我无法从一个 activity 切换到另一个 activity，我在清单上遇到了问题

Question

你好朋友，我的意图有问题，我正在尝试转到另一个 activity 但我的应用程序被破坏了，在 logcat 我看到那个消息（android.content.ActivityNotFoundException : 无法找到明确的 activity class {com.example.project35cardview / com.example.proyecto35ca.MainActivitycardView}；您是否在 [=33= 中声明了此 activity ]?) 我转到清单并尝试从清单中调用它，但只出现了两个活动。

logcat

2020-08-08 07:15:11.600 28853-28853/? E/yecto35cardvie: Unknown bits set in runtime_flags: 0x8000
2020-08-08 07:15:11.663 28853-28853/? E/libc: Access denied finding property "runtime.mmitest.isrunning"
2020-08-08 07:15:12.117 28853-28888/com.example.proyecto35cardview E/AwareLog: AtomicFileUtils: readFileLines file not exist: android.util.AtomicFile@1108279
2020-08-08 07:15:12.119 28853-28888/com.example.proyecto35cardview E/AwareLog: AtomicFileUtils: readFileLines file not exist: android.util.AtomicFile@e5e9bbe
2020-08-08 07:15:15.146 28853-28853/com.example.proyecto35cardview E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.proyecto35cardview, PID: 28853
    android.content.ActivityNotFoundException: Unable to find explicit activity class {com.example.proyecto35cardview/com.example.proyecto35ca.MainActivitycardView}; have you declared this activity in your AndroidManifest.xml?
        at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:2111)
        at android.app.Instrumentation.execStartActivity(Instrumentation.java:1739)
        at android.app.Activity.startActivityForResult(Activity.java:5363)
        at androidx.fragment.app.FragmentActivity.startActivityForResult(FragmentActivity.java:676)
        at android.app.Activity.startActivityForResult(Activity.java:5304)
        at androidx.fragment.app.FragmentActivity.startActivityForResult(FragmentActivity.java:663)
        at android.app.Activity.startActivity(Activity.java:5734)
        at android.app.Activity.startActivity(Activity.java:5702)
        at com.example.proyecto35cardview.MainActivity$onCreate.onClick(MainActivity.kt:22)
        at android.view.View.performClick(View.java:7192)
        at android.view.View.performClickInternal(View.java:7166)
        at android.view.View.access00(View.java:824)
        at android.view.View$PerformClick.run(View.java:27592)
        at android.os.Handler.handleCallback(Handler.java:888)
        at android.os.Handler.dispatchMessage(Handler.java:100)
        at android.os.Looper.loop(Looper.java:213)
        at android.app.ActivityThread.main(ActivityThread.java:8178)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:513)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1101)

我的代码

 card_view.setOnClickListener {
          val intent = Intent (this,MainActivitycardView::class.java
            startActivity(intent)//line 22
            }

清单

问题（我尝试调用 MainActivity cardView 但它只显示两个活动）

MainActivitycardView

 override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main_activitycard_view)

        //Se debe crear un vector de tipo MediaPlayer de 3 posiciones porque tengo 3 canciones
        val vectoMp3 = arrayOfNulls<MediaPlayer>(3)
        var repetir = 2
        var position = 0
        vectoMp3[0]= MediaPlayer.create(this,R.raw.race)
        vectoMp3[1] = MediaPlayer.create(this,R.raw.sound)
        vectoMp3[2]=MediaPlayer.create(this,R.raw.tea)

        //Metodo para pausar la canción
        buttonPlay.setOnClickListener {
            if (vectoMp3[position]?.isPlaying!!){
                vectoMp3[position]?.pause()
                //Metodo para cambiar imagen del boton
                buttonPlay.setBackgroundResource(R.drawable.reproducir)
                Toast.makeText(this ,"Pausa", Toast.LENGTH_SHORT).show()
            } else {
                vectoMp3[position]?.start()
                buttonPlay.setBackgroundResource(R.drawable.pausa)
                Toast.makeText(this ,"Play", Toast.LENGTH_SHORT).show()
            }
        }

        //Metodo para detener una canción
        buttonStop.setOnClickListener {
            if (vectoMp3[position] !=null){
                vectoMp3[position]?.stop()
                //Se debe colocar los vectores para que el boton  sepa que va a pausar
                vectoMp3[0]= MediaPlayer.create(this,R.raw.race)
                vectoMp3[1] = MediaPlayer.create(this,R.raw.sound)
                vectoMp3[2]=MediaPlayer.create(this,R.raw.tea)
                position = 0
                buttonPlay.setBackgroundResource(R.drawable.reproducir)
                //Metodo para volver a la portada 1
                imageView.setBackgroundResource(R.drawable.portada1)
                Toast.makeText(this, "Stop", Toast.LENGTH_SHORT).show()
            }
        }
        //Metodo para repetir una pista
        button4.setOnClickListener {
            if (repetir==1){
                button4.setBackgroundResource(R.drawable.no_repetir)
                Toast.makeText(this, "No repetor", Toast.LENGTH_SHORT).show()
                vectoMp3[position]?.isLooping  = false
                repetir = 2
            } else {
                button4.setBackgroundResource(R.drawable.repetir)
                Toast.makeText(this, "Repetir", Toast.LENGTH_SHORT).show()
                vectoMp3[position]?.isLooping  = true
                repetir = 1
            }
        }

    }
}

Answer 1

请显示您的 class MainActivitycardView.java 的定义。希望你像这样扩展它：

public class MainActivitycardView extends AppCompatActivity { 
    //body of the class 
}

我无法从一个 activity 切换到另一个 activity，我在清单上遇到了问题

I can't switch from one activity to another and I have a problem at the manisfest

java

android

android-manifest

kotlin