Android 二维码框4个角&上下滚动条&闪光灯

二维码框4个角&上下滚动条&闪光灯

本文章是在一个大牛的demo上修改的，感谢大牛分享，zxing关键代码都是一样，只在标题上说的三个功能讲解

 

成员属性如下，方便下面讲解：

/**
	 * 四个绿色边角对应的长度
	 */
	private int ScreenRate;

	/**
	 * 四个绿色边角对应的宽度
	 */
	private static final int CORNER_WIDTH = 5;
	/**
	 * 扫描框中的中间线的宽度
	 */
	private static final int MIDDLE_LINE_WIDTH = 6;

	/**
	 * 扫描框中的中间线的与扫描框左右的间隙
	 */
	private static final int MIDDLE_LINE_PADDING = 5;

	/**
	 * 中间那条线每次刷新移动的距离
	 */
	private static final int SPEEN_DISTANCE = 5;

	/**
	 * 手机的屏幕密度
	 */
	private static float density;
	/**
	 * 字体大小
	 */
	private static final int TEXT_SIZE = 16;
	/**
	 * 字体距离扫描框下面的距离
	 */
	private static final int TEXT_PADDING_TOP = 30;
	boolean isFirst;
	/**
	 * 中间滑动线的最顶端位置
	 */
	private int slideTop;

	/**
	 * 中间滑动线的最底端位置
	 */
	private int slideBottom;

 

ViewfinderView方法中进行初始化操作，涉及的代码如下：

		density = context.getResources().getDisplayMetrics().density;
		// 将像素转换成dp
		ScreenRate = (int) (15 * density)

(一) 二维码框4个角&上下滚动条

         边框顾名思义也就是onDraw()方法画边，使用画笔的缺点是只能为两点画线，在四个角 ，画4个独立的直角

4个直角各两条线，所以得画8条线

         上下滚动条，用画笔加载一张横线的图片就可以 这个不难理解

在onDraw()代码如下：

	@Override
	public void onDraw(Canvas canvas) {
		// 中间的扫描框，你要修改扫描框的大小，去CameraManager里面修改
		Rect frame = CameraManager.get().getFramingRect();
		if (frame == null) {
			return;
		}
		// 初始化中间线滑动的最上边和最下边
		if (!isFirst) {
			isFirst = true;
			slideTop = frame.top;
			slideBottom = frame.bottom;
		}

		// 获取屏幕的宽和高
		int width = canvas.getWidth();
		int height = canvas.getHeight();

		// 画出扫描框外面的阴影部分，共四个部分，扫描框的上面到屏幕上面，扫描框的下面到屏幕下面
		// 扫描框的左边面到屏幕左边，扫描框的右边到屏幕右边
		// Draw the exterior (i.e. outside the framing rect) darkened
		paint.setColor(resultBitmap != null ? resultColor : maskColor);
		canvas.drawRect(0, 0, width, frame.top, paint);
		canvas.drawRect(0, frame.top, frame.left, frame.bottom + 1, paint);
		canvas.drawRect(frame.right + 1, frame.top, width, frame.bottom + 1,
				paint);
		canvas.drawRect(0, frame.bottom + 1, width, height, paint);

		if (resultBitmap != null) {
			// Draw the opaque result bitmap over the scanning rectangle
			paint.setAlpha(OPAQUE);
			canvas.drawBitmap(resultBitmap, frame.left, frame.top, paint);
		} else {
			// 画扫描框边上的角，总共8个部分
			paint.setColor(Color.GREEN);
			canvas.drawRect(frame.left, frame.top, frame.left + ScreenRate,
					frame.top + CORNER_WIDTH, paint);
			canvas.drawRect(frame.left, frame.top, frame.left + CORNER_WIDTH, frame.top
					+ ScreenRate, paint);
			canvas.drawRect(frame.right - ScreenRate, frame.top, frame.right,
					frame.top + CORNER_WIDTH, paint);
			canvas.drawRect(frame.right - CORNER_WIDTH, frame.top, frame.right, frame.top
					+ ScreenRate, paint);
			canvas.drawRect(frame.left, frame.bottom - CORNER_WIDTH, frame.left
					+ ScreenRate, frame.bottom, paint);
			canvas.drawRect(frame.left, frame.bottom - ScreenRate,
					frame.left + CORNER_WIDTH, frame.bottom, paint);
			canvas.drawRect(frame.right - ScreenRate, frame.bottom - CORNER_WIDTH,
					frame.right, frame.bottom, paint);
			canvas.drawRect(frame.right - CORNER_WIDTH, frame.bottom - ScreenRate,
					frame.right, frame.bottom, paint);
			
			//绘制中间的线,每次刷新界面，中间的线往下移动SPEEN_DISTANCE
			
			slideTop += SPEEN_DISTANCE;
			if(slideTop >= frame.bottom){
				slideTop = frame.top;
			}
			Rect lineRect = new Rect();  
            lineRect.left = frame.left;  
            lineRect.right = frame.right;  
            lineRect.top = slideTop;  
            lineRect.bottom = slideTop + 18;  
            canvas.drawBitmap(((BitmapDrawable)(getResources().getDrawable(R.drawable.qrcode_scan_line))).getBitmap(), null, lineRect, paint); 
			
        	//画扫描框下面的字
            paint.setColor(Color.WHITE);    
            paint.setTextSize(TEXT_SIZE * density);    
            paint.setAlpha(0x40);    
            paint.setTypeface(Typeface.create("System", Typeface.BOLD));   
            String text = "将二维码放入框内, 即可自动扫描";  
            float textWidth = paint.measureText(text);  
              
            canvas.drawText(text, (width - textWidth)/2, (float) (frame.bottom + (float)TEXT_PADDING_TOP *density), paint); 
			
			

			Collection currentPossible = possibleResultPoints;
			Collection currentLast = lastPossibleResultPoints;
			if (currentPossible.isEmpty()) {
				lastPossibleResultPoints = null;
			} else {
				possibleResultPoints = new HashSet(5);
				lastPossibleResultPoints = currentPossible;
				paint.setAlpha(OPAQUE);
				paint.setColor(resultPointColor);
				for (ResultPoint point : currentPossible) {
					canvas.drawCircle(frame.left + point.getX(), frame.top
							+ point.getY(), 6.0f, paint);
				}
			}
			if (currentLast != null) {
				paint.setAlpha(OPAQUE / 2);
				paint.setColor(resultPointColor);
				for (ResultPoint point : currentLast) {
					canvas.drawCircle(frame.left + point.getX(), frame.top
							+ point.getY(), 3.0f, paint);
				}
			}

			
			//只刷新扫描框的内容，其他地方不刷新
			postInvalidateDelayed(ANIMATION_DELAY, frame.left, frame.top,
					frame.right, frame.bottom);
			
		}
	}

(二)闪光灯

         首先在carmra布局中加一个按钮或者图片按钮

       

注意的一点是系统中只能存在一个Camera对象 ，所以在CameraManager中加一个获取Camera对象的方法

  

  public static Camera getCamera(){
	  return camera;
  }

声明一个Camera属性

初始化：

CameraManager.get().openDriver(surfaceHolder);
			camera = CameraManager.getCamera();

 

在操作扫描二维码的activity中设置按钮的监听事件

		//开闭闪光灯事件  
		lightButton.setOnClickListener(new OnClickListener() {

			@Override
			public void onClick(View arg0) {
				if (lightButton.getText().toString().equals("打开闪光灯")) {
					parameter = camera.getParameters();
					parameter.setFlashMode(Parameters.FLASH_MODE_TORCH);
					camera.setParameters(parameter);
					lightButton.setText("关闭闪光灯");
				} else if (lightButton.getText().toString().equals("关闭闪光灯")) {
					parameter = camera.getParameters();
					parameter.setFlashMode(Parameters.FLASH_MODE_OFF);
					camera.setParameters(parameter);
					lightButton.setText("打开闪光灯");
				}
			}
		});