Why Am I Seeing Only Decompiled Source For An Official Android Class?

Please note that I have previously installed Documentation for Android SDK via AS 3.5.2 SDK manager Consider the following inconsistent behavior whilst editing java source code ...

Solution 1:

Determine if the source .jar was shipped with the .aar:

Example: androidx.fragment.app.Fragment Assumes External Library: Gradle: androidx.fragment:fragment:1.1.0@aar

EITHER Right-click the external library (from Project view) --> Library Properties ... OR Navigate to :

.../.gradle/caches/modules-2/files-2.1/androidx.fragment/fragment/1.1.0

Expand the subfolders and confirm something like

b9ebb04df2cb0cad4419af3c658690bc82aa5706/fragment-1.1.0-sources.jar

Example: androidx.constraintlayout.widget.ConstraintLayout Assumes External Library: Gradle: androidx.constraintlayout:constraintlayout:2.0.0-beta3@aar

By using the above method, you will rapidly determine that no sources.jar exists. (You will only see the .aar and the .pom)

Establishing why not is beyond the scope of this question.

Until some-one provides a more satisfactory answer, you may like to try this grubby hack.

Update 21Nov2019: If your problem relates to ConstraintLayout or MotionLayout please star this known issue.