package com.google.zxing.client.android;
import com.google.zxing.ResultPoint;
import com.google.zxing.client.android.camera.CameraManager;
import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.Typeface;
import android.util.AttributeSet;
import android.view.View;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
/**
* 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 {
//维护cameraManager变量
private CameraManager cameraManager;
//刷新界面的时间
private static final long ANIMATION_DELAY = 10L ;
private static final int OPAQUE = 0xFF ;
//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 = 10 ;
//扫描框中中间线的宽度
private static final int MiDDLE_LINE_WIDTH = 6 ;
//扫描框中的中间线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;
//画笔对象的引用
private Paint paint ;
//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 ;
private Bitmap resultBitmap ;
private final int maskColor ;
private final int resultColor ;
private final int resultPointColor ;
private Collection<ResultPoint> possibleResultPoints ;
private Collection<ResultPoint> lastPossibleResultPoints ;
boolean isFirst ;
public ViewfinderView( Context context , AttributeSet attrs ){
super(context , attrs);
density = context.getResources().getDisplayMetrics().density;
//像素转化成dp
ScreenRate = ( int) ( 20*density);
paint = new Paint();
Resources resources = getResources();
maskColor = resources.getColor(R.color.viewfinder_mask);
resultColor = resources.getColor(R.color.result_view);
resultPointColor = resources.getColor(R.color.possible_result_points);
possibleResultPoints = new HashSet<>( 5);
}
//初始化cameraManager对象
public void setCameraManager(CameraManager cameraManager) {
this.cameraManager = cameraManager;
}
@Override
protected void onDraw(Canvas canvas) {
//中间的扫描框,想要修改扫描框的大小可以去CameraManager里面修改
Rect frame = cameraManager.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() ;
paint.setColor(resultBitmap != null ? resultColor : maskColor );
//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
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;
}
canvas.drawRect(frame.left + MIDDLE_LINE_PADDING, slideTop - MiDDLE_LINE_WIDTH/ 2, frame.right - MIDDLE_LINE_PADDING,slideTop + MiDDLE_LINE_WIDTH/ 2, 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));
canvas.drawText( "请将二维码对准屏幕正中央扫描框", frame.left, ( float) (frame.bottom + ( float)TEXT_PADDING_TOP *density), paint);
Collection<ResultPoint> currentPossible = possibleResultPoints;
Collection<ResultPoint> currentLast = lastPossibleResultPoints;
if (currentPossible.isEmpty()) {
lastPossibleResultPoints = null;
} else {
possibleResultPoints = new HashSet<ResultPoint>( 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);
}
}
public void drawViewfinder() {
resultBitmap = null;
invalidate();
}
public void drawResultBitmap(Bitmap barcode) {
resultBitmap = barcode;
invalidate();
}
public void addPossibleResultPoint(ResultPoint point) {
possibleResultPoints.add(point);
}
} |
Java技术网站 → 『 Java开发技术 』 → 『 Android技术专题 』 → android 自定义view 实现定制二维码扫描框
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