獲得一個企圖指數當地「我的地圖」（一個零值）

Question

我是新來使用corona sdk.

我試圖添加引腳映射視圖把我的代碼加入到做我不斷收到這個錯誤

企圖指數當地「我的地圖」（一個零值）

我看的東西了，有人也有類似的問題，他們只是有當地MYMAP添加到頂部。我試過了，但沒有奏效。我希望有人能幫我找出問題所在。

感謝您的幫助=）

local widget = require("widget") 
local myMap 

local locationNumber = 1 -- a counter to display on location labels 
local currentLocation, currentLatitude, currentLongitude 

local background = display.newImage("bkg_grass.png", true) 
background.x = display.contentWidth/2 
background.y = display.contentHeight/2 

local shadow = display.newRect(7, 7, 306, 226) 
shadow.anchorX = 0.0  -- TopLeft anchor 
shadow.anchorY = 0.0  -- TopLeft anchor 
shadow:setFillColor(0, 0, 0, 120/255) 

local simulatorMessage = "Maps not supported in Corona Simulator.\n\nYou must build for iOS or Android to test MapView support." 
local label = display.newText(simulatorMessage, 20, 70, shadow.contentWidth - 10, 0, native.systemFont, 14) 
label.anchorX = 0.0  -- TopLeft anchor 
label.anchorY = 0.0  -- TopLeft anchor 


local myMap = native.newMapView(20, 20, display.contentWidth, display.actualContentHeight*.7) 

if myMap then 
    myMap.mapType = "normal" 
    myMap.x = display.contentWidth/2 
    myMap.y = 400 
    myMap:setCenter(37.331692, -122.030456) 
end 

local function markerListener(event) 
    print("type: ", event.type) -- event 
    print("markerId: ", event.markerId) -- if of the marker that was touched 
    print("lat: ", event.latitude) -- latitude of the marker 
    print("long: ", event.longitude) -- longitude of the marker 
end 

local options = 
{ 
    title = "Displayed Title", 
    subtitle = "subtitle text", 
    listener = markerListener, 
    imageFile = 
    { 
     filename = "someImage.png", 
     baseDir = system.TemporaryDirectory 
    } 
} 

local options1 = 
{ 
    title = "Displayed Title", 
    subtitle = "subtitle text", 
    listener = markerListener, 
    imageFile = "someImage.png", 
} 

local result, errorMessage = myMap:addMarker(37.331692, -122.030456, options) 
if result then 
    print("everything went well") 
else 
    print(errorMessage) 
end 

-- A function to handle the "mapAddress" event (also known as "reverse geocoding", ie: coordinates -> string). 
local mapAddressHandler = function(event) 
    if event.isError then 
     -- Failed to receive location information. 
     native.showAlert("Error", event.errorMessage, { "OK" }) 
    else 
     -- Location information received. Display it. 
     local locationText = 
       "Latitude: " .. currentLatitude .. 
       ", Longitude: " .. currentLongitude .. 
       ", Address: " .. (event.streetDetail or "") .. 
       " " .. (event.street or "") .. 
       ", " .. (event.city or "") .. 
       ", " .. (event.region or "") .. 
       ", " .. (event.country or "") .. 
       ", " .. (event.postalCode or "") 
     native.showAlert("You Are Here", locationText, { "OK" }) 
    end 
end 

-- A function to handle the "mapLocation" event (also known as "forward geocoding", ie: string -> coordinates). 
local mapLocationHandler = function(event) 
    if event.isError then 
     -- Location name not found. 
     native.showAlert("Error", event.errorMessage, { "OK" }) 
    else 
     -- Move map so this location is at the center 
     -- (The final parameter toggles map animation, which may not be visible if moving a large distance) 
     myMap:setCenter(event.latitude, event.longitude, true) 

     -- Add a pin to the map at the new location 
     markerTitle = "Location " .. locationNumber 
     locationNumber = locationNumber + 1 
     myMap:addMarker(event.latitude, event.longitude, { title=markerTitle, subtitle=inputField.text }) 
    end 
end 

Answer 1

這可能是因爲無論是local myMap = native.newMapView(20, 20, display.contentWidth, display.actualContentHeight*.7)返回零或功能沿途設置myMap爲零。

我注意到，在兩個地方，你在函數的頂部參考MYMAP沒有先檢查零，不像：

local result, errorMessage = myMap:addMarker(37.331692, -122.030456, options)

myMap:setCenter(event.latitude, event.longitude, true)

很可能在這一個吹起來兩個地方。我會檢查local myMap = native.newMapView(20, 20, display.contentWidth, display.actualContentHeight*.7)是否失敗，或者你的某個函數是否將myMap設置爲零。