我知道哪一行有错误，但如何解决？

Question

我看过nullpointerexception错误，但是我找不到用谷歌搜索过的代码的解决方案，但是没有解决方案。您可以在下面看到我的代码

public class oyuncuAdlariActivity extends AppCompatActivity {
Button kaleciKayit;
Button oyuncuKayit;
EditText isimGiris;
String isimGirisString;
int kaleciSayisi = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_oyuncu_adlari);
    kaleciKayit = (Button) findViewById(R.id.kaleciButton);
    oyuncuKayit = (Button) findViewById(R.id.oyuncuButton);
    isimGiris = (EditText) findViewById(R.id.isimGir);
    kaleciKayit.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            kaleciSayisi++;
            isimGirisString = isimGiris.getText().toString();
            if (isimGirisString.isEmpty()){
                Toast toast1 = Toast.makeText(getApplicationContext(),getApplicationContext().getString(R.string.isimBos), Toast.LENGTH_SHORT);
                toast1.show();
            }
            else if (kaleciSayisi >2)
                kaleciKayit.setEnabled(false);
        }
    });
}

} 当我检查logcat时，它说第24行有“ nullpointexception”问题 第24行是

kaleciKayit.setOnClickListener(new View.OnClickListener() {

这有什么问题？我检查了布局是否正确 这是activity_oyuncu_adlari.xml文件

    <Button
        android:id="@+id/oyuncuButton"
        android:layout_width="227dp"
        android:layout_height="52dp"
        android:text="@string/oyuncu_olarak_kaydet"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.434" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/isimleri_buraya_girin"
        android:textSize="20sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.497"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.133" />

    <EditText
        android:id="@+id/isimGir"
        android:layout_width="227dp"
        android:layout_height="52dp"
        android:ems="10"
        android:importantForAutofill="no"
        android:inputType="textPersonName"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.188" />

    <Button
        android:id="@+id/kaleciButton"
        android:layout_width="227dp"
        android:layout_height="52dp"
        android:text="@string/kaleci"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.313" />