(#) Using 'px' dimension !!! WARNING: Using 'px' dimension This is a warning. Id : `PxUsage` Summary : Using 'px' dimension Severity : Warning Category : Correctness Platform : Android Vendor : Android Open Source Project Feedback : https://issuetracker.google.com/issues/new?component=192708 Since : Initial Affects : Resource files Editing : This check runs on the fly in the IDE editor See : https://developer.android.com/guide/practices/screens_support.html#screen-independence 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/PxUsageDetector.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/PxUsageDetectorTest.java) Copyright Year : 2011 For performance reasons and to keep the code simpler, the Android system uses pixels as the standard unit for expressing dimension or coordinate values. That means that the dimensions of a view are always expressed in the code using pixels, but always based on the current screen density. For instance, if `myView.getWidth()` returns 10, the view is 10 pixels wide on the current screen, but on a device with a higher density screen, the value returned might be 15. If you use pixel values in your application code to work with bitmaps that are not pre-scaled for the current screen density, you might need to scale the pixel values that you use in your code to match the un-scaled bitmap source. !!! 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 res/layout/now_playing_after.xml:41:Warning: Avoid using "px" as units; use "dp" instead [PxUsage] android:layout_width="2px" -------------------------- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Here is the source file referenced above: `res/layout/now_playing_after.xml`: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~xml linenumbers <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/now_playing" android:layout_width="fill_parent" android:layout_height="@dimen/now_playing_height" android:orientation="horizontal"> <LinearLayout android:background="@color/background2" android:paddingLeft="14dip" android:paddingRight="14dip" android:paddingTop="10dip" android:paddingBottom="10dip" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1" android:orientation="vertical"> <TextView android:id="@+id/now_playing_title" android:duplicateParentState="true" android:layout_width="fill_parent" android:layout_height="wrap_content" android:textStyle="bold" android:textSize="@dimen/text_size_large" android:textColor="@color/foreground1" android:text="@string/now_playing_after_title" android:maxLines="2" android:ellipsize="end" /> <TextView android:id="@+id/now_playing_subtitle" android:duplicateParentState="true" android:layout_width="fill_parent" android:layout_height="wrap_content" android:paddingTop="3dip" android:textColor="@color/foreground2" android:textSize="@dimen/text_size_small" android:text="@string/now_playing_after_subtitle" android:singleLine="true" android:ellipsize="end" /> </LinearLayout> <View android:layout_width="2px" android:layout_height="fill_parent" android:background="@android:color/white" /> <ImageButton android:background="@drawable/btn_now_playing_more" android:id="@+id/now_playing_more" android:src="@drawable/ic_now_playing_logo" android:padding="12dip" android:layout_width="100mm" android:layout_height="120in" android:onClick="onNowPlayingLogoClick" android:maxHeight="1px" android:scaleType="center" /> </LinearLayout> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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/PxUsageDetectorTest.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, `PxUsageDetector.testPxWarnings`. 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: * Adding the suppression attribute `tools:ignore="PxUsage"` on the problematic XML element (or one of its enclosing elements). You may also need to add the following namespace declaration on the root element in the XML file if it's not already there: `xmlns:tools="http://schemas.android.com/tools"`. ```xml <?xml version="1.0" encoding="UTF-8"?> <resources xmlns:tools="http://schemas.android.com/tools"> ... <style tools:ignore="PxUsage" .../> ... </resources> ``` * 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="PxUsage" 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 'PxUsage' } ``` In Android projects this should be nested inside an `android { }` block. * For manual invocations of `lint`, using the `--ignore` flag: ``` $ lint --ignore PxUsage ...` ``` * Last, but not least, using baselines, as discussed [here](https://googlesamples.github.io/android-custom-lint-rules/usage/baselines.md.html).