我的应用程序显示运行时异常，当我试图从Android Studio在我的手机上运行它时

Question

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.courtcounter, PID: 22809
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.courtcounter/com.example.courtcounter.MainActivity}: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3521)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3660)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2242)
        at android.os.Handler.dispatchMessage(Handler.java:107)
        at android.os.Looper.loop(Looper.java:230)
        at android.app.ActivityThread.main(ActivityThread.java:7796)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:526)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1034)
     Caused by: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.
        at androidx.appcompat.app.AppCompatDelegateImpl.createSubDecor(AppCompatDelegateImpl.java:846)
        at androidx.appcompat.app.AppCompatDelegateImpl.ensureSubDecor(AppCompatDelegateImpl.java:809)
        at androidx.appcompat.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:696)
        at androidx.appcompat.app.AppCompatActivity.setContentView(AppCompatActivity.java:195)
        at com.example.courtcounter.MainActivity.onCreate(MainActivity.java:17)
        at android.app.Activity.performCreate(Activity.java:7868)
        at android.app.Activity.performCreate(Activity.java:7857)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1353)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3496)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3660) 
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2242) 
        at android.os.Handler.dispatchMessage(Handler.java:107) 
        at android.os.Looper.loop(Looper.java:230) 
        at android.app.ActivityThread.main(ActivityThread.java:7796) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:526) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1034) 

这是我的XML代码

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <LinearLayout

        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">


        <LinearLayout
            android:id="@+id/normalButtons"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:orientation="vertical">

            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:fontFamily="sans-serif-light"
                android:gravity="center_horizontal"
                android:padding="16dp"
                android:text="Team A"
                android:textColor="#616161"
                android:textSize="14sp" />

            <TextView
                android:id="@+id/team_a_score"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:fontFamily="sans-serif-light"
                android:gravity="center_horizontal"
                android:paddingBottom="24dp"
                android:text="0"
                android:textColor="#000000"
                android:textSize="56sp" />

            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginLeft="24dp"
                android:layout_marginRight="24dp"
                android:layout_marginBottom="8dp"
                android:onClick="addThreeForTeamA"
                android:text="+3 Points" />

            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginLeft="24dp"
                android:layout_marginRight="24dp"
                android:layout_marginBottom="8dp"
                android:onClick="addTwoForTeamA"
                android:text="+2 Points" />

            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginLeft="24dp"
                android:layout_marginRight="24dp"
                android:layout_marginBottom="8dp"
                android:onClick="addOneForTeamA"
                android:text="Free Throw" />
        </LinearLayout>

        <View
            android:layout_width="1dp"
            android:layout_height="match_parent"
            android:layout_marginTop="16dp"
            android:background="@android:color/darker_gray" />

        <LinearLayout
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:orientation="vertical">

            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:fontFamily="sans-serif-light"
                android:gravity="center_horizontal"
                android:padding="16dp"
                android:text="Team B"
                android:textColor="#616161"
                android:textSize="14sp" />

            <TextView
                android:id="@+id/team_b_score"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:fontFamily="sans-serif-light"
                android:gravity="center_horizontal"
                android:paddingBottom="24dp"
                android:text="0"
                android:textColor="#000000"
                android:textSize="56sp" />

            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginLeft="24dp"
                android:layout_marginRight="24dp"
                android:layout_marginBottom="8dp"
                android:onClick="addThreeForTeamB"
                android:text="+3 Points" />

            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginLeft="24dp"
                android:layout_marginRight="24dp"
                android:layout_marginBottom="8dp"
                android:onClick="addTwoForTeamB"
                android:text="+2 Points" />

            <Button
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginLeft="24dp"
                android:layout_marginRight="24dp"
                android:layout_marginBottom="8dp"
                android:onClick="addOneForTeamB"
                android:text="Free Throw" />
        </LinearLayout>


    </LinearLayout>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginLeft="22dp"
        android:layout_marginRight="22dp"
        android:layout_marginBottom="8dp"
        android:onClick="resetScore"
        android:text="Reset" />
</RelativeLayout>

这是我的Java代码

package com.example.courtcounter;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    int scoreTeamA = 0;
    int scoreTeamB = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

    }

    public void addThreeForTeamA(View view)
    {
        scoreTeamA = scoreTeamA + 3;
        displayForTeamA(scoreTeamA);
    }

    public void addTwoForTeamA(View view)
    {
        scoreTeamA = scoreTeamA + 2;
        displayForTeamA(scoreTeamA);
    }

    public void addOneForTeamA(View view)
    {
        scoreTeamA = scoreTeamA + 1;
        displayForTeamA(scoreTeamA);
    }

    public void addThreeForTeamB(View view)
    {
        scoreTeamB = scoreTeamB + 3;
        displayForTeamB(scoreTeamB);
    }

    public void addTwoForTeamB(View view)
    {
        scoreTeamB = scoreTeamB + 2;
        displayForTeamB(scoreTeamB);
    }

    public void addOneForTeamB(View view)
    {
        scoreTeamB = scoreTeamB + 1;
        displayForTeamB(scoreTeamB);
    }

    public void resetScore(View view)
    {
        scoreTeamA = 0;
        scoreTeamB = 0;
        displayForTeamA(scoreTeamA);
        displayForTeamB(scoreTeamB);
    }

    public void displayForTeamA(int score) {
        TextView scoreView = (TextView) findViewById(R.id.team_a_score);
        scoreView.setText(String.valueOf(score));
    }

    public void displayForTeamB(int score) {
        TextView scoreView = (TextView) findViewById(R.id.team_b_score);
        scoreView.setText(String.valueOf(score));
    }
}

Answer 1

当调试异常时，它通常只是您需要查看的第一个异常；堆栈跟踪中的第一个异常通常会导致其他异常，导致异常瀑布和文本墙。但不要让文字墙恐吓你！

在您的示例中，RuntimeException是由带有以下消息的IllegalStateException引起的

您需要在此活动中使用theme.AppCompat主题（或后代）