Android Studio Kotlin：单击时按钮不断导致崩溃

Question

所以我是编码新手，我正在 Android Studio 和 Kotlin 中制作一个应用程序，在我的应用程序主页上，我有一个按钮可以将我带到另一个 activity 并且每次我点击它，应用程序崩溃。我想知道如何解决这个问题，以及它是代码错误还是内存错误。提前致谢！

代码如下：

package com.smvcalculator

import android.content.Intent
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Button

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        val MaleLP = findViewById<Button>(R.id.malebtn)
        MaleLP.setOnClickListener {
            val intent = Intent(this, MaleLP::class.java)
            startActivity(intent)
        }

    }
}

Logcat 错误：

2021-07-14 14:51:57.879 9421-9421/com.smvcalculator E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.smvcalculator, PID: 9421
    android.content.ActivityNotFoundException: Unable to find explicit activity class {com.smvcalculator/com.google.android.material.button.MaterialButton}; have you declared this activity in your AndroidManifest.xml?
        at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:2065)
        at android.app.Instrumentation.execStartActivity(Instrumentation.java:1727)
        at android.app.Activity.startActivityForResult(Activity.java:5320)
        at androidx.activity.ComponentActivity.startActivityForResult(ComponentActivity.java:574)
        at android.app.Activity.startActivityForResult(Activity.java:5278)
        at androidx.activity.ComponentActivity.startActivityForResult(ComponentActivity.java:560)
        at android.app.Activity.startActivity(Activity.java:5664)
        at android.app.Activity.startActivity(Activity.java:5617)
        at com.smvcalculator.MainActivity.onCreate$lambda-0(MainActivity.kt:15)
        at com.smvcalculator.MainActivity.lambda$pO9IRxlIimBerH3k2cIfwv6P3Wg(Unknown Source:0)
        at com.smvcalculator.-$$Lambda$MainActivity$pO9IRxlIimBerH3k2cIfwv6P3Wg.onClick(Unknown Source:4)
        at android.view.View.performClick(View.java:7448)
        at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:1119)
        at android.view.View.performClickInternal(View.java:7425)
        at android.view.View.access$3600(View.java:810)
        at android.view.View$PerformClick.run(View.java:28305)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        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)
2021-07-14 14:51:58.073 9421-9421/com.smvcalculator I/Process: Sending signal. PID: 9421 SIG: 9

Answer 1

我想这里的问题是，它说have you declared this activity in your AndroidManifest.xml? 所以你需要在你的AndroidManifest.xml 文件中添加这个活动的名称，即MaleLP.java，如下所示：

<activity
        android:name=".MaleLP"
       />

Answer 2

我终于找到了错误。您的 Button 与将用于 intent 的 Activity 具有相同的名称。改成这样：

package com.smvcalculator

import android.content.Intent
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Button

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        val maleLP_button = findViewById<Button>(R.id.malebtn) //new button name
        maleLP_button.setOnClickListener {
            val intent = Intent(this, MaleLP::class.java) //different to class name
            startActivity(intent)
        }
    }
}

现在应该可以了:)