如何解决Android Kotlin中的HTTP请求
我尝试使用android studio中java.net.url中的URL.readText()
获取JSON或类似的内容,但是我的应用程序崩溃了。
fun ButtonClick(view:View) {
textView.text = URL("https://www.google.com/robots.txt").readText()
}
我也将此添加到manifest.xml
<uses-permission android:name="android.permission.INTERNET" />
但还是会崩溃
请帮帮我!我究竟做错了什么?。我认为使用url.readText从url获取文本是可以的,因为这篇帖子HTTP Request in Kotlin中的某个人写道,这样更简单
崩溃日志:
2020-08-17 23:16:04.117 2251-2251/com.example.myapplication E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.myapplication,PID: 2251
java.lang.IllegalStateException: Could not execute method for android:onClick
at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:414)
at android.view.View.performClick(View.java:5637)
at android.view.View$PerformClick.run(View.java:22429)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:409)
at android.view.View.performClick(View.java:5637)
at android.view.View$PerformClick.run(View.java:22429)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
Caused by: android.os.NetworkOnMainThreadException
at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1303)
at java.net.Inet6AddressImpl.lookupHostByName(Inet6AddressImpl.java:86)
at java.net.Inet6AddressImpl.lookupAllHostAddr(Inet6AddressImpl.java:74)
at java.net.InetAddress.getAllByName(InetAddress.java:752)
at com.android.okhttp.internal.Network$1.resolveInetAddresses(Network.java:29)
at com.android.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:187)
at com.android.okhttp.internal.http.RouteSelector.nextProxy(RouteSelector.java:156)
at com.android.okhttp.internal.http.RouteSelector.next(RouteSelector.java:98)
at com.android.okhttp.internal.http.HttpEngine.createNextConnection(HttpEngine.java:345)
at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:328)
at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:246)
at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:457)
at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:405)
at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:243)
at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.getInputStream(DelegatingHttpsURLConnection.java:210)
at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java)
at java.net.URL.openStream(URL.java:1057)
at kotlin.io.TextStreamsKt.readBytes(ReadWrite.kt:150)
at com.example.myapplication.MainActivity.ButtonClick(MainActivity.kt:25)
at java.lang.reflect.Method.invoke(Native Method)
at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:409)
at android.view.View.performClick(View.java:5637)
at android.view.View$PerformClick.run(View.java:22429)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
解决方法
根据您提供的有限信息,您可能需要NetworkOnMainThreadException
将代码包装在线程中才能正常工作
fun ButtonClick(view:View){
thread {
val response = URL("https://www.google.com/robots.txt").readText()
activity?.runOnUiThread{
textView.text = response
}
}
}
,
我遇到了这个问题,但没有解决
但是现在我在android中使用Volley,它确实功能强大且简单
我建议您与Volley合作
,您应该在代码的改造中使用
1-在应用程序级别build.gradle文件中添加以下几行,以将Google Services应用于您的项目
dependencies {
...
Implementation 'org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version'
implementation 'com.squareup.retrofit2:retrofit:2.0.0'
implementation 'com.squareup.retrofit2:converter-gson:2.0.0'
}
2-然后,单击“立即同步”以设置您的项目。
3-不要忘记在清单文件中添加以下权限
<uses-permission android:name="android.permission.INTERNET"/>
4-创建一个名为“ WeatherService.kt”的接口文件,并在其中添加以下行
interface WeatherService {
@GET("data/2.5/weather?")
fun getCurrentWeatherData(@Query("lat") lat: String,@Query("lon") lon: String,@Query("APPID") app_id: String): Call<WeatherResponse>
}
5-创建一个名为“ WeatherResponse.kt”的类文件,并添加以下行。在这里,我们使用了Gson转换器,因此JSON响应会自动转换为相应的内容,并且转换器会将响应树与序列化名称进行比较。
class WeatherResponse {
@SerializedName("coord")
var coord: Coord? = null
@SerializedName("sys")
var sys: Sys? = null
@SerializedName("weather")
var weather = ArrayList<Weather>()
@SerializedName("main")
var main: Main? = null
@SerializedName("wind")
var wind: Wind? = null
@SerializedName("rain")
var rain: Rain? = null
@SerializedName("clouds")
var clouds: Clouds? = null
@SerializedName("dt")
var dt: Float = 0.toFloat()
@SerializedName("id")
var id: Int = 0
@SerializedName("name")
var name: String? = null
@SerializedName("cod")
var cod: Float = 0.toFloat()
}
class Weather {
@SerializedName("id")
var id: Int = 0
@SerializedName("main")
var main: String? = null
@SerializedName("description")
var description: String? = null
@SerializedName("icon")
var icon: String? = null
}
class Clouds {
@SerializedName("all")
var all: Float = 0.toFloat()
}
class Rain {
@SerializedName("3h")
var h3: Float = 0.toFloat()
}
class Wind {
@SerializedName("speed")
var speed: Float = 0.toFloat()
@SerializedName("deg")
var deg: Float = 0.toFloat()
}
class Main {
@SerializedName("temp")
var temp: Float = 0.toFloat()
@SerializedName("humidity")
var humidity: Float = 0.toFloat()
@SerializedName("pressure")
var pressure: Float = 0.toFloat()
@SerializedName("temp_min")
var temp_min: Float = 0.toFloat()
@SerializedName("temp_max")
var temp_max: Float = 0.toFloat()
}
class Sys {
@SerializedName("country")
var country: String? = null
@SerializedName("sunrise")
var sunrise: Long = 0
@SerializedName("sunset")
var sunset: Long = 0
}
class Coord {
@SerializedName("lon")
var lon: Float = 0.toFloat()
@SerializedName("lat")
var lat: Float = 0.toFloat()
}
6-然后,打开您的Activity文件,就我而言,我已经打开了MainActivity.kt文件。然后,使用基本URL和GsonConverterFactory创建一个Retrofit Builder。
val retrofit = Retrofit.Builder()
.baseUrl(BaseUrl)
.addConverterFactory(GsonConverterFactory.create())
.build()
7-然后,使用服务界面为Retrofit创建服务,如下所示
val service = retrofit.create(WeatherService::class.java)
val call = service.getCurrentWeatherData(lat,lon,AppId)
此处,“ getCurrentWeatherData”是在“ WeatherService”界面中创建的界面功能。
8-然后,使用Weather Response创建一个队列,该队列用于反序列化Open Weather API的JSON输出。下面将显示创建的队列。
call.enqueue(object : Callback<WeatherResponse> {
override fun onResponse(call: Call<WeatherResponse>,response:
Response<WeatherResponse>) {
if (response.code() == 200) {
…
}
}
override fun onFailure(call: Call<WeatherResponse>,t: Throwable) {
…
}
})
定义的变量:
companion object {
var BaseUrl = "http://api.openweathermap.org/"
var AppId = "2e65127e909e178d0af311a81f39948c"
var lat = "35"
var lon = "139"
}
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