为了这个可以拖拽的扫描框,着实头痛了几天
主要借鉴文章:http://blog.youkuaiyun.com/farble/article/details/44235555
public final class ViewfinderView extends View {
private static final String TAG = “log”;
/**
* 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;
/**
* 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;
/**
* 将扫描的二维码拍下来,这里没有这个功能,暂时不考虑
*/
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;
//TODO start
private onLocationListener locationListener;/*listen to the Rect */
private onChangeLocationlistener changeLocationlistener;/*listening position changed */
private int MODE;
private static final int MODE_OUTSIDE = 0x000000aa;/*170*/
private static final int MODE_INSIDE = 0x000000bb;/*187*/
private static final int MODE_POINT = 0X000000cc;/*204*/
private static final int MODE_ILLEGAL = 0X000000dd;/*221*/
private static final int minWidth = 100;/*the minimum width of the rectangle*/
private static final int minHeight = 200;/*the minimum height of the rectangle*/
private static final int START_X = 200;
private static final int START_Y = 200;
private static final float EDGE_WIDTH = 1.8f;
private static final int ACCURACY = 15;/*touch accuracy*/
private int pointPosition;/*vertex of a rectangle*/
private int sX;/*start X location*/
private int sY;/*start Y location*/
private int eX;/*end X location*/
private int eY;/*end Y location*/
private int pressX;/*X coordinate values while finger press*/
private int pressY;/*Y coordinate values while finger press*/
private int memonyX;/*the last time the coordinate values of X*/
private int memonyY;/*the last time the coordinate values of Y*/
private int coverWidth = 600;/*width of selection box*/
private int coverHeight = 720;/*height of selection box*/
private Paint mPaint;
private Paint mPaintLine;
private Bitmap mBitmapCover;
private Bitmap mBitmapRectBlack;
private PorterDuffXfermode xfermode;/*paint mode*/
//TODO end
public ViewfinderView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
density = context.getResources().getDisplayMetrics().density;
//将像素转换成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<ResultPoint>(5);
}
@SuppressWarnings("deprecation")
private void init() {
/* sX = START_X;
sY = START_Y;*/
WindowManager manager = (WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE);
int width = manager.getDefaultDisplay().getWidth();
int height = manager.getDefaultDisplay().getHeight();
mBitmapCover = makeBitmap(width, height, 0x5A000000, 0, 0);
mBitmapRectBlack = makeBitmap(coverWidth, coverHeight, 0xff000000, coverWidth, coverHeight);
sX = width / 2 - coverWidth / 2;
sY = height / 2 - coverHeight / 2;
eX = sX + coverWidth;
eY = sY + coverHeight;
pressX = 0;
pressY = 0;
xfermode = new PorterDuffXfermode(PorterDuff.Mode.SRC_IN);
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaintLine = new Paint();
mPaintLine.setColor(Color.WHITE);
mPaintLine.setStrokeWidth(2.0f);
}
/*生成bitmap*/
private Bitmap makeBitmap(int mwidth, int mheight, int resource, int staX, int staY) {
Bitmap bm = Bitmap.createBitmap(mwidth, mheight, Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(bm);
Paint p = new Paint(Paint.ANTI_ALIAS_FLAG);
p.setColor(resource);
c.drawRect(staX, staY, mwidth, mheight, p);
return bm;
}
@Override
public boolean dispatchTouchEvent(MotionEvent event) {
//请求父控件不拦截触摸事件
getParent().requestDisallowInterceptTouchEvent(true);
return super.dispatchTouchEvent(event);
}
@SuppressWarnings("NullableProblems")
@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
if (changeLocationlistener != null) {
changeLocationlistener.locationChange("change self");
} else {
changeLocationlistener = null;
}
memonyX = (int) event.getX();
memonyY = (int) event.getY();
checkMode(memonyX, memonyY);
break;
case MotionEvent.ACTION_MOVE: {
switch (MODE) {
case MODE_ILLEGAL:
pressX = (int) event.getX();
pressY = (int) event.getY();
recoverFromIllegal(pressX, pressY);
postInvalidate();
break;
case MODE_OUTSIDE:
//do nothing;
break;
case MODE_INSIDE:
pressX = (int) event.getX();
pressY = (int) event.getY();
moveByTouch(pressX, pressY);
postInvalidate();
break;
default:
/*MODE_POINT*/
pressX = (int) event.getX();
pressY = (int) event.getY();
mPaintLine.setColor(getContext().getResources().getColor(R.color.white));
moveByPoint(pressX, pressY);
postInvalidate();
break;
}
}
break;
case MotionEvent.ACTION_UP:
mPaintLine.setColor(Color.WHITE);
postInvalidate();
break;
default:
break;
}
return true;
}
/*从非法状态恢复,这里处理的是达到最小值后能拉伸放大*/
private void recoverFromIllegal(int rx, int ry) {
if ((rx > sX && ry > sY) && (rx < eX && ry < eY)) {
MODE = MODE_ILLEGAL;
} else {
MODE = MODE_POINT;
}
}
private void checkMode(int cx, int cy) {
if (cx > sX && cx < eX && cy > sY && cy < eY) {
MODE = MODE_INSIDE;
} else if (nearbyPoint(cx, cy) < 4) {
MODE = MODE_POINT;
} else {
MODE = MODE_OUTSIDE;
}
}
/*判断点(inX,inY)是否靠近矩形的4个顶点*/
private int nearbyPoint(int inX, int inY) {
if ((Math.abs(sX - inX) <= ACCURACY && (Math.abs(inY - sY) <= ACCURACY))) {/*left-up angle*/
pointPosition = 0;
return 0;
}
if ((Math.abs(eX - inX) <= ACCURACY && (Math.abs(inY - sY) <= ACCURACY))) {/*right-up angle*/
pointPosition = 1;
return 1;
}
if ((Math.abs(sX - inX) <= ACCURACY && (Math.abs(inY - eY) <= ACCURACY))) {/*left-down angle*/
pointPosition = 2;
return 2;
}
if ((Math.abs(eX - inX) <= ACCURACY && (Math.abs(inY - eY) <= ACCURACY))) {/*right-down angle*/
pointPosition = 3;
return 3;
}
pointPosition = 100;
return 100;
}
/*刷新矩形的坐标*/
private void refreshLocation(int isx, int isy, int iex, int iey) {
this.sX = isx;
this.sY = isy;
this.eX = iex;
this.eY = iey;
}
/*矩形随手指移动*/
private void moveByTouch(int mx, int my) {/*move center point*/
int dX = mx - memonyX;
int dY = my - memonyY;
sX += dX;
sY += dY;
eX = sX + coverWidth;
eY = sY + coverHeight;
memonyX = mx;
memonyY = my;
}
/*检测矩形是否达到最小值*/
private boolean checkLegalRect(int cHeight, int cWidth) {
return (cHeight > minHeight && cWidth > minWidth);
}
/*点击顶点附近时的缩放处理*/
@SuppressWarnings("SuspiciousNameCombination")
private void moveByPoint(int bx, int by) {
switch (pointPosition) {
case 0:/*left-up*/
coverWidth = Math.abs(eX - bx);
coverHeight = Math.abs(eY - by);
//noinspection SuspiciousNameCombination
if (!checkLegalRect(coverWidth, coverHeight)) {
MODE = MODE_ILLEGAL;
} else {
mBitmapRectBlack = null;
mBitmapRectBlack = makeBitmap(coverWidth, coverHeight, 0xff000000, coverWidth, coverHeight);
refreshLocation(bx, by, eX, eY);
}
break;
case 1:/*right-up*/
coverWidth = Math.abs(bx - sX);
coverHeight = Math.abs(eY - by);
if (!checkLegalRect(coverWidth, coverHeight)) {
MODE = MODE_ILLEGAL;
} else {
mBitmapRectBlack = null;
mBitmapRectBlack = makeBitmap(coverWidth, coverHeight, 0xff000000, coverWidth, coverHeight);
refreshLocation(sX, by, bx, eY);
}
break;
case 2:/*left-down*/
coverWidth = Math.abs(eX - bx);
coverHeight = Math.abs(by - sY);
if (!checkLegalRect(coverWidth, coverHeight)) {
MODE = MODE_ILLEGAL;
} else {
mBitmapRectBlack = null;
mBitmapRectBlack = makeBitmap(coverWidth, coverHeight, 0xff000000, coverWidth, coverHeight);
refreshLocation(bx, sY, eX, by);
}
break;
case 3:/*right-down*/
coverWidth = Math.abs(bx - sX);
coverHeight = Math.abs(by - sY);
if (!checkLegalRect(coverWidth, coverHeight)) {
MODE = MODE_ILLEGAL;
} else {
mBitmapRectBlack = null;
mBitmapRectBlack = makeBitmap(coverWidth, coverHeight, 0xff000000, coverWidth, coverHeight);
refreshLocation(sX, sY, bx, by);
}
break;
default:
break;
}
}
public void setLocationListener(onLocationListener locationListener) {
this.locationListener = locationListener;
}
public interface onLocationListener {
public void locationRect(int startX, int startY, int endX, int endY);
}
public interface onChangeLocationlistener {
@SuppressWarnings("SameParameterValue")
public void locationChange(String msg);
}
@Override
public void onDraw(Canvas canvas) {
super.onDraw(canvas);
//获取屏幕的宽和高
int screenWidth = canvas.getWidth();
int screenHeight = canvas.getHeight();
mPaint.setFilterBitmap(false);
int sc = canvas.saveLayer(0, 0, canvas.getWidth(), canvas.getHeight(), null,
Canvas.MATRIX_SAVE_FLAG |
Canvas.CLIP_SAVE_FLAG |
Canvas.HAS_ALPHA_LAYER_SAVE_FLAG |
Canvas.FULL_COLOR_LAYER_SAVE_FLAG |
Canvas.CLIP_TO_LAYER_SAVE_FLAG);
canvas.drawBitmap(mBitmapCover, 0, 0, mPaint);
mPaint.setXfermode(xfermode);
canvas.drawBitmap(mBitmapRectBlack, sX, sY, mPaint);
if (locationListener != null) {
locationListener.locationRect(sX, sY, eX, eY);
}
mPaint.setXfermode(null);
canvas.restoreToCount(sc);
//canvas.drawLine((float) sX - EDGE_WIDTH, (float) sY - EDGE_WIDTH, (float) eX + EDGE_WIDTH, (float) sY - EDGE_WIDTH, mPaintLine);/*up -*/
//canvas.drawLine((float) sX - EDGE_WIDTH, (float) eY + EDGE_WIDTH, (float) eX + EDGE_WIDTH, (float) eY + EDGE_WIDTH, mPaintLine);/*down -*/
//canvas.drawLine((float) sX - EDGE_WIDTH, (float) sY - EDGE_WIDTH, (float) sX - EDGE_WIDTH, (float) eY + EDGE_WIDTH, mPaintLine);/*left |*/
//canvas.drawLine((float) eX + EDGE_WIDTH, (float) sY - EDGE_WIDTH, (float) eX + EDGE_WIDTH, (float) eY + EDGE_WIDTH, mPaintLine);/*righ |*/
//TODO 画出八个角
float left = sX - EDGE_WIDTH;
float top = sY - EDGE_WIDTH;
float right = eX + EDGE_WIDTH;
float bottom = eY + EDGE_WIDTH;
/* //如果矩形框 已经超出屏幕 不再继续移动
if (sX <= 0 || eX >= screenWidth || sY <= 0 || eY >= screenHeight) {
return ;
}*/
if (!isFirst) {
isFirst = true;
slideTop = (int) top;
slideBottom = (int) bottom;
}
Paint paint = new Paint();
paint.setColor(Color.GREEN);
//1 左上
canvas.drawRect(left, top, left + ScreenRate,
top + CORNER_WIDTH, paint);
canvas.drawRect(left, top, left + CORNER_WIDTH, top
+ ScreenRate, paint);
//2 右上
canvas.drawRect(right - ScreenRate, top, right,
top + CORNER_WIDTH, paint);
canvas.drawRect(right - CORNER_WIDTH, top, right, top
+ ScreenRate, paint);
//3 左下
canvas.drawRect(left, bottom - CORNER_WIDTH, left
+ ScreenRate, bottom, paint);
canvas.drawRect(left, bottom - ScreenRate,
left + CORNER_WIDTH, bottom, paint);
//4 右下
canvas.drawRect(right - ScreenRate, bottom - CORNER_WIDTH,
right, bottom, paint);
canvas.drawRect(right - CORNER_WIDTH, bottom - ScreenRate,
right, 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 >= bottom) {
slideTop = (int) top;
}
canvas.drawRect(left + MIDDLE_LINE_PADDING, slideTop - MIDDLE_LINE_WIDTH / 2, 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(getResources().getString(R.string.scan_text), left + 30, (float) (bottom + (float) TEXT_PADDING_TOP * density), paint);
paint.setColor(getResources().getColor(R.color.b_commit));
canvas.drawText(getResources().getString(R.string.scan_notice), left, (float) (bottom + (float) TEXT_PADDING_TOP * density + 50), 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(left + point.getX(), top
+ point.getY(), 6.0f, paint);
}
}
if (currentLast != null) {
paint.setAlpha(OPAQUE / 2);
paint.setColor(resultPointColor);
for (ResultPoint point : currentLast) {
canvas.drawCircle(left + point.getX(), 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, (int) left, (int) top,
(int) right, (int) bottom);
}
public void drawViewfinder() {
resultBitmap = null;
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) {
possibleResultPoints.add(point);
}
}