怎么在Android应用中实现一个图案解锁功能-创新互联

这期内容当中小编将会给大家带来有关怎么在Android应用中实现一个图案解锁功能，文章内容丰富且以专业的角度为大家分析和叙述，阅读完这篇文章希望大家可以有所收获。

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1.最关健的就是那个自定义九宫格View，代码来自framework下：LockPatternView，原生系统用的图片资源比较多，好像有7、8张吧，而且绘制的比较复杂，我找寻半天，眼睛都找瞎了，发现解压的QQ里面就3张图片，一个圈圈，两个点，没办法，只能修改代码了，在修改的过程中，才发现，其实可以把原生的LockPatternView给简化，绘制更少的图片，达到更好的效果。总共优化有：①去掉了连线的箭头，②原生的连线只有白色一种，改成根据不同状态显示黄色和红色两张色，③.原生view是先画点再画线，使得线覆盖在点的上面，影响美观，改成先画连线再画点。

关健部分代码onDraw函数：

@Override 
protected void onDraw(Canvas canvas) { 
 final ArrayList pattern = mPattern; 
 final int count = pattern.size(); 
 final boolean[][] drawLookup = mPatternDrawLookup; 
 
 if (mPatternDisplayMode == DisplayMode.Animate) { 
 
 // figure out which circles to draw 
 
 // + 1 so we pause on complete pattern 
 final int oneCycle = (count + 1) * MILLIS_PER_CIRCLE_ANIMATING; 
 final int spotInCycle = (int) (SystemClock.elapsedRealtime() - mAnimatingPeriodStart) 
 % oneCycle; 
 final int numCircles = spotInCycle / MILLIS_PER_CIRCLE_ANIMATING; 
 
 clearPatternDrawLookup(); 
 for (int i = 0; i < numCircles; i++) { 
 final Cell cell = pattern.get(i); 
 drawLookup[cell.getRow()][cell.getColumn()] = true; 
 } 
 
 // figure out in progress portion of ghosting line 
 
 final boolean needToUpdateInProgressPoint = numCircles > 0 
 && numCircles < count; 
 
 if (needToUpdateInProgressPoint) { 
 final float percentageOfNextCircle = ((float) (spotInCycle % MILLIS_PER_CIRCLE_ANIMATING)) 
  / MILLIS_PER_CIRCLE_ANIMATING; 
 
 final Cell currentCell = pattern.get(numCircles - 1); 
 final float centerX = getCenterXForColumn(currentCell.column); 
 final float centerY = getCenterYForRow(currentCell.row); 
 
 final Cell nextCell = pattern.get(numCircles); 
 final float dx = percentageOfNextCircle 
  * (getCenterXForColumn(nextCell.column) - centerX); 
 final float dy = percentageOfNextCircle 
  * (getCenterYForRow(nextCell.row) - centerY); 
 mInProgressX = centerX + dx; 
 mInProgressY = centerY + dy; 
 } 
 // TODO: Infinite loop here... 
 invalidate(); 
 } 
 
 final float squareWidth = mSquareWidth; 
 final float squareHeight = mSquareHeight; 
 
 float radius = (squareWidth * mDiameterFactor * 0.5f); 
 mPathPaint.setStrokeWidth(radius); 
 
 final Path currentPath = mCurrentPath; 
 currentPath.rewind(); 
 
 // TODO: the path should be created and cached every time we hit-detect 
 // a cell 
 // only the last segment of the path should be computed here 
 // draw the path of the pattern (unless the user is in progress, and 
 // we are in stealth mode) 
 final boolean drawPath = (!mInStealthMode || mPatternDisplayMode == DisplayMode.Wrong); 
 
 // draw the arrows associated with the path (unless the user is in 
 // progress, and 
 // we are in stealth mode) 
 boolean oldFlag = (mPaint.getFlags() & Paint.FILTER_BITMAP_FLAG) != 0; 
 mPaint.setFilterBitmap(true); // draw with higher quality since we 
   // render with transforms 
 // draw the lines 
 if (drawPath) { 
 boolean anyCircles = false; 
 for (int i = 0; i < count; i++) { 
 Cell cell = pattern.get(i); 
 
 // only draw the part of the pattern stored in 
 // the lookup table (this is only different in the case 
 // of animation). 
 if (!drawLookup[cell.row][cell.column]) { 
 break; 
 } 
 anyCircles = true; 
 
 float centerX = getCenterXForColumn(cell.column); 
 float centerY = getCenterYForRow(cell.row); 
 if (i == 0) { 
 currentPath.moveTo(centerX, centerY); 
 } else { 
 currentPath.lineTo(centerX, centerY); 
 } 
 } 
 
 // add last in progress section 
 if ((mPatternInProgress || mPatternDisplayMode == DisplayMode.Animate) 
 && anyCircles) { 
 currentPath.lineTo(mInProgressX, mInProgressY); 
 } 
 // chang the line color in different DisplayMode 
 if (mPatternDisplayMode == DisplayMode.Wrong) 
 mPathPaint.setColor(Color.RED); 
 else 
 mPathPaint.setColor(Color.YELLOW); 
 canvas.drawPath(currentPath, mPathPaint); 
 } 
 
 // draw the circles 
 final int paddingTop = getPaddingTop(); 
 final int paddingLeft = getPaddingLeft(); 
 
 for (int i = 0; i < 3; i++) { 
 float topY = paddingTop + i * squareHeight; 
 // float centerY = mPaddingTop + i * mSquareHeight + (mSquareHeight 
 // / 2); 
 for (int j = 0; j < 3; j++) { 
 float leftX = paddingLeft + j * squareWidth; 
 drawCircle(canvas, (int) leftX, (int) topY, drawLookup[i][j]); 
 } 
 } 
 
 mPaint.setFilterBitmap(oldFlag); // restore default flag 
} 

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