cannot resolve symbol 'R' after multiple clean rebuild

Question

Hey guys can can't fix this problem. One day when i open my android studio, it reverted back to the white theme color. Also the tools layout have changed in i didn't even did that because i got a rush project. During that time i didn't notice any changes except for those a mentioned earlier. One day, my coworker asked me to create a simple webview app. That is when i noticed that there is an error and it is the "Cannot resolve symbol 'R'". I tried to clean, rebuild, sync gradle because it is what the answers i found are always telling but it's still the same. Now I created another project and it still has the same problem. The new project's code is below. Please help, thanks.

MainActivity:

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {
    Button btn1, btn2;

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

        //btn1 = (Button)findViewById(R.id.button);
        //btn2 = (Button)findViewById(R.id.button2);
    }
}

layout:

<?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"
    tools:context="app.integritynet.com.egrubweb.MainActivity">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button"
        android:layout_marginLeft="8dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:layout_marginTop="8dp" />

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button"
        app:layout_constraintLeft_toRightOf="@+id/button"
        android:layout_marginLeft="8dp"
        app:layout_constraintTop_toTopOf="@+id/button"
        android:layout_marginTop="0dp" />
</android.support.constraint.ConstraintLayout>

gradle:

apply plugin: 'com.android.application'

android {
    compileSdkVersion 25
    buildToolsVersion "26.0.1"
    defaultConfig {
        applicationId "app.integritynet.com.egrubweb"
        minSdkVersion 16
        targetSdkVersion 25
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support:appcompat-v7:25.3.1'
    compile 'com.android.support.constraint:constraint-layout:1.0.2'
    testCompile 'junit:junit:4.12'
}

manifest:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="app.integritynet.com.egrubweb">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>

gradle project level:

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.3.3'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

UPDATE:

the Messages tab below keeps telling that "Some file crunching failed, see logs for details" then i clicked Show Console Output then clicked on a something like a link which executed something like a clean. Then an error appeared. This is the error:

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:mergeDebugResources'.
> Error: Some file crunching failed, see logs for details

* Try:
Run with --info or --debug option to get more log output.

* Exception is:
org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':app:mergeDebugResources'.
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:84)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:55)
    at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:62)
    at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:58)
    at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:88)
    at org.gradle.api.internal.tasks.execution.ResolveTaskArtifactStateTaskExecuter.execute(ResolveTaskArtifactStateTaskExecuter.java:46)
    at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:51)
    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$1.execute(DefaultTaskGraphExecuter.java:236)
    at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker$1.execute(DefaultTaskGraphExecuter.java:228)
    at org.gradle.internal.Transformers$4.transform(Transformers.java:169)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:106)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:61)
    at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:228)
    at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:215)
    at org.gradle.execution.taskgraph.AbstractTaskPlanExecutor$TaskExecutorWorker.processTask(AbstractTaskPlanExecutor.java:77)
    at org.gradle.execution.taskgraph.AbstractTaskPlanExecutor$TaskExecutorWorker.run(AbstractTaskPlanExecutor.java:58)
    at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor.process(DefaultTaskPlanExecutor.java:32)
    at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter.execute(DefaultTaskGraphExecuter.java:113)
    at org.gradle.execution.SelectedTaskExecutionAction.execute(SelectedTaskExecutionAction.java:37)
    at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:37)
    at org.gradle.execution.DefaultBuildExecuter.access$000(DefaultBuildExecuter.java:23)
    at org.gradle.execution.DefaultBuildExecuter$1.proceed(DefaultBuildExecuter.java:43)
    at org.gradle.execution.DryRunBuildExecutionAction.execute(DryRunBuildExecutionAction.java:32)
    at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:37)
    at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:30)
    at org.gradle.initialization.DefaultGradleLauncher$3.execute(DefaultGradleLauncher.java:196)
    at org.gradle.initialization.DefaultGradleLauncher$3.execute(DefaultGradleLauncher.java:193)
    at org.gradle.internal.Transformers$4.transform(Transformers.java:169)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:106)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:56)
    at org.gradle.initialization.DefaultGradleLauncher.doBuildStages(DefaultGradleLauncher.java:193)
    at org.gradle.initialization.DefaultGradleLauncher.doBuild(DefaultGradleLauncher.java:119)
    at org.gradle.initialization.DefaultGradleLauncher.run(DefaultGradleLauncher.java:102)
    at org.gradle.launcher.exec.GradleBuildController.run(GradleBuildController.java:71)
    at org.gradle.tooling.internal.provider.runner.BuildModelActionRunner.run(BuildModelActionRunner.java:50)
    at org.gradle.launcher.exec.ChainingBuildActionRunner.run(ChainingBuildActionRunner.java:35)
    at org.gradle.tooling.internal.provider.runner.RunAsBuildOperationBuildActionRunner$1.execute(RunAsBuildOperationBuildActionRunner.java:43)
    at org.gradle.tooling.internal.provider.runner.RunAsBuildOperationBuildActionRunner$1.execute(RunAsBuildOperationBuildActionRunner.java:40)
    at org.gradle.internal.Transformers$4.transform(Transformers.java:169)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:106)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:56)
    at org.gradle.tooling.internal.provider.runner.RunAsBuildOperationBuildActionRunner.run(RunAsBuildOperationBuildActionRunner.java:40)
    at org.gradle.tooling.internal.provider.runner.SubscribableBuildActionRunner.run(SubscribableBuildActionRunner.java:75)
    at org.gradle.launcher.exec.ChainingBuildActionRunner.run(ChainingBuildActionRunner.java:35)
    at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:41)
    at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:26)
    at org.gradle.tooling.internal.provider.ContinuousBuildActionExecuter.execute(ContinuousBuildActionExecuter.java:75)
    at org.gradle.tooling.internal.provider.ContinuousBuildActionExecuter.execute(ContinuousBuildActionExecuter.java:49)
    at org.gradle.tooling.internal.provider.ServicesSetupBuildActionExecuter.execute(ServicesSetupBuildActionExecuter.java:44)
    at org.gradle.tooling.internal.provider.ServicesSetupBuildActionExecuter.execute(ServicesSetupBuildActionExecuter.java:29)
    at org.gradle.launcher.daemon.server.exec.ExecuteBuild.doBuild(ExecuteBuild.java:67)
    at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:36)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:120)
    at org.gradle.launcher.daemon.server.exec.WatchForDisconnection.execute(WatchForDisconnection.java:47)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:120)
    at org.gradle.launcher.daemon.server.exec.ResetDeprecationLogger.execute(ResetDeprecationLogger.java:26)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:120)
    at org.gradle.launcher.daemon.server.exec.RequestStopIfSingleUsedDaemon.execute(RequestStopIfSingleUsedDaemon.java:34)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:120)
    at org.gradle.launcher.daemon.server.exec.ForwardClientInput$2.call(ForwardClientInput.java:74)
    at org.gradle.launcher.daemon.server.exec.ForwardClientInput$2.call(ForwardClientInput.java:72)
    at org.gradle.util.Swapper.swap(Swapper.java:38)
    at org.gradle.launcher.daemon.server.exec.ForwardClientInput.execute(ForwardClientInput.java:72)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:120)
    at org.gradle.launcher.daemon.server.exec.LogAndCheckHealth.execute(LogAndCheckHealth.java:55)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:120)
    at org.gradle.launcher.daemon.server.exec.LogToClient.doBuild(LogToClient.java:60)
    at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:36)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:120)
    at org.gradle.launcher.daemon.server.exec.EstablishBuildEnvironment.doBuild(EstablishBuildEnvironment.java:72)
    at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:36)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:120)
    at org.gradle.launcher.daemon.server.exec.StartBuildOrRespondWithBusy$1.run(StartBuildOrRespondWithBusy.java:50)
    at org.gradle.launcher.daemon.server.DaemonStateCoordinator$1.run(DaemonStateCoordinator.java:297)
    at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:54)
    at org.gradle.internal.concurrent.StoppableExecutorImpl$1.run(StoppableExecutorImpl.java:40)
Caused by: com.android.build.gradle.tasks.ResourceException: Error: Some file crunching failed, see logs for details
    at com.android.build.gradle.tasks.MergeResources.doFullTaskAction(MergeResources.java:166)
    at com.android.build.gradle.internal.tasks.IncrementalTask.taskAction(IncrementalTask.java:88)
    at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:73)
    at org.gradle.api.internal.project.taskfactory.DefaultTaskClassInfoStore$IncrementalTaskAction.doExecute(DefaultTaskClassInfoStore.java:163)
    at org.gradle.api.internal.project.taskfactory.DefaultTaskClassInfoStore$StandardTaskAction.execute(DefaultTaskClassInfoStore.java:134)
    at org.gradle.api.internal.project.taskfactory.DefaultTaskClassInfoStore$StandardTaskAction.execute(DefaultTaskClassInfoStore.java:123)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeAction(ExecuteActionsTaskExecuter.java:95)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:76)
    ... 78 more
Caused by: Error: Some file crunching failed, see logs for details
    at com.android.ide.common.res2.MergedResourceWriter.end(MergedResourceWriter.java:272)
    at com.android.ide.common.res2.DataMerger.mergeData(DataMerger.java:301)
    at com.android.ide.common.res2.ResourceMerger.mergeData(ResourceMerger.java:410)
    at com.android.build.gradle.tasks.MergeResources.doFullTaskAction(MergeResources.java:159)
    ... 85 more
Caused by: java.lang.RuntimeException: Some file crunching failed, see logs for details
    at com.android.builder.png.QueuedCruncher.waitForAll(QueuedCruncher.java:293)
    at com.android.builder.png.QueuedCruncher.end(QueuedCruncher.java:314)
    at com.android.builder.internal.aapt.v1.AaptV1.end(AaptV1.java:375)
    at com.android.ide.common.res2.MergedResourceWriter.end(MergedResourceWriter.java:269)
    ... 88 more

Possible duplicate of [R cannot be resolved - Android error](https://stackoverflow.com/questions/885009/r-cannot-be-resolved-android-error) — chirag90, Aug 22 '17 at 08:02
Add `import app.integritynet.com.egrubweb.R` if your Activity is in a different package. — Bob, Aug 22 '17 at 08:23
@RickyManalo do one thing just try and delete your .gradle file from your project folder and restart the android studios — Snehal Gongle, Aug 22 '17 at 08:28
look in your project folder there will be a folder .gradle and not the gradle one, dot is imp "." which you have to delete — Snehal Gongle, Aug 22 '17 at 08:36
do i delete the whole folder or a specific file only coz you said i need to delete a gradle file — Ricky Manalo, Aug 22 '17 at 08:40
Hey try File then Invalidate cache/Restart if it still doesn't work! Then I am doubting the build version in the app/build.gradle why is it 26? Support is 25, target 25,compile is 25! I am not sure about that because in my projects it is also 25 like the rest! Has it worked before? — Xenolion, Aug 22 '17 at 08:43
just did that invalidate cache/restart and android studio is currently building. yeah it worked before. if that is the reason then my question isn't a duplicate. i hate it when someone just straight up flag my question as duplicate. — Ricky Manalo, Aug 22 '17 at 08:51
@Xenolion it does not work, i also change 25 to 23 because my last project used that then did clean, rebuild, sync but still no luck — Ricky Manalo, Aug 22 '17 at 09:02
Are you importing the proper R file for the same project??? Please check that your R file is for the same project that you are using in your import statements — Snehal Gongle, Aug 22 '17 at 09:15
i'm not importing anything. what i posted above is the fresh files, i didn't add or changed anything on those files except for the MainActivity.java — Ricky Manalo, Aug 22 '17 at 09:21
i've updated my post. i've added an error that i guess is the reason of the problem — Ricky Manalo, Aug 22 '17 at 09:22
@RickyManalo i'm not too sure about this now but according to your logcat i would suggest you do something related in these answers https://stackoverflow.com/questions/36495978/some-file-crunching-failed-see-logs-for-details — Snehal Gongle, Aug 22 '17 at 09:33
no @SnehalGongle, i just found out the reason the only thing i can say is Android Studio f*cked itself. After i looked at the error at console again, i searched about the error in it which is Android Studio AAPT err: libpng error: Not a PNG file. also saw something like your link. then i go to the mipmap folders and noticed that the ic_launcher images didn't have a preview. long story short i removed the the android:roundIcon tag in the manifest, removed the ic_launcher images and now its working — Ricky Manalo, Aug 22 '17 at 09:45
thanks @SnehalGongle and to all of you who helped me. thanks a lot guys — Ricky Manalo, Aug 22 '17 at 09:48

score 1 · Answer 1 · answered Aug 25 '17 at 10:49

4th and 9th line in your app gradle file: change the 'compileSdkVersion' and 'targetSdkVersion' to 26. Or (next line) change the 'buildToolsVersion' to "25.X.X"

The reason for this is that gradle is building your project for version 26 and compiling at version 25. This was probably caused when you reverted, and the gradle buildToolsVersion stayed/changed to the latest version.

Hope this helps.

score 0 · Answer 2 · answered Aug 22 '17 at 08:32

0

you try File -> Invalidate Caches/Restart...

answered Aug 22 '17 at 08:32

Nasimxon

132
1
7

cannot resolve symbol 'R' after multiple clean rebuild

2 Answers2