---
slug: "flutter=build-apk-Gradle-task-assembleRelease-failed-with-exit-code-1"
title: "When Running `flutter build apk`, Gradle Task `assembleRelease` Failed with Exit Code 1 and APK is Not Created"
description: "Change a DRF (Django REST framework) serializer's datetime output format away from ISO — use `format=` or override `to_representation`."
url: "https://www.ytyng.com/en/blog/flutter=build-apk-Gradle-task-assembleRelease-failed-with-exit-code-1"
publish_date: "2019-09-13T10:45:51Z"
created: "2019-09-13T10:45:51Z"
updated: "2026-05-11T13:21:41.830Z"
categories: ["Android"]
keywords: ""
featured_image_url: "https://media.ytyng.com/resize/20260124/46e797965c7c4b9cb1009a1f1c223485.png.webp?width=768"
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lang: "en"
---

# When Running `flutter build apk`, Gradle Task `assembleRelease` Failed with Exit Code 1 and APK is Not Created

<p>While developing an app with Flutter, there are no issues when debugging with Android Studio.</p>
<p>However, when running <code>flutter build apk</code>,</p>
<p></p>
<pre>Gradle task assembleRelease failed with exit code 1</pre>
<p></p>
<p>is displayed and no APK is created.</p>
<p></p>
<p>Referencing this StackOverflow article:</p>
<p></p>
<p><a href="https://stackoverflow.com/questions/55750890/flutter-failed-to-compile-apk-finished-with-error-gradle-task-assembledebug-fa">https://stackoverflow.com/questions/55750890/flutter-failed-to-compile-apk-finished-with-error-gradle-task-assembledebug-fa</a></p>
<p>Based on the steps outlined:</p>
<p></p>
<p>1. Open <code>gradle-wrapper.properties</code>,</p>
<pre><span>distributionUrl=https\://services.gradle.org/distributions/gradle-5.5-all.zip</span></pre>
<p>and change</p>
<pre><span>distributionUrl</span><span>=</span><span>https</span>\:<span>//services.gradle.org/distributions/gradle-4.10.2-all.zip<br /></span></pre>
<p>(downgrade)</p>
<p></p>
<p>2. Open <code>build.gradle</code></p>
<pre>dependencies <span>{<br /></span><span>    </span><span>classpath 'com.android.tools.build:gradle:3.6.0-alpha09'<br /></span><span></span></pre>
<p>and change</p>
<pre>dependencies <span>{<br /></span><span>    </span>classpath <span>'com.android.tools.build:gradle:3.3.2'</span></pre>
<p></p>
<p>3. Run <code>flutter clean</code> and then re-run <code>flutter build apk</code>.</p>
<p></p>
<p>By doing this, you will be able to <strong>see the cause of the error</strong>.</p>
<p></p>
<p>In my case, the issue was due to using a library that was not compatible with AndroidX. I opened <code>pubspec.yaml</code> and upgraded to a compatible version to resolve the issue.</p>
<p></p>
<p>Once the problem is resolved, you can revert the downgraded changes mentioned above.</p>
<p></p>