(#) Using wrong draw/layout method !!! ERROR: Using wrong draw/layout method This is an error. Id : `WrongCall` Summary : Using wrong draw/layout method Severity : Error 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/WrongCallDetector.java) 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/WrongCallDetectorTest.java) Copyright Year : 2012 Custom views typically need to call `measure()` on their children, not `onMeasure`. Ditto for onDraw, onLayout, etc. !!! 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/LayoutTest.java:23:Error: Suspicious method call; should probably call "layout" rather than "onLayout" [WrongCall] child.onLayout(changed, left, top, right, bottom); // Not OK -------- src/test/pkg/LayoutTest.java:25:Error: Suspicious method call; should probably call "measure" rather than "onMeasure" [WrongCall] super.onMeasure(0, 0); // Not OK --------- src/test/pkg/LayoutTest.java:26:Error: Suspicious method call; should probably call "draw" rather than "onDraw" [WrongCall] super.onDraw(null); // Not OK ------ src/test/pkg/LayoutTest.java:33:Error: Suspicious method call; should probably call "layout" rather than "onLayout" [WrongCall] super.onLayout(false, 0, 0, 0, 0); // Not OK -------- src/test/pkg/LayoutTest.java:34:Error: Suspicious method call; should probably call "measure" rather than "onMeasure" [WrongCall] child.onMeasure(widthMeasureSpec, heightMeasureSpec); // Not OK --------- src/test/pkg/LayoutTest.java:41:Error: Suspicious method call; should probably call "draw" rather than "onDraw" [WrongCall] child.onDraw(canvas); // Not OK ------ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Here are the relevant source files: `res/layout/onclick.xml`: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~xml linenumbers <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" > <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="nonexistent" android:text="Button" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="wrong1" android:text="Button" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="wrong2" android:text="Button" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="wrong3" android:text="Button" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="wrong4" android:text="Button" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="wrong5" android:text="Button" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="wrong6" android:text="Button" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="ok" android:text="Button" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="simple_typo" android:text="Button" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="my\u1234method" android:text="Button" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="wrong7" android:text="Button" /> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="@string/ok" android:text="Button" /> </LinearLayout> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ `src/test/pkg/LayoutTest.java`: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~java linenumbers package test.pkg; import android.content.Context; import android.graphics.Canvas; import android.util.AttributeSet; import android.view.ViewGroup; import android.widget.Button; import android.widget.FrameLayout; import android.widget.LinearLayout; @SuppressWarnings("unused") public class LayoutTest extends LinearLayout { private MyChild child; public LayoutTest(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); } @Override protected void onLayout(boolean changed, int left, int top, int right, int bottom) { super.onLayout(changed, left, top, right, bottom); // OK child.onLayout(changed, left, top, right, bottom); // Not OK super.onMeasure(0, 0); // Not OK super.onDraw(null); // Not OK child.layout(left, top, right, bottom); // OK } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); // OK super.onLayout(false, 0, 0, 0, 0); // Not OK child.onMeasure(widthMeasureSpec, heightMeasureSpec); // Not OK child.measure(widthMeasureSpec, heightMeasureSpec); // OK } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); // OK child.onDraw(canvas); // Not OK child.draw(canvas); // OK } private class MyChild extends FrameLayout { public MyChild(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); } @Override protected void onLayout(boolean changed, int left, int top, int right, int bottom) { super.onLayout(changed, left, top, right, bottom); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); } } } ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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/WrongCallDetectorTest.java) 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, `WrongCallDetector.test`. 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("WrongCall") fun method() { onDraw(...) } ``` or ```java // Java @SuppressWarnings("WrongCall") void method() { onDraw(...); } ``` * Using a suppression comment like this on the line above: ```kt //noinspection WrongCall 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="WrongCall" 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 'WrongCall' } ``` In Android projects this should be nested inside an `android { }` block. * For manual invocations of `lint`, using the `--ignore` flag: ``` $ lint --ignore WrongCall ...` ``` * Last, but not least, using baselines, as discussed [here](https://googlesamples.github.io/android-custom-lint-rules/usage/baselines.md.html).