我正在为 iPad 编写一个小型单词搜索游戏。我有一个UIViewController，我将字母随机平铺在UIView( lettersView) 中。我将标签的标签设置在一个 10x10 大小的矩阵中，UILabel每个字母使用一个。
这是我的问题：我不知道如何绘制字母（UILabels）。我已经研究过这个问题并且很困惑使用哪种方式（触摸，opengl，石英，hittest）。
- 我只想从第一个点到最后一个点画一条直线（向下触摸）。
- 当用户点击 时
lettersView，我必须找到被点击的字母。如果我得到UILabel最先点击的那封信，我可以找到这封信。 - 当用户移动他们的手指时，它应该画线，但是当用户移动它时，它必须删除旧的。
- 当用户触摸时，我怎样才能得到最后一个
UILabel？如果我得到第一个和最后一个 uilabel，我可以检查它是否可绘制。
（我发现了一个以 ARC 模式编写的小型绘图示例。但我无法将其转换为非 ARC。）
你说的我都做了。但我有一些问题。它在 drawRect 方法上画线。当我画第二行时，它会删除旧的。这是代码：
-(void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
touchStart = [[touches anyObject] locationInView:self];
float xPos=touchStart.x;
float yPos=touchStart.y;
startIndexCol = floor(xPos / letterWidth);
startIndexRow = floor(yPos / letterHeight);
xPos = (startIndexCol * letterWidth) + letterWidth/2;
yPos = (startIndexRow * letterHeight) + letterHeight/2;
touchStart = CGPointMake(xPos, yPos);
touchCurrent = touchStart;
[self setNeedsDisplay];
}
-(void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
touchCurrent = [[touches anyObject] locationInView:self];
//CGRect frame = CGRectMake(touchStart.x, touchStart.y, touchCurrent.x, touchCurrent.y);
//[self setNeedsDisplayInRect:frame];
[self setNeedsDisplay];
}
-(void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
touchCurrent = [[touches anyObject] locationInView:self];
//[self hitTest:touchCurrent withEvent:event];
float xPos=touchCurrent.x;
float yPos=touchCurrent.y;
endIndexCol = floor(xPos / letterWidth);
endIndexRow = floor(yPos / letterHeight);
xPos = (endIndexCol * letterWidth) + letterWidth/2;
yPos = (endIndexRow * letterHeight) + letterHeight/2;
touchCurrent = CGPointMake(xPos, yPos);
//CGRect frame = CGRectMake(touchStart.x, touchStart.y, touchCurrent.x, touchCurrent.y);
//[self setNeedsDisplayInRect:frame];
//check if it can be drawn
if ((startIndexCol == endIndexCol) && (startIndexRow == endIndexRow)) {
//clear, do nothing
touchStart = touchCurrent = (CGPoint) { -1, -1 };
startIndexCol = startIndexRow = endIndexCol = endIndexRow = -1;
}
else{
if (startIndexRow == endIndexRow) {//horizontal
if (endIndexCol > startIndexCol) {
[delegate checkWordInHorizontal:startIndexRow start:startIndexCol end:endIndexCol];
}
else{
[delegate checkWordInHorizontalBack:startIndexRow start:startIndexCol end:endIndexCol];
}
}
else if (startIndexCol == endIndexCol){ //vertical
if (endIndexRow > startIndexRow) {
[delegate checkWordInVertical:startIndexCol start:startIndexRow end:endIndexRow];
}
else{
[delegate checkWordInVerticalBack:startIndexCol start:startIndexRow end:endIndexRow];
}
}
}
[self setNeedsDisplay];
}
-(UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event{
UIView *subview = [super hitTest:point withEvent:event];
if ([subview isEqual:self]) {
NSLog(@"point:%f - %f", point.x, point.y);
return self;
}
return nil;
}
-(void)drawLine{
NSLog(@"draw it");
drawIt=YES;
[self setNeedsDisplay];
}
- (void)drawRect:(CGRect)rect
{
[super drawRect:rect];
if (drawIt) {
NSLog(@"drawit");
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGContextSetLineWidth(ctx, 20.0);
CGContextSetRGBStrokeColor(ctx, 1.0, 2.0, 0, 0.5);
CGContextMoveToPoint(ctx, touchStart.x, touchStart.y);
CGContextAddLineToPoint(ctx, touchCurrent.x, touchCurrent.y);
CGContextStrokePath(ctx);
drawIt=NO;
touchStart = touchCurrent = (CGPoint) { -1, -1 };
startIndexCol = startIndexRow = endIndexCol = endIndexRow = -1;
}
[[UIColor redColor] setStroke];
UIBezierPath *path = [UIBezierPath bezierPath];
[path moveToPoint:touchStart];
[path addLineToPoint:touchCurrent];
[path setLineWidth:20.0];
[path strokeWithBlendMode:kCGBlendModeNormal alpha:0.5];
// [path stroke];
}