My app is not working on Marshmallow and below but min sdk is 21. How to resolve?

Question

Min SDK screenshot details:Minsdk is set to 21 & TargetSDK is set to 27

I am a beginner in Android Studio and this is my first app.

Click here for Logcat: Logcat

This is the activity_main.xml

 <?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="wrap_content"
    android:layout_height="match_parent"
    android:background="#ffffff"
    tools:context=".MainActivity"
    tools:layout_editor_absoluteY="25dp"
    tools:layout_width="match_parent">


<ImageButton
    android:id="@+id/cgpa"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentStart="true"
    android:layout_alignParentTop="true"
    android:layout_marginStart="16dp"
    android:layout_marginTop="16dp"
    android:background="#ffffff"
    android:onClick="clickcgpa"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:srcCompat="@drawable/cal"
    android:contentDescription="@string/todo4" />

<ImageButton
    android:id="@+id/cal"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_alignParentStart="true"
    android:background="#ffffff"
    android:onClick="clickcal"
    app:layout_constraintEnd_toStartOf="@+id/club"
    app:layout_constraintStart_toEndOf="@+id/map"
    app:layout_constraintTop_toTopOf="@+id/club"
    app:srcCompat="@drawable/calender"
    android:contentDescription="@string/todo3" />

<ImageButton
    android:id="@+id/map"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentEnd="true"
    android:layout_alignTop="@+id/cgpa"
    android:layout_marginStart="3dp"
    android:background="#ffffff"
    android:onClick="clickmap"
    app:layout_constraintEnd_toStartOf="@+id/calendar"
    app:layout_constraintHorizontal_chainStyle="packed"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="@+id/calendar"
    app:srcCompat="@drawable/marker"
    android:contentDescription="@string/todo1" />

<TextView
    android:id="@+id/textView4"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentStart="true"
    android:layout_below="@+id/cgpa"
    android:layout_marginEnd="9dp"
    android:text="@string/cgpa_calculator"
    android:textAlignment="center"
    android:textStyle="bold"
    app:layout_constraintEnd_toEndOf="@+id/cgpa"
    app:layout_constraintTop_toBottomOf="@+id/cgpa" />

<TextView
    android:id="@+id/textView5"
    android:layout_width="wrap_content"
    android:layout_height="0dp"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:layout_marginStart="16dp"
    android:text="@string/campus_map"
    android:textAlignment="center"
    android:textStyle="bold"
    app:layout_constraintBottom_toBottomOf="@+id/textView6"
    app:layout_constraintStart_toStartOf="@+id/map"
    app:layout_constraintTop_toBottomOf="@+id/map" />

<TextView
    android:id="@+id/textView6"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentEnd="true"
    android:layout_alignParentTop="true"
    android:layout_marginEnd="33dp"
    android:gravity="center_vertical"
    android:text="@string/Main"
    android:textAlignment="center"
    android:textStyle="bold"
    app:layout_constraintEnd_toEndOf="@+id/calendar"
    app:layout_constraintTop_toBottomOf="@+id/calendar" />

<TextView
    android:id="@+id/textView7"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="18dp"
    android:fontFamily="monospace"
    android:text="@string/coming_soon"
    android:textAppearance="@style/TextAppearance.AppCompat.Body2"
    android:textColor="#777777"
    android:textSize="24sp"
    android:textStyle="bold"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/textView4" />

<ImageButton
    android:id="@+id/club"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="234dp"
    android:background="#ffffff"
    android:onClick="clickclub"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toEndOf="@+id/calendar"
    app:layout_constraintTop_toTopOf="parent"
    app:srcCompat="@drawable/people2"
    android:contentDescription="@string/todo2" />

<TextView
    android:id="@+id/textView8"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/club"
    android:textAlignment="center"
    android:textStyle="bold"
    app:layout_constraintEnd_toEndOf="@+id/club"
    app:layout_constraintStart_toStartOf="@+id/club"
    app:layout_constraintTop_toBottomOf="@+id/club" />

  </android.support.constraint.ConstraintLayout>

This is activity_welcome.xml

<?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="#000000"
     tools:context=".Welcome">

<ImageView
    android:id="@+id/imageView5"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginEnd="8dp"
    android:layout_marginRight="8dp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:srcCompat="@drawable/logomain" />
   </android.support.constraint.ConstraintLayout>

And Manifest.xml

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
   package="com.workingbros.ak.assist" android:versionCode="2">

<application
    android:icon="@drawable/logomain1"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".CGPA"></activity>

    <activity android:name=".MainActivity">
    </activity>
    <activity android:name=".Welcome">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>

    </activity>
</application>

</manifest>

Stack Trace:

04-12 23:25:46.153 30277-30277/com.workingbros.ak.assist E/Minikin: addFont failed to create font /system/fonts/NanumGothic.ttf
addFont failed to create font /system/fonts/DroidSansFallback.ttf

04-12 23:25:46.154 30277-30277/com.workingbros.ak.assist E/Minikin: addFont failed to create font /system/fonts/MTLmr3m.ttf

04-12 23:25:46.364 30277-30277/com.workingbros.ak.assist E/AndroidRuntime: FATAL EXCEPTION: main

Process: com.workingbros.ak.assist, PID: 30277

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.workingbros.ak.assist/com.workingbros.ak.assist.MainActivity}: android.view.InflateException: Binary XML file line #13: Binary XML file line #13: Error inflating class ImageButton

 at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2560)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2626)
    at android.app.ActivityThread.-wrap11(ActivityThread.java)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1475)
    at android.os.Handler.dispatchMessage(Handler.java:111)
    at android.os.Looper.loop(Looper.java:207)
    at android.app.ActivityThread.main(ActivityThread.java:5740)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:905)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:766)
 Caused by: android.view.InflateException: Binary XML file line #13: Binary XML file line #13: Error inflating class ImageButton
    at android.view.LayoutInflater.inflate(LayoutInflater.java:539)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:423)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:374)
    at android.support.v7.app.AppCompatDelegateImplV9.setContentView(AppCompatDelegateImplV9.java:287)
    at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:139)
    at com.workingbros.ak.assist.MainActivity.onCreate(MainActivity.java:15)
    at android.app.Activity.performCreate(Activity.java:6543)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1113)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2513)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2626) 
    at android.app.ActivityThread.-wrap11(ActivityThread.java) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1475) 
    at android.os.Handler.dispatchMessage(Handler.java:111) 
    at android.os.Looper.loop(Looper.java:207) 
    at android.app.ActivityThread.main(ActivityThread.java:5740) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:905) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:766) 
 Caused by: android.view.InflateException: Binary XML file line #13: Error inflating class ImageButton
    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:782)
    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:704)
    at android.view.LayoutInflater.rInflate(LayoutInflater.java:835)
    at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:798)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:515)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:423) 
    at android.view.LayoutInflater.inflate(LayoutInflater.java:374) 
    at android.support.v7.app.AppCompatDelegateImplV9.setContentView(AppCompatDelegateImplV9.java:287) 
    at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:139) 
    at com.workingbros.ak.assist.MainActivity.onCreate(MainActivity.java:15) 
    at android.app.Activity.performCreate(Activity.java:6543) 
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1113) 
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2513) 
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2626) 
    at android.app.ActivityThread.-wrap11(ActivityThread.java) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1475) 
    at android.os.Handler.dispatchMessage(Handler.java:111) 
    at android.os.Looper.loop(Looper.java:207) 
    at android.app.ActivityThread.main(ActivityThread.java:5740) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:905) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:766) 
 Caused by: android.content.res.Resources$NotFoundException: Resource ID #0x7f070054
    at android.content.res.Resources.getValue(Resources.java:1552)
    at android.support.v7.widget.AppCompatDrawableManager.loadDrawableFromDelegates(AppCompatDrawableManager.java:328)
    at android.support.v7.widget.AppCompatDrawableManager.getDrawable(AppCompatDrawableManager.java:193)
    at android.support.v7.widget.AppCompatDrawableManager.getDrawable(AppCompatDrawableManager.java:186)
    at android.support.v7.content.res.AppCompatResources.getDrawable(AppCompatResources.java:100)
    at android.support.v7.widget.AppCompatImageHelper.loadFromAttributes(AppCompatImageHelper.java:58)
    at android.support.v7.widget.AppCompatImageButton.<init>(AppCompatImageButton.java:78)
    at android.support.v7.widget.AppCompatImageButton.<init>(AppCompatImageButton.java:68)
    at android.support.v7.app.AppCompatViewInflater.createImageButton(AppCompatViewInflater.java:201)
    at android.support.v7.app.AppCompatViewInflater.createView(AppCompatViewInflater.java:121)
    at android.support.v7.app.AppCompatDelegateImplV9.createView(AppCompatDelegateImplV9.java:1035)
    at android.support.v7.app.AppCompatDelegateImplV9.onCreateView(AppCompatDelegateImplV9.java:1092)
    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:746)
    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:704) 
    at android.view.LayoutInflater.rInflate(LayoutInflater.java:835) 
    at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:798) 
    at android.view.LayoutInflater.inflate(LayoutInflater.java:515) 
    at android.view.LayoutInflater.inflate(LayoutInflater.java:423) 
    at android.view.LayoutInflater.inflate(LayoutInflater.java:374) 
    at android.support.v7.app.AppCompatDelegateImplV9.setContentView(AppCompatDelegateImplV9.java:287) 
    at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:139) 
    at com.workingbros.ak.assist.MainActivity.onCreate(MainActivity.java:15) 
    at android.app.Activity.performCreate(Activity.java:6543) 
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1113) 
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2513) 
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2626) 
    at android.app.ActivityThread.-wrap11(ActivityThread.java) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1475) 
    at android.os.Handler.dispatchMessage(Handler.java:111) 
    at android.os.Looper.loop(Looper.java:207) 
    at android.app.ActivityThread.main(ActivityThread.java:5740) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:905) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:766)

MainActivity.java

package com.workingbros.ak.assist;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle;
import android.view.View;
import android.widget.ImageButton;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
ImageButton cgpa,cal,map,club;
     @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    cgpa= findViewById(R.id.cgpa);
    map=findViewById(R.id.map);
    club=findViewById(R.id.club);
    cal=findViewById(R.id.cal);


}
public void clickcgpa(View v){
    Intent main=new Intent(MainActivity.this,CGPA.class);
    startActivity(main);
}
public void clickmap(View v)
{
    Toast.makeText(this,"Coming Soon",Toast.LENGTH_SHORT).show();
}
public void clickclub(View v)
{
    Toast.makeText(this,"Coming Soon",Toast.LENGTH_SHORT).show();
}
public void clickcal(View v)
    { 
        Toast.makeText(this,"Coming Soon",Toast.LENGTH_SHORT).show();
    }
}

Welcome.java

package com.workingbros.ak.assist;

import android.content.Intent;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Window;
import android.view.WindowManager;


public class Welcome extends AppCompatActivity {
private static int SPLASH_TIME_OUT=1000;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);

    setContentView(R.layout.activity_welcome);

    new Handler().postDelayed(new Runnable(){
        @Override
        public void run(){
            Intent homeIntent=new Intent(Welcome.this,MainActivity.class);
            startActivity(homeIntent);
        finish();
        }
    },SPLASH_TIME_OUT);
}
}

please tell me where is the error?

Compilation error after applying fix:

org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':app:compileDebugJavaWithJavac'.

at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:100)

at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:70)

at org.gradle.api.internal.tasks.execution.OutputDirectoryCreatingTaskExecuter.execute(OutputDirectoryCreatingTaskExecuter.java:51)
at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:62)
at org.gradle.api.internal.tasks.execution.ResolveTaskOutputCachingStateExecuter.execute(ResolveTaskOutputCachingStateExecuter.java:54)
at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:60)
at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:97)
at org.gradle.api.internal.tasks.execution.CleanupStaleOutputsExecuter.execute(CleanupStaleOutputsExecuter.java:87)
at org.gradle.api.internal.tasks.execution.ResolveTaskArtifactStateTaskExecuter.execute(ResolveTaskArtifactStateTaskExecuter.java:52)
at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:52)
at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:54)
at org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter.execute(ExecuteAtMostOnceTaskExecuter.java:43)
at org.gradle.api.internal.tasks.execution.CatchExceptionTaskExecuter.execute(CatchExceptionTaskExecuter.java:34)
at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker$1.run(DefaultTaskGraphExecuter.java:248)
at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:199)
at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:110)
at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:241)
at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:230)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.processTask(DefaultTaskPlanExecutor.java:123)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.access$200(DefaultTaskPlanExecutor.java:79)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker$1.execute(DefaultTaskPlanExecutor.java:104)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker$1.execute(DefaultTaskPlanExecutor.java:98)
at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.execute(DefaultTaskExecutionPlan.java:626)
at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.executeWithTask(DefaultTaskExecutionPlan.java:581)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.run(DefaultTaskPlanExecutor.java:98)
at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:63)
at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:46)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)
at java.lang.Thread.run(Thread.java:745)

Caused by: org.gradle.api.internal.tasks.compile.CompilationFailedException: Compilation failed; see the compiler error output for details.

at org.gradle.api.internal.tasks.compile.JdkJavaCompiler.execute(JdkJavaCompiler.java:50)

at org.gradle.api.internal.tasks.compile.JdkJavaCompiler.execute(JdkJavaCompiler.java:35)
at org.gradle.api.internal.tasks.compile.NormalizingJavaCompiler.delegateAndHandleErrors(NormalizingJavaCompiler.java:98)
at org.gradle.api.internal.tasks.compile.NormalizingJavaCompiler.execute(NormalizingJavaCompiler.java:51)
at org.gradle.api.internal.tasks.compile.NormalizingJavaCompiler.execute(NormalizingJavaCompiler.java:37)
at org.gradle.api.internal.tasks.compile.CleaningJavaCompilerSupport.execute(CleaningJavaCompilerSupport.java:35)
at org.gradle.api.internal.tasks.compile.CleaningJavaCompilerSupport.execute(CleaningJavaCompilerSupport.java:25)
at org.gradle.api.internal.tasks.compile.incremental.IncrementalCompilationFinalizer.execute(IncrementalCompilationFinalizer.java:39)
at org.gradle.api.internal.tasks.compile.incremental.IncrementalCompilationFinalizer.execute(IncrementalCompilationFinalizer.java:24)
at org.gradle.api.tasks.compile.JavaCompile.performCompilation(JavaCompile.java:207)
at org.gradle.api.tasks.compile.JavaCompile.compile(JavaCompile.java:133)
at com.android.build.gradle.tasks.factory.AndroidJavaCompile.compile(AndroidJavaCompile.java:125)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:73)
at org.gradle.api.internal.project.taskfactory.IncrementalTaskAction.doExecute(IncrementalTaskAction.java:46)
at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:39)
at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:26)
at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$1.run(ExecuteActionsTaskExecuter.java:121)
at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:199)
at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:110)
at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeAction(ExecuteActionsTaskExecuter.java:110)
at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:92)
... 32 more

just goto build.gradle(Module: app) and there you will see `minSdkVersion`. Set it to 21 and `targetSdkVersion` is also present there. Set it to 27. — Jaydip Kalkani, Apr 12 '18 at 17:33
update your question with your `build.gradle(Module: app)` file. — Jaydip Kalkani, Apr 12 '18 at 17:37
You should be able to install your app having android version between lolipop and Android p. I think app is installing on your device but crashing at some point. Let me know you can install app on your device or not? — Jaydip Kalkani, Apr 12 '18 at 17:45
you should have to put logcat errors in your question for more details. — Jaydip Kalkani, Apr 12 '18 at 17:47
You main activity layout has an ImageButton which is not able to find a resource. Can you post that layout file please. — Rishabh Jain, Apr 12 '18 at 19:38
If you need screenshots don't add them as comment , it is better to incorporated them into the original question. But use text instead of images whenever possible — Marged, Apr 13 '18 at 12:06
make sure you have image named `cal` inside drawable folder. Let me know if you have it or not? — Jaydip Kalkani, Apr 13 '18 at 12:55
did you have defined `click` method inside your java class for your imageview? and also let me know your app is working on devices having version below marshmallow? — Jaydip Kalkani, Apr 13 '18 at 12:59
Now i can't understand what's the problem. I have one suggestion and may be it will work. try using `src` instead of `srccompat` in imagebutton and if it doesn't work then include your mainactivity.java. May be it can help me to determine actual problem. — Jaydip Kalkani, Apr 13 '18 at 13:08

score 0 · Accepted Answer · edited Jun 20 '20 at 09:12

You have given constraints to map Imagebutton, textView6 TextView and club ImageButton with respect to calender id but as i can see in your activity_main.xml file there is no view having calender id. May be you have it earlier but after that you have changed it to cal id. so, you have to refer your view constraints with respect to cal instead of calender id. Because of wrong id you are getting inflating error.

I have modified your activity_main.xml as below. you can just copy and paste it in your code.

edited activity_main.xml

    <?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="wrap_content"
    android:layout_height="match_parent"
    android:background="#ffffff"
    tools:context=".MainActivity"
    tools:layout_editor_absoluteY="25dp"
    tools:layout_width="match_parent">


    <ImageButton
        android:id="@+id/cgpa"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentStart="true"
        android:layout_alignParentTop="true"
        android:layout_marginStart="16dp"
        android:layout_marginTop="16dp"
        android:background="#ffffff"
        android:onClick="clickcgpa"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="@drawable/cal"
        android:contentDescription="@string/todo4" />

    <ImageButton
        android:id="@+id/cal"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentStart="true"
        android:background="#ffffff"
        android:onClick="clickcal"
        app:layout_constraintEnd_toStartOf="@+id/club"
        app:layout_constraintStart_toEndOf="@+id/map"
        app:layout_constraintTop_toTopOf="@+id/club"
        app:srcCompat="@drawable/calender"
        android:contentDescription="@string/todo3" />

    <ImageButton
        android:id="@+id/map"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:layout_alignTop="@+id/cgpa"
        android:layout_marginStart="3dp"
        android:background="#ffffff"
        android:onClick="clickmap"
        app:layout_constraintEnd_toStartOf="@+id/cal"
        app:layout_constraintHorizontal_chainStyle="packed"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="@+id/cal"
        app:srcCompat="@drawable/marker"
        android:contentDescription="@string/todo1" />

    <TextView
        android:id="@+id/textView4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentStart="true"
        android:layout_below="@+id/cgpa"
        android:layout_marginEnd="9dp"
        android:text="@string/cgpa_calculator"
        android:textAlignment="center"
        android:textStyle="bold"
        app:layout_constraintEnd_toEndOf="@+id/cgpa"
        app:layout_constraintTop_toBottomOf="@+id/cgpa" />

    <TextView
        android:id="@+id/textView5"
        android:layout_width="wrap_content"
        android:layout_height="0dp"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginStart="16dp"
        android:text="@string/campus_map"
        android:textAlignment="center"
        android:textStyle="bold"
        app:layout_constraintBottom_toBottomOf="@+id/textView6"
        app:layout_constraintStart_toStartOf="@+id/map"
        app:layout_constraintTop_toBottomOf="@+id/map" />

    <TextView
        android:id="@+id/textView6"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:layout_alignParentTop="true"
        android:layout_marginEnd="33dp"
        android:gravity="center_vertical"
        android:text="@string/Main"
        android:textAlignment="center"
        android:textStyle="bold"
        app:layout_constraintEnd_toEndOf="@+id/cal"
        app:layout_constraintTop_toBottomOf="@+id/cal" />

    <TextView
        android:id="@+id/textView7"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="18dp"
        android:fontFamily="monospace"
        android:text="@string/coming_soon"
        android:textAppearance="@style/TextAppearance.AppCompat.Body2"
        android:textColor="#777777"
        android:textSize="24sp"
        android:textStyle="bold"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView4" />

    <ImageButton
        android:id="@+id/club"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="234dp"
        android:background="#ffffff"
        android:onClick="clickclub"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@+id/cal"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="@drawable/people2"
        android:contentDescription="@string/todo2" />

    <TextView
        android:id="@+id/textView8"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/club"
        android:textAlignment="center"
        android:textStyle="bold"
        app:layout_constraintEnd_toEndOf="@+id/club"
        app:layout_constraintStart_toStartOf="@+id/club"
        app:layout_constraintTop_toBottomOf="@+id/club" />

</android.support.constraint.ConstraintLayout>

And in future if you want to change any views id then i suggest you to change it from design section because it will ask you a option to change id at all places where you have used it. So, you don't need to update it manually at every place.

UPDATE

As i can see in your project code(Received in private chat) there is some images only in drawable-v24. So, this images are only comfortable with some versions as said here. So, you have to put your images in drawable folder also to make compatible your app in all the versions.

As i can see there is two images cal.png and people2.png in only drawable-v24 and not in drawable folder. so, simple copy and paste them into drawable folder and all will be ok. You can run your project on every devices having versions between your minsdk and targetsdk version.

My app is not working on Marshmallow and below but min sdk is 21. How to resolve?

1 Answers1

UPDATE