我在试图解决这个问题时遇到了严重的困难。我的应用程序中有一个登陆页面，当我单击注册按钮时，应用程序将崩溃，并且我会收到此错误；
--------- beginning of crash
E/AndroidRuntime: FATAL EXCEPTION: main
Process: ie.app.barbershop, PID: 3181
java.lang.RuntimeException: Unable to start activity ComponentInfo{ie.app.barbershop/ie.app.barbershop.Landing}: java.lang.ClassCastException: android.support.v7.widget.AppCompatTextView cannot be cast to android.view.ViewGroup
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: java.lang.ClassCastException: android.support.v7.widget.AppCompatTextView cannot be cast to android.view.ViewGroup
at android.view.LayoutInflater.rInflate(LayoutInflater.java:807)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:809)
at android.view.LayoutInflater.inflate(LayoutInflater.java:504)
at android.view.LayoutInflater.inflate(LayoutInflater.java:414)
at android.view.LayoutInflater.inflate(LayoutInflater.java:365)
at android.support.v7.app.AppCompatDelegateImplV9.setContentView(AppCompatDelegateImplV9.java:287)
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:139)
at ie.app.barbershop.Landing.onCreate(Landing.java:23)
at android.app.Activity.performCreate(Activity.java:5990)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
I/Process: Sending signal. PID: 3181 SIG: 9
Application terminated.
这是我的 Landing.java 代码，我知道它与我的 setContent 有关，但我无法弄清楚
package ie.app.barbershop;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.ScrollView;
import android.widget.TextView;
import java.util.List;
public class Landing extends AppCompatActivity{
public Button buttonProducts;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.content_landing);
countRecords();
buttonProducts = findViewById(R.id.buttonProducts);
Button buttonCreateAppointment = findViewById(R.id.buttonCreateAppointment);
buttonCreateAppointment.setOnClickListener(new OnClickListenerCreateAppointment());
buttonProducts.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
startActivity(new Intent(Landing.this, Products.class));
}
});
}
public void readRecords() {
LinearLayout linearLayoutRecords = findViewById(R.id.linearLayoutRecords);
linearLayoutRecords.removeAllViews();
List<ObjectAppointment> appointments = new TableControllerAppointments(this).read();
if (appointments.size() > 0) {
for (ObjectAppointment obj : appointments) {
String fullName = obj.fullName;
int contactNumber = obj.contactNumber;
String textViewContents = fullName + " - " + contactNumber;
TextView textViewAppointmentItem= new TextView(this);
textViewAppointmentItem.setPadding(0, 10, 0, 10);
textViewAppointmentItem.setText(textViewContents);
textViewAppointmentItem.setTag(Integer.toString(contactNumber));
linearLayoutRecords.addView(textViewAppointmentItem);
}
}
else {
TextView locationItem = new TextView(this);
locationItem.setPadding(8, 8, 8, 8);
locationItem.setText("No records yet.");
linearLayoutRecords.addView(locationItem);
}
}
public void countRecords(){
int recordCount = new TableControllerAppointments(this).count();
TextView textViewRecordCount = findViewById(R.id.textViewRecordCount);
textViewRecordCount.setText(recordCount + " records found.");
}
}
此外，当我尝试在设计 View 中查看我的应用程序时，我收到此错误；
java.lang.ClassCastException: android.support.v7.widget.AppCompatTextView cannot be cast to android.view.ViewGroup
at android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:864)
at android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:72)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:837)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:824)
at android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:866)
at android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:72)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:837)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:824)
at android.view.LayoutInflater.inflate(LayoutInflater.java:515)
at android.view.LayoutInflater.inflate(LayoutInflater.java:394)
at com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate(RenderSessionImpl.java:325)
at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:384)
at com.android.tools.idea.layoutlib.LayoutLibrary.createSession(LayoutLibrary.java:193)
at com.android.tools.idea.rendering.RenderTask.createRenderSession(RenderTask.java:547)
at com.android.tools.idea.rendering.RenderTask.lambda$inflate$3(RenderTask.java:681)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
这是我的 XML 文件
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/backgroundbarbershop">
<ImageView
android:id="@+id/imageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="28dp"
android:layout_marginTop="16dp"
android:contentDescription="@string/galleryImage"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="@drawable/ic_camera_alt_black_36dp" />
<ImageView
android:id="@+id/imageView3"
android:layout_width="149dp"
android:layout_height="144dp"
android:layout_marginEnd="36dp"
android:layout_marginTop="16dp"
android:contentDescription="@string/gallery"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="@drawable/ic_shopping_cart_black_36dp" />
<ImageView
android:id="@+id/imageView11"
android:layout_width="149dp"
android:layout_height="144dp"
android:layout_marginBottom="20dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:contentDescription="@string/appointmentPicture"
app:layout_constraintBottom_toTopOf="@+id/buttonCreateAppointment"
app:layout_constraintEnd_toStartOf="@+id/imageView12"
app:layout_constraintHorizontal_bias="0.571"
app:layout_constraintStart_toStartOf="parent"
app:srcCompat="@drawable/book" />
<Button
android:id="@+id/buttonCreateAppointment"
android:layout_width="146dp"
android:layout_height="54dp"
android:layout_marginBottom="76dp"
android:layout_marginStart="28dp"
android:text="@string/buttonBookAppointment"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent" />
<Button
android:id="@+id/buttonProducts"
android:layout_width="146dp"
android:layout_height="38dp"
android:layout_marginEnd="36dp"
android:layout_marginTop="8dp"
android:text="@string/buttonProducts"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="@+id/imageView3" />
<Button
android:id="@+id/buttonGallery"
android:layout_width="145dp"
android:layout_height="37dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:text="@string/buttonGallery"
app:layout_constraintBottom_toTopOf="@+id/imageView11"
app:layout_constraintEnd_toStartOf="@+id/buttonProducts"
app:layout_constraintHorizontal_bias="0.487"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/imageView"
app:layout_constraintVertical_bias="0.0" />
<Button
android:id="@+id/button4"
android:layout_width="140dp"
android:layout_height="55dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:text="@string/contactUsButton"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.314"
app:layout_constraintStart_toEndOf="@+id/buttonCreateAppointment"
app:layout_constraintTop_toBottomOf="@+id/imageView12"
app:layout_constraintVertical_bias="0.157" />
<ImageView
android:id="@+id/imageView12"
android:layout_width="wrap_content"
android:layout_height="144dp"
android:layout_marginEnd="40dp"
android:layout_marginTop="8dp"
android:contentDescription="@string/contact"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="@+id/buttonProducts"
app:srcCompat="@drawable/ic_contact_phone_black_36dp" />
<TextView
android:id="@+id/textViewRecordCount"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:padding="1dp"
android:text="@string/textViewRecordCount"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.182"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/buttonCreateAppointment"
app:layout_constraintVertical_bias="0.146" >
<LinearLayout
android:id="@+id/linearLayoutRecords"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
</LinearLayout>
</TextView>
</android.support.constraint.ConstraintLayout>
最佳答案
您的 TextView 中有一个 LinearLayout:
<TextView
android:id="@+id/textViewRecordCount"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:padding="1dp"
android:text="@string/textViewRecordCount"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.182"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/buttonCreateAppointment"
app:layout_constraintVertical_bias="0.146" >
<LinearLayout
android:id="@+id/linearLayoutRecords"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
</LinearLayout>
</TextView>
如果您刚刚删除了线性布局应该可以正常工作。 TextView 不是 View Group，因此您不能在其中包含任何内容。这就是为什么你会得到:
AppCompatTextView cannot be cast to android.view.ViewGroup
关于java - 单击注册按钮时应用程序不断崩溃并且在设计模式下不显示预览？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/49898841/