My app is showing Runtime Exception when I am trying to run it from Android Studio on my phone

Question

I have given the code below. I have tried many times but it showing 'Runtime Exception' on my phone. And it is showing the below-given error:

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)

Please help me, so that I can run my app.

This is my XML code

<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>

And This is my Java code

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));
    }
}

Post the code of your `Manifest.xml`. – Kamal Nayan Aug 11 '21 at 06:01 — Kamal Nayan, Aug 11 '21 at 06:01

score 0 · Answer 1 · answered Aug 11 '21 at 06:06

When debugging exceptions it is often only the first exception you need to look at; the first exception in the stack-trace often causes the others leading to a waterfall of exceptions and a wall of text. But do not let the wall of text intimidate you!

In your case, the RuntimeException is caused by an IllegalStateException with the message

You need to use a Theme.AppCompat theme (or descendant) with this activity

There are already other questions (with answers!) that could guide you further in how to solve this issue. Here are some of them.

My app is showing Runtime Exception when I am trying to run it from Android Studio on my phone

1 Answers1