I have an existing android application that I'd like to build inside AOSP (android source tree) using Android.mk. The app uses constraint layout which is not included in AOSP source tree (AFAIK). How can I satisfy this dependency? Other support libs are included such as recyclerview, v4 etc but not contraint layout.
Should I download the lib aar and if yes , how do I add/include it? Or should I get the source (where to download?) and build it somewhere in the source tree?
Thanks in advance for any help.
You can create linear layouts now with ConstraintLayout by constraining the sides of each element with each other. The quick way of creating these layouts is to select all the views together and right click to center horizontally or vertically.
Advantages of using ConstraintLayout in AndroidIt helps to improve the UI performance over other layouts. With the help of ConstraintLayout, we can control the group of widgets through a single line of code. With the help of ConstraintLayout, we can easily add animations to the UI components which we used in our app.
Open the layout file (activity_main. xml) in Android Studio and click the Design tab at the bottom of the editor window. In the Component Tree window, right-click LinearLayout and then choose Convert layout to ConstraintLayout from the context menu.
There are several ways to resolve your issue.
1. Add a prebuilt .apk
You don't have to put your source code to the AOSP tree.
You can just add your .apk
file, put it either in packages/apps/YourApp
, or vendor/yourname/packages/apps/YourApp
, or even your_dir_name/packages/apps/YourApp
, and create an Android.mk
file for build system to determine your application.
Android.mk
will look like:
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := YourApplication # your .apk name
LOCAL_SRC_FILES := $(LOCAL_MODULE).apk
LOCAL_MODULE_CLASS := APPS
LOCAL_MODULE_SUFFIX := $(COMMON_ANDROID_PACKAGE_SUFFIX)
include $(BUILD_PREBUILT)
Pros: you can build your project with gradle
.
2. Add source code to AOSP
If you still want to place your source code to packages/apps
and build it there, you can put a ConstrainsLayout
to your project's libs/
directory and add to your Android.mk
something like:
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
# List of static libraries to include in the package
LOCAL_STATIC_JAVA_LIBRARIES := constraint-layout
# Build all java files in the java subdirectory
LOCAL_SRC_FILES := $(call all-subdir-java-files)
# Name of the APK
LOCAL_PACKAGE_NAME := YourApplication
# Tell it to build an APK
include $(BUILD_PACKAGE)
In case you will not get it work (I haven't met this issue, but he did):
LOCAL_STATIC_JAVA_LIBRARIES := libconstraint-layout
include $(BUILD_PACKAGE)
Other stuff, and finally
include $(CLEAR_VARS)
LOCAL_PREBUILT_STATIC_JAVA_LIBRARIES := libconstraint-layout:libs/constraint-layout.aar
Cons: You will have to build your code either with make by mma
or mm -B
, or to have a gradle
as your second build system for development. The second option will work, but to establish a full build and to have your .apk
built in out/
directory you will have to build it with make
.
3. Adding a ConstraintLayout
In case you want to have several applications, which use a constraint layout, you can add it as a new library module as precompiled .aar
.
Can be somewhere in 'vendor/yourname/libs' or 'your_dir_name/libs' respectively.
It is similar to adding a prebuilt .apk
:
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := constraint-layout
LOCAL_SRC_FILES := $(LOCAL_MODULE).aar
LOCAL_MODULE_SUFFIX := .aar
include $(BUILD_PREBUILT)
After that, in your application's Android.mk
you will have to add:
LOCAL_STATIC_JAVA_LIBRARIES := constraint-layout
Alternatively, you can add a ConstraintLayout
's .aar
to the prebuilds/
as it eventually will be there someday.
There is a good topic about Android.mk
: https://wladimir-tm4pda.github.io/porting/build_cookbook.html
https://stackoverflow.com/a/46414919/9237859 is right, except LOCAL_STATIC_JAVA_AAR_LIBRARIES
should be used instead of LOCAL_STATIC_JAVA_LIBRARIES
, since constraint-layout is a aar file.
From Android 9.0, there is no need of adding .aar
and .jar
separately in the project for constraint-layout
. We can use constraint-layout
library built in to AOSP.
We need to add one extra line in Android.mk
:
LOCAL_USE_AAPT2 := true
Then, we need to add:
LOCAL_AAPT_FLAGS := \
--auto-add-overlay \
--extra-packages android.support.constraint
LOCAL_STATIC_ANDROID_LIBRARIES += android-support-constraint-layout
LOCAL_STATIC_JAVA_LIBRARIES += android-support-constraint-layout-solver
For more detailed answer: How to use constraint-layout during AOSP build without including external .aar and .jar
This can be done as follows:
Download constraint-layout.aar and constraint-layout-solve.jar and put these files in lib folder.
Add the following to your Android.mk
file
LOCAL_STATIC_JAVA_AAR_LIBRARIES += constraint-layout
LOCAL_STATIC_JAVA_LIBRARIES += constraint-layout-solver
LOCAL_PREBUILT_STATIC_JAVA_LIBRARIES := constraint-layout:libs/constraint-layout.aar
LOCAL_PREBUILT_STATIC_JAVA_LIBRARIES := constraint-layput-solver:libs/constraint-layout-solver.jar
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