame.right - triAngleWidth / 2, frame.top + triAngleWidth / 2); rightTopPath.lineTo(frame.right - triAngleWidth / 2, frame.top + triAngleLength); canvas.drawPath(rightTopPath, traAnglePaint); Path leftBottomPath = new Path(); leftBottomPath.moveTo(frame.left + triAngleWidth / 2, frame.bottom - triAngleLength); leftBottomPath.lineTo(frame.left + triAngleWidth / 2, frame.bottom - triAngleWidth / 2); leftBottomPath.lineTo(frame.left + triAngleLength, frame.bottom - triAngleWidth / 2); canvas.drawPath(leftBottomPath, traAnglePaint); Path rightBottomPath = new Path(); rightBottomPath.moveTo(frame.right - triAngleLength, frame.bottom - triAngleWidth / 2); rightBottomPath.lineTo(frame.right - triAngleWidth / 2, frame.bottom - triAngleWidth / 2); rightBottomPath.lineTo(frame.right - triAngleWidth / 2, frame.bottom - triAngleLength); canvas.drawPath(rightBottomPath, traAnglePaint); //循环划线，从上到下 if (lineOffsetCount > frame.bottom - frame.top - dp2px(10)) { lineOffsetCount = 0; } else { lineOffsetCount = lineOffsetCount + 6; // canvas.drawLine(frame.left, frame.top + lineOffsetCount, frame.right, frame.top + lineOffsetCount, linePaint); //画一条红色的线 Rect lineRect = new Rect(); lineRect.left = frame.left; lineRect.top = frame.top + lineOffsetCount; lineRect.right = frame.right; lineRect.bottom = frame.top + dp2px(10) + lineOffsetCount; canvas.drawBitmap(((BitmapDrawable) (getResources().getDrawable(R.mipmap.scanline))).getBitmap(), null, lineRect, linePaint); } postInvalidateDelayed(10L, frame.left, frame.top, frame.right, frame.bottom); } private int dp2px(int dp) { float density = getContext().getResources().getDisplayMetrics().density; return (int) (dp * density + 0.5f); } }
早起的年轻人 认证博客专家 移动开发 项目管理 Java 只要用心去做，每一件事情还是有可能成功的，当然成功是没有界限的，只不过是达到自己心里的那个目标,公众号：我的大前端生涯，一个爱喝茶的程序员，通常会搞搞SpringBoot 、Herbinate、Mybatiys、Android、iOS、Flutter、Vue、小程序等.
