使用Kotlin使用OkHTTTP运行Android studio应用程序时发生实例化错误
使用OkHTTP,我试图检索一个文本文件,并将hat放入主活动的使用Kotlin使用OkHTTTP运行Android studio应用程序时发生实例化错误,android,android-studio,kotlin,okhttp,Android,Android Studio,Kotlin,Okhttp,使用OkHTTP,我试图检索一个文本文件,并将hat放入主活动的textView, Gradle会说build successful,但emulator应用程序将在启动时崩溃,并提供此错误 我已经在AndroidManifest.xml中添加了正确的权限,并在gradle构建中添加了正确的实现 package com.example.vectortestapi import android.os.Bundle import android.widget.TextView import andr
textView
,
Gradle会说build successful,但emulator应用程序将在启动时崩溃,并提供此错误
我已经在AndroidManifest.xml
中添加了正确的权限,并在gradle构建中添加了正确的实现
package com.example.vectortestapi
import android.os.Bundle
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity
import okhttp3.*
import java.io.IOException
abstract class MainActivity : AppCompatActivity() {
private val mTextView: TextView = findViewById<TextView>(R.id.resultText);
private val client = OkHttpClient()
private val url = "https://publicobject.com/helloworld.txt"
private val request: Request = Request.Builder()
.url(url)
.build();
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
getAPI();
}
private fun getAPI(){
client.newCall(request).enqueue(object: Callback {
override fun onFailure(call: Call, e: IOException) {
e.printStackTrace()
}
override fun onResponse(call: Call, response: Response) {
val inputStream = response.body?.string()
runOnUiThread{
mTextView.text = inputStream
}
}
})
}
}
package com.example.vectortestapi
导入android.os.Bundle
导入android.widget.TextView
导入androidx.appcompat.app.appcompat活动
进口okhttp3*
导入java.io.IOException
抽象类MainActivity:AppCompatActivity(){
private val mTextView:TextView=findviewbyd(R.id.resultText);
private val client=OkHttpClient()
私有值url=”https://publicobject.com/helloworld.txt"
private val request:request=request.Builder()
.url(url)
.build();
重写创建时的乐趣(savedInstanceState:Bundle?){
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
getAPI();
}
私人娱乐getAPI(){
client.newCall(请求).enqueue(对象:回调{
覆盖失效(调用:调用,e:IOException){
e、 printStackTrace()
}
覆盖fun onResponse(调用:调用,响应:响应){
val inputStream=response.body?.string()
runOnUiThread{
mTextView.text=inputStream
}
}
})
}
}
产生以下错误:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.vectortestapi, PID: 9900
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.vectortestapi/com.example.vectortestapi.MainActivity}: java.lang.InstantiationException: java.lang.Class<com.example.vectortestapi.MainActivity> cannot be instantiated
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3365)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
Caused by: java.lang.InstantiationException: java.lang.Class<com.example.vectortestapi.MainActivity> cannot be instantiated
at java.lang.Class.newInstance(Native Method)
at android.app.AppComponentFactory.instantiateActivity(AppComponentFactory.java:95)
at androidx.core.app.CoreComponentFactory.instantiateActivity(CoreComponentFactory.java:45)
at android.app.Instrumentation.newActivity(Instrumentation.java:1253)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3353)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
D/libEGL: loaded /vendor/lib/egl/libGLESv2_emulation.so
I/Process: Sending signal. PID: 9900 SIG: 9
E/AndroidRuntime:致命异常:主
进程:com.example.vectortestapi,PID:9900
java.lang.RuntimeException:无法实例化活动组件信息{com.example.vectortestapi/com.example.vectortestapi.MainActivity}:java.lang.InstantiationException:无法实例化java.lang.Class
在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3365)上
位于android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601)
在android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
在android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)中
在android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)中
在android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
位于android.os.Handler.dispatchMessage(Handler.java:106)
位于android.os.Looper.loop(Looper.java:223)
位于android.app.ActivityThread.main(ActivityThread.java:7656)
位于java.lang.reflect.Method.invoke(本机方法)
位于com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
位于com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
原因:java.lang.InstantiationException:无法实例化java.lang.Class
位于java.lang.Class.newInstance(本机方法)
位于android.app.AppComponentFactory.InstanceActivity(AppComponentFactory.java:95)
位于androidx.core.app.CoreComponentFactory.InstanceActivity(CoreComponentFactory.java:45)
位于android.app.Instrumentation.newActivity(Instrumentation.java:1253)
在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3353)上
位于android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601)
在android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
在android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)中
在android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)中
在android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
位于android.os.Handler.dispatchMessage(Handler.java:106)
位于android.os.Looper.loop(Looper.java:223)
位于android.app.ActivityThread.main(ActivityThread.java:7656)
位于java.lang.reflect.Method.invoke(本机方法)
位于com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
位于com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
D/libEGL:load/vendor/lib/egl/libGLESv2_emulation.so
I/进程:发送信号。PID:9900信号:9
抽象类不能被实例化,但它们可以被子类化。所以必须更改什么,因为简单地删除抽象(因为它不需要是抽象类)仍然会导致错误