(#) Toast created but not shown !!! WARNING: Toast created but not shown This is a warning. Id : `ShowToast` Summary : Toast created but not shown Severity : Warning Category : Correctness Platform : Android Vendor : Android Open Source Project Feedback : https://issuetracker.google.com/issues/new?component=192708 Since : Initial Affects : Kotlin and Java files Editing : This check runs on the fly in the IDE editor Implementation : [Source Code](https://cs.android.com/android-studio/platform/tools/base/+/mirror-goog-studio-main:lint/libs/lint-checks/src/main/java/com/android/tools/lint/checks/ToastDetector.kt) Tests : [Source Code](https://cs.android.com/android-studio/platform/tools/base/+/mirror-goog-studio-main:lint/libs/lint-tests/src/test/java/com/android/tools/lint/checks/ToastDetectorTest.kt) Copyright Year : 2012 `Toast.makeText()` creates a `Toast` but does **not** show it. You must call `show()` on the resulting object to actually make the `Toast` appear. !!! Tip This lint check has an associated quickfix available in the IDE. (##) Example Here is an example of lint warnings produced by this check: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~text src/test/pkg/ToastTest.java:32:Warning: Toast created but not shown: did you forget to call show()? [ShowToast] Toast.makeText(context, "foo", Toast.LENGTH_LONG); -------------- src/test/pkg/ToastTest.java:33:Warning: Toast created but not shown: did you forget to call show()? [ShowToast] Toast toast = Toast.makeText(context, R.string.app_name, 5000); -------------- src/test/pkg/ToastTest.java:39:Warning: Toast created but not shown: did you forget to call show()? [ShowToast] Toast.makeText(context, "foo", Toast.LENGTH_LONG); -------------- src/test/pkg/ToastTest.java:54:Warning: Toast created but not shown: did you forget to call show()? [ShowToast] Toast toast2 = Toast.makeText(context, "foo", Toast.LENGTH_LONG); // not shown -------------- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Here is the source file referenced above: `src/test/pkg/ToastTest.java`: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~java linenumbers package test.pkg; import android.app.Activity; import android.content.Context; import android.os.Bundle; import android.widget.Toast; @SuppressWarnings("ClassNameDiffersFromFileName") public abstract class ToastTest extends Context { private Toast createToast(Context context) { // Don't warn here return Toast.makeText(context, "foo", Toast.LENGTH_LONG); } private void showToast(Context context) { // Don't warn here Toast toast = Toast.makeText(context, "foo", Toast.LENGTH_LONG); System.out.println("Other intermediate code here"); int temp = 5 + 2; toast.show(); } private void showToast2(Context context) { // Don't warn here int duration = Toast.LENGTH_LONG; Toast.makeText(context, "foo", Toast.LENGTH_LONG).show(); Toast.makeText(context, R.string.app_name, duration).show(); } private void broken(Context context) { // Errors Toast.makeText(context, "foo", Toast.LENGTH_LONG); Toast toast = Toast.makeText(context, R.string.app_name, 5000); toast.getDuration(); } // Constructor test public ToastTest(Context context) { Toast.makeText(context, "foo", Toast.LENGTH_LONG); } @android.annotation.SuppressLint("ShowToast") private void checkSuppress1(Context context) { Toast toast = Toast.makeText(this, "MyToast", Toast.LENGTH_LONG); } private void checkSuppress2(Context context) { @android.annotation.SuppressLint("ShowToast") Toast toast = Toast.makeText(this, "MyToast", Toast.LENGTH_LONG); } private void showToastWrongInstance(Context context) { Toast toast1 = Toast.makeText(context, "foo", Toast.LENGTH_LONG); // OK Toast toast2 = Toast.makeText(context, "foo", Toast.LENGTH_LONG); // not shown toast1.show(); } public static final class R { public static final class string { public static final int app_name = 0x7f0a0000; } } } ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ You can also visit the [source code](https://cs.android.com/android-studio/platform/tools/base/+/mirror-goog-studio-main:lint/libs/lint-tests/src/test/java/com/android/tools/lint/checks/ToastDetectorTest.kt) for the unit tests for this check to see additional scenarios. The above example was automatically extracted from the first unit test found for this lint check, `ToastDetector.testJava`. To report a problem with this extracted sample, visit https://issuetracker.google.com/issues/new?component=192708. (##) Suppressing You can suppress false positives using one of the following mechanisms: * Using a suppression annotation like this on the enclosing element: ```kt // Kotlin @Suppress("ShowToast") fun method() { makeText(...) } ``` or ```java // Java @SuppressWarnings("ShowToast") void method() { makeText(...); } ``` * Using a suppression comment like this on the line above: ```kt //noinspection ShowToast problematicStatement() ``` * Using a special `lint.xml` file in the source tree which turns off the check in that folder and any sub folder. A simple file might look like this: ```xml <?xml version="1.0" encoding="UTF-8"?> <lint> <issue id="ShowToast" severity="ignore" /> </lint> ``` Instead of `ignore` you can also change the severity here, for example from `error` to `warning`. You can find additional documentation on how to filter issues by path, regular expression and so on [here](https://googlesamples.github.io/android-custom-lint-rules/usage/lintxml.md.html). * In Gradle projects, using the DSL syntax to configure lint. For example, you can use something like ```gradle lintOptions { disable 'ShowToast' } ``` In Android projects this should be nested inside an `android { }` block. * For manual invocations of `lint`, using the `--ignore` flag: ``` $ lint --ignore ShowToast ...` ``` * Last, but not least, using baselines, as discussed [here](https://googlesamples.github.io/android-custom-lint-rules/usage/baselines.md.html).