如何实现MKMapView搜索

对原理有兴趣请参见具体的出处#import#import@interfaceMKMapView(MapViewUtil)-(void)setCenterCoordinate:(CLLocationCoordinate2D)centerCoordinatezoomLevel:(NSUInteger)zoomLevelanimated:(BOOL)animated;@end#import"MapViewUtilh"#defineMERCATOR_OFFSET268435456#defineMERCATOR_RADIUS8544565944705395@implementationMKMapView(MapViewUtil)#pragmamark-#pragmamarkMapconversionmethods-(double)longitudeToPixelSpaceX:(double)longitude{returnround(MERCATOR_OFFSET+MERCATOR_RADIUSlongitudeM_PI/1800);}-(double)latitudeToPixelSpaceY:(double)latitude{returnround(MERCATOR_OFFSET-MERCATOR_RADIUSlogf((1+sinf(latitudeM_PI/1800))/(1-sinf(latitudeM_PI/1800)))/20);}-(double)pixelSpaceXToLongitude:(double)pixelX{return((round(pixelX)-MERCATOR_OFFSET)/MERCATOR_RADIUS)1800/M_PI;}-(double)pixelSpaceYToLatitude:(double)pixelY{return(M_PI/20-20atan(exp((round(pixelY)-MERCATOR_OFFSET)/MERCATOR_RADIUS)))1800/M_PI;}#pragmamark-#pragmamarkHelpermethods-(MKCoordinateSpan)coordinateSpanWithMapView:(MKMapView)mapViewcenterCoordinate:(CLLocationCoordinate2D)centerCoordinateandZoomLevel:(NSUInteger)zoomLevel{//convertcentercoordiatetopixelspacedoublecenterPixelX=[selflongitudeToPixelSpaceX:centerCoordinatelongitude];doublecenterPixelY=[selflatitudeToPixelSpaceY:centerCoordinatelatitude];//determinethescalevaluefromthezoomlevelNSIntegerzoomExponent=20-zoomLevel;doublezoomScale=pow(2,zoomExponent);//scalethemap’ssizeinpixelspaceCGSizemapSizeInPixels=mapViewboundssize;doublescaledMapWidth=mapSizeInPixelswidthzoomScale;doublescaledMapHeight=mapSizeInPixelsheightzoomScale;//figureoutthepositionofthetop-leftpixeldoubletopLeftPixelX=centerPixelX-(scaledMapWidth/2);doubletopLeftPixelY=centerPixelY-(scaledMapHeight/2);//finddeltabetweenleftandrightlongitudesCLLocationDegreesminLng=[selfpixelSpaceXToLongitude:topLeftPixelX];CLLocationDegreesmaxLng=[selfpixelSpaceXToLongitude:topLeftPixelX+scaledMapWidth];CLLocationDegreeslongitudeDelta=maxLng-minLng;//finddeltabetweentopandbottomlatitudesCLLocationDegreesminLat=[selfpixelSpaceYToLatitude:topLeftPixelY];CLLocationDegreesmaxLat=[selfpixelSpaceYToLatitude:topLeftPixelY+scaledMapHeight];CLLocationDegreeslatitudeDelta=-1(maxLat-minLat);//createandreturnthelat/lngspanMKCoordinateSpanspan=MKCoordinateSpanMake(latitudeDelta,longitudeDelta);returnspan;}#pragmamark-#pragmamarkPublicmethods-(void)setCenterCoordinate:(CLLocationCoordinate2D)centerCoordinatezoomLevel:(NSUInteger)zoomLevelanimated:(BOOL)animated{//clamplargenumbersto28zoomLevel=MIN(zoomLevel,28);//usethezoomleveltocomputetheregionMKCoordinateSpanspan=[selfcoordinateSpanWithMapView:selfcenterCoordinate:centerCoordinateandZoomLevel:zoomLevel];MKCoordinateRegionregion=MKCoordinateRegionMake(centerCoordinate,span);//settheregion

sister 英[ˈsɪstə(r)] 美[ˈsɪstɚ]

n 姐妹; 修女; （称志同道合者） 姐妹; 护士;

adj 姐妹般的; 同类型的;

v 如姐妹般相待;

[例句]His sister Sarah helped him

他姐姐萨拉帮助了他。

[其他] 复数：sisters 形近词： lister pister sistcr

younger sister

[词典] 妹；妹子；娣；女弟;

[例句]As a child she fought with her younger sister

她小时候会和妹妹打架。

双语例句

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