Java tutorial
/* * Copyright (C) 2008 ZXing authors * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package me.test.zxing; import android.annotation.SuppressLint; import android.content.Context; import android.content.res.Resources; import android.graphics.Bitmap; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.Rect; import android.support.v4.content.ContextCompat; import android.util.AttributeSet; import android.view.View; import com.google.zxing.ResultPoint; import java.util.ArrayList; import java.util.List; import me.test.zxing.camera.CameraManager; /** * This view is overlaid on top of the camera preview. It adds the viewfinder rectangle and partial * transparency outside it, as well as the laser scanner animation and result points. * * @author dswitkin@google.com (Daniel Switkin) */ public final class ViewfinderView extends View { private static final int[] SCANNER_ALPHA = { 0, 64, 128, 192, 255, 192, 128, 64 }; private static final long ANIMATION_DELAY = 80L; private static final int CURRENT_POINT_OPACITY = 0xA0; private static final int MAX_RESULT_POINTS = 20; private static final int POINT_SIZE = 6; private CameraManager cameraManager; private final Paint paint; private Bitmap resultBitmap; private final int maskColor; private final int resultColor; private final int laserColor; private final int resultPointColor; private int scannerAlpha; private List<ResultPoint> possibleResultPoints; private List<ResultPoint> lastPossibleResultPoints; private boolean isFirst; /** * ? */ private int slideTop; // This constructor is used when the class is built from an XML resource. public ViewfinderView(Context context, AttributeSet attrs) { super(context, attrs); // Initialize these once for performance rather than calling them every time in onDraw(). paint = new Paint(Paint.ANTI_ALIAS_FLAG); Resources resources = getResources(); maskColor = resources.getColor(R.color.viewfinder_mask); resultColor = resources.getColor(R.color.result_view); // laserColor = resources.getColor(R.color.viewfinder_laser); laserColor = ContextCompat.getColor(getContext(), android.R.color.holo_green_dark); resultPointColor = resources.getColor(R.color.possible_result_points); scannerAlpha = 0; possibleResultPoints = new ArrayList<>(5); lastPossibleResultPoints = null; } public void setCameraManager(CameraManager cameraManager) { this.cameraManager = cameraManager; } @SuppressLint("DrawAllocation") @Override public void onDraw(Canvas canvas) { if (cameraManager == null) { return; // not ready yet, early draw before done configuring } Rect frame = cameraManager.getFramingRect(); Rect previewFrame = cameraManager.getFramingRectInPreview(); if (frame == null || previewFrame == null) { return; } int width = canvas.getWidth(); int height = canvas.getHeight(); if (!isFirst) { isFirst = true; slideTop = frame.top; } // // 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(CURRENT_POINT_OPACITY); canvas.drawBitmap(resultBitmap, null, frame, paint); } else { // paint.setColor(ContextCompat.getColor(getContext(), android.R.color.holo_green_dark)); // canvas.drawRect(frame.left, frame.top, frame.left + 50, frame.top + 10, paint); canvas.drawRect(frame.left, frame.top, frame.left + 10, frame.top + 50, paint); //? canvas.drawRect(frame.right - 50, frame.top, frame.right, frame.top + 10, paint); canvas.drawRect(frame.right - 10, frame.top, frame.right, frame.top + 50, paint); // canvas.drawRect(frame.left, frame.bottom - 10, frame.left + 50, frame.bottom, paint); canvas.drawRect(frame.left, frame.bottom - 50, frame.left + 10, frame.bottom, paint); //? canvas.drawRect(frame.right - 50, frame.bottom - 10, frame.right, frame.bottom, paint); canvas.drawRect(frame.right - 10, frame.bottom - 50, frame.right, frame.bottom, paint); //,??SPEEN_DISTANCE slideTop += 5; if (slideTop >= frame.bottom) { slideTop = frame.top; } canvas.drawRect(frame.left + 5, slideTop - 6 / 2, frame.right - 5, slideTop + 6 / 2, paint); float scaleX = frame.width() / (float) previewFrame.width(); float scaleY = frame.height() / (float) previewFrame.height(); List<ResultPoint> currentPossible = possibleResultPoints; List<ResultPoint> currentLast = lastPossibleResultPoints; int frameLeft = frame.left; int frameTop = frame.top; if (currentPossible.isEmpty()) { lastPossibleResultPoints = null; } else { possibleResultPoints = new ArrayList<>(5); lastPossibleResultPoints = currentPossible; paint.setAlpha(CURRENT_POINT_OPACITY); paint.setColor(resultPointColor); synchronized (currentPossible) { for (ResultPoint point : currentPossible) { canvas.drawCircle(frameLeft + (int) (point.getX() * scaleX), frameTop + (int) (point.getY() * scaleY), POINT_SIZE, paint); } } } if (currentLast != null) { paint.setAlpha(CURRENT_POINT_OPACITY / 2); paint.setColor(resultPointColor); synchronized (currentLast) { float radius = POINT_SIZE / 2.0f; for (ResultPoint point : currentLast) { canvas.drawCircle(frameLeft + (int) (point.getX() * scaleX), frameTop + (int) (point.getY() * scaleY), radius, paint); } } } // Request another update at the animation interval, but only repaint the laser line, // not the entire viewfinder mask. postInvalidateDelayed(ANIMATION_DELAY, frame.left - POINT_SIZE, frame.top - POINT_SIZE, frame.right + POINT_SIZE, frame.bottom + POINT_SIZE); } } public void drawViewfinder() { Bitmap resultBitmap = this.resultBitmap; this.resultBitmap = null; if (resultBitmap != null) { resultBitmap.recycle(); } invalidate(); } /** * Draw a bitmap with the result points highlighted instead of the live scanning display. * * @param barcode An image of the decoded barcode. */ public void drawResultBitmap(Bitmap barcode) { resultBitmap = barcode; invalidate(); } public void addPossibleResultPoint(ResultPoint point) { List<ResultPoint> points = possibleResultPoints; synchronized (points) { points.add(point); int size = points.size(); if (size > MAX_RESULT_POINTS) { // trim it points.subList(0, size - MAX_RESULT_POINTS / 2).clear(); } } } }