如果是地图键的链，则为惯用语

Question

我有一个相当长的时间，如果链在地图中寻找键并设置特定值，如果找到。我选择使用最少代码执行此操作的方式是这样的（ 05-27 05:57:34.482: D/BONUSPACK(8392): GeocoderNominatim::getFromLocationName:http://nominatim.openstreetmap.org/search?format=json&accept-language=en&addressdetails=1&limit=1&q=Bolivia 05-27 05:57:34.512: W/System.err(8392): android.os.NetworkOnMainThreadException 05-27 05:57:34.512: W/System.err(8392): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1145) 05-27 05:57:34.523: W/System.err(8392): at java.net.InetAddress.lookupHostByName(InetAddress.java:385) 05-27 05:57:34.523: W/System.err(8392): at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236) 05-27 05:57:34.523: W/System.err(8392): at java.net.InetAddress.getAllByName(InetAddress.java:214) 05-27 05:57:34.523: W/System.err(8392): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137) 05-27 05:57:34.523: W/System.err(8392): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164) 05-27 05:57:34.523: W/System.err(8392): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119) 05-27 05:57:34.533: W/System.err(8392): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360) 05-27 05:57:34.533: W/System.err(8392): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555) 05-27 05:57:34.533: W/System.err(8392): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487) 05-27 05:57:34.533: W/System.err(8392): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465) 05-27 05:57:34.533: W/System.err(8392): at org.osmdroid.bonuspack.utils.HttpConnection.doGet(HttpConnection.java:73) 05-27 05:57:34.543: W/System.err(8392): at org.osmdroid.bonuspack.utils.BonusPackHelper.requestStringFromUrl(BonusPackHelper.java:71) 05-27 05:57:34.543: W/System.err(8392): at org.osmdroid.bonuspack.location.GeocoderNominatim.getFromLocationName(GeocoderNominatim.java:225) 05-27 05:57:34.543: W/System.err(8392): at org.osmdroid.bonuspack.location.GeocoderNominatim.getFromLocationName(GeocoderNominatim.java:271) 05-27 05:57:34.543: W/System.err(8392): at com.example.GeocoderNominatim.MainActivity$MapFragment.onCreateView(MainActivity.java:340) 05-27 05:57:34.543: W/System.err(8392): at android.app.Fragment.performCreateView(Fragment.java:1700) 05-27 05:57:34.543: W/System.err(8392): at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:890) 05-27 05:57:34.553: W/System.err(8392): at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1062) 05-27 05:57:34.553: W/System.err(8392): at android.app.BackStackRecord.run(BackStackRecord.java:684) 05-27 05:57:34.553: W/System.err(8392): at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1447) 05-27 05:57:34.553: W/System.err(8392): at android.app.FragmentManagerImpl$1.run(FragmentManager.java:443) 05-27 05:57:34.553: W/System.err(8392): at android.os.Handler.handleCallback(Handler.java:733) 05-27 05:57:34.553: W/System.err(8392): at android.os.Handler.dispatchMessage(Handler.java:95) 05-27 05:57:34.563: W/System.err(8392): at android.os.Looper.loop(Looper.java:136) 05-27 05:57:34.573: W/System.err(8392): at android.app.ActivityThread.main(ActivityThread.java:5146) 05-27 05:57:34.573: W/System.err(8392): at java.lang.reflect.Method.invokeNative(Native Method) 05-27 05:57:34.573: W/System.err(8392): at java.lang.reflect.Method.invoke(Method.java:515) 05-27 05:57:34.573: W/System.err(8392): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:732) 05-27 05:57:34.573: W/System.err(8392): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:566) 05-27 05:57:34.573: W/System.err(8392): at dalvik.system.NativeStart.main(Native Method) 是m）

map[string]interface{}

这感觉有点笨重，我正在做所有这些var ok bool var s interface{} if s, ok = m["key1"]; ok { } else if s, ok = m["key2"]; ok { .... } else if s, ok = m["keyN"]; ok { } else { return RuhRohError } g.Id = s.(string) 来设置条件中的变量。这是否有惯用的方法？我认为这种做法并没有立即显示我想要做的事情。

Answer 1

例如，

for feature in features as! [CIQRCodeFeature]

输出：

package main

import "fmt"

func findValue(m map[string]interface{}, keys []string) (interface{}, bool) {
    for _, key := range keys {
        if value, ok := m[key]; ok {
            return value, true
        }
    }
    return nil, false
}

func main() {
    m := map[string]interface{}{"keyn": "valuen"}
    keys := []string{"key1", "key2", "keyn"}
    s, found := findValue(m, keys)
    if !found {
        return
    }
    id := s.(string)
    fmt.Println(id)
}

Answer 2

实际上我认为您提供的代码非常易于阅读和理解。它有点冗长，但没有魔法;）。因此，如果只有一个地方你必须编写这段代码，我会保留原样。如果你需要写几次，我会考虑编写另一条评论中提到的findValue函数。