Android Nullpointerexception thrown when R.id value not found - android

When I add a new activity (.java and .XML files) in my Android Project some R.id values that used to work get lost and causes my App to throw a NullPointerException, but if I use the hex value it works again:
R.java: public static final int editTextTotal=0x7f040064;
findViewById(R.id.editTextTotal); //Throws nullpointerex after I add a new activity.
findViewById(0x7f040067) //Works
I got tired of Eclipse so I'm working with commands only, is there anything else that should be done other than add the files, change the manifest and run the "ant debug" command to add new activities?

What is the import your are using? You have to use
your_package_name.R

There is something wrong with your ADT. Try to update to the latest version.
If the problem still exists, try to clean the project whenever you add a new xml.

Related

Android databinding build error: constant expression required

I am writing Android application using DataBinding by referencing https://developer.android.com/topic/libraries/data-binding/index.html.
But while building my project, It is showing an error in generated class as
> '/databinding/DataBinderMapper.java:10: error: constant expression
> required.'
This error is happening in switch statement inside generated class DataBinderMapper.java (This file is an auto generated file for databinding)
Any one knows the reason for this java switch case error happening in Auto generated buld file?
Edits:
I found the reason for this issue is, layout reference created in R.java file is not final for this case.
For example, in my case layout reference in R.java is
public static int activity_main=0x7f04001c;
Actually it should be
public static final int activity_main=0x7f04001b;
But I don't know the reason for this happened and how to change it to final.
Probably your model that you are binding against has final modifiers in its variables.
This error happens when your project has dependency with library or external plugin apart from application.
The reason for this issue is, the ids generated might clash when you have dependency with multiple library/ plugins.

AndroidStudio was not right after change code

Situation:
I use Android studio, when i change a line of code in it sometimes it was wrong, the code i just change is not work it still run my old version code.
such as
int a = 1;//old version
int a = 2;//new version
sometimes a still value 1 when i run the new version code.
fix:
I know i can clean the project and restart Android Studio to fix it, but why it's happened?
My Question:
It's just a AS bug or something i was wrong in my project setting?
For more detail example:
I have class a with the method putLog() like below
private void putLog()
{
Log.i("tag","string");
}
Then i find i don't need the Log.i("tag","string") anymore, so i delete it
private void putLog()
{
// Log.i("tag","string");
}
but after i delete it, the log output is still there, my delete is not work.
I restart Android Studio and clean the cache, the log is not show anymore.
That's mainly because i have use multiple-channel gradle script to generate apk, now i remove it, it not show again.

Android Databinding : package does not exist

I'm trying to use data-binding with Android.
I can not anymore build my project. I got this error :
"Error:(13, 46) error: package ch.company.project.databinding does not
exist"
Here my gradle :
http://pastebin.com/dkXd1Mxr
and
http://pastebin.com/n9hkFWGQ
And here the gradle output :
https://pastebin.com/w93Rausg
Thanks to Yigit!
The issue was not directly link to Android Databinding.
There were a bug in the project (some variables not correctly setted)
I would recommend to use gradle with "--debug and --stacktrace" for more informations, it's helping a lot.
earlier my package name was "com.xyz.abc.Models"
changing the package name to all small letters "Models" -> "models"
solved the issue.
The bug is not the DataBinding Package, it's a syntactic or logical error. For example, you have the attribute "lastName" in your POJO, but in the layout it's android:text="#{user.lastname}".
Check your "layout" and do Rebuild Project.
I am not satisfied with accepted answer, that tell you to stack trace without hints.
Here are some possible causes that lead to this problem. Check if you are not doing any of the following.
Basically Android DataBinding is not that mature still. It will fail without appropriate errors many times.
So if you have an issue like package ch.company.project.databinding does not exist".
Possible causes of fail:
First of all check your recently edited layouts xml one by one for errors (for wrong imports & variables). I don't get proper error in this case usually.
Check your data binding syntax in binding block ({...}) in layout element for errors. Always Rebuild (not Build) project after working in one layout.
Check your #BindingAdapter method having correct parameters. For example imageUrl binding adapter would accept ImageView or View as first parameter.
You should always Rebuild project after doing work in one layout.
If you are not able to find errors by above steps, then try --debug and --stacktrace in compile option of
File> Settings> Build, Execution, Deployment> Compiler> Command-line Options
Make sure your package name start with lowercase letter.
in my case issue solved after two hours of struggle
Package name should start with small letter.
for example Activities is wrong it'll give an error instead refactor->rename to activities
I got the error:
Error:(9, 46) error: package com.company.www.bar.databinding does not
exist.
i just remove "=" sign . it worked for me
From this :
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:onClick="#={()->activity.onButtonClick()}"/>
to :
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:onClick="#{()->activity.onButtonClick()}"/>
I had similar problems with my project
You could try:
check xml files for errors that cause a build failure
clean project
File -- invalidate caches / restart
On my particular case, I was using Dagger 2. This package error appears in a lot of classes without any relation with the original error: a dependency injection error.
Happy reminder: Scroll more on your stacktrace to know what is the real problem.
I was stuck with same error for hours. After trying several solution from stackoverflow, I updated my project with stable gradle dependencies.
Still it was not solved, however with the same gradle dependency DataBinding was working fine in another project of mine.
So, I went project folder using explorer and Deleted 2 things.
build folder
all files from .idea/libraries
After that i synced the project and it continued to work just fine.
Package names have to START with Small Letters. Otherwise, Binding library cannot understand that is it class or package. Moreover, you do NOT need to do all of it with small letters.
Example, wrong usage:
package com.thecompany.activity.ContactInfo; //Problem is ContactInfo, 'C'.
Example, TRUE usage:
package com.thecompany.activity.contactInfo; //Solution is contactInfo, 'c'.
Make sure your model's fields you reference in layout have public access modifiers
Change
{ databinding = true}
to
buildFeatures{
dataBinding = true
}
If you're coming to this question because you switched to JDK11 in Android Studio Artic Fox and your view binding broke in the UI but not during execution then be aware that this is a known issue and should be resolved in Bumble Bee:
https://issuetracker.google.com/issues/180946610
The current fix is to switch back to JDK8 (or install the Bumble Bee canary release).
To get rid of this error just enclose your complete layout design inside a plain layout tag in the activity_main.xml file.
After wasting many hours in finding solution this worked for me. Give it a try.
if you tried this steps
invalidate/restart`
keeping this properties in gradel.properties
android.databinding.enableV2=false
android.enableExperimentalFeatureDatabinding=true
and checking all xml files looks good.
then you should go with this solution, add below code in project level build.gradle
allprojects {
gradle.projectsEvaluated {
tasks.withType(JavaCompile) {
options.compilerArgs << "-Xmaxerrs" << "1000"
}
}
}
this will give you exact error where you have actual error
explanation: above code will increase the size of the compile error
in my case, i follow the android documentation :
buildFeatures {
viewBinding true
}
use "=" instead of space
buildFeatures {
viewBinding = true
}
Try following Refactor -> migrate to androidx
and in the build.grade(:app)
implementation 'androidx.appcompat:appcompat:1.0.0'
or use new version is released
implementation 'androidx.databinding:databinding-runtime:4.1.0'
Make sure that if your layout filename is named in the following format: <name>_activity.xml that your binding class name complies the following format as well: <name>ActivityBinding
For me, changing my layout filename from activity_login.xml to login_activity.xml resolved this issue because my binding class name was LoginActivityBinding.
Here's an except from the Android Layouts and binding expressions page mentioning this:
A binding class is generated for each layout file. By default, the name of the class is based on the name of the layout file, converting it to Pascal case and adding the Binding suffix to it. The above layout filename is activity_main.xml so the corresponding generated class is ActivityMainBinding
if you use a model in your layout, make sure you dont have the model and the package named same and also the paackage name should start with small letter.
i changed mine from Model>Model.class to modelPac>Model.class
In my case the problem appeared when I was creating productFlavors and set sourceSets.
Changing
sourceSets {
develop {
res.srcDirs = ['myApp/src/develop/res']
}
to
sourceSets {
develop {
res.srcDirs = ['src/develop/res']
}
}
solved my issue.

Unable to run Bitmap sample code for Android

I am trying to run the sample from :
http://developer.android.com/training/displaying-bitmaps/display-bitmap.html
However I encountered lots of errors like:
Description Resource Path Location Type
BuildConfig cannot be resolved to a variable ImageGridFragment.java /ImageGridActivity/src/com/example/android/bitmapfun/ui line 124 Java Problem
Description Resource Path Location Type
SuppressLint cannot be resolved to a type Utils.java /ImageGridActivity/src/com/example/android/bitmapfun/util line 99 Java Problem
I ran thru Google but could get nothing. Adjusted the android build target to 4.0.3 (15) but still no clue. Anyone ran this sample successfully?
Thanks.
Here is my solution:
1.Create a new class:
package com.example.android.bitmapfun;
public class BuildConfig {
public static final boolean DEBUG = true;
}
2.Comment the lines that contain "SuppressLint":
//import android.annotation.SuppressLint;
// #SuppressLint("NewApi")
Android developer tools r17 brings a feature to Eclipse where a class is auto built at build-time, called BuildConfig, which contains a constant that can be used by the app developer to sense whether the build is a dev build or a production build. This feature appears to be in the Eclipse integration support, so when using IntelliJ, this useful feature is not available
In gen folder with R.java there should be BuildConfig.java if your program compiled successfully.
/** Automatically generated file. DO NOT MODIFY */
package com.example.android.bitmapfun;
public final class BuildConfig {
public final static boolean DEBUG = true;
}
Clean your project and try to launch it again.
It worked for me.
For me also it is not running directly import to eclipse. Just i put comments which lines is showing errors then it is working fine for me. May be it is not a right answer but we can see the application functionality by running the code so i did like that.

Android Annotations framework doesn't seem to generate anything

I'm trying to use Android annotations framework because it seems quite powerful. I'm quite stuck to configuring my first project based on it.
I followed every step of the wiki but it doesn't generate any file after a build.
So when I ask for a generated class from the manifest:
<activity android:name=".MyActivity_"
android:label="#string/app_name">
I get an exception:
java.lang.ClassNotFoundException
My activity is exactly the same one as in the wiki:
#EActivity(R.layout.main)
public class MyActivity extends Activity {
#ViewById
EditText myInput;
#ViewById(R.id.myTextView)
TextView textView;
#Click
void myButton() {
String name = myInput.getText().toString();
textView.setText("Hello "+name);
}
}
Any ideas?
EDIT: Just found out a directory ".apt_generated" is made but it's empty after the build.
This seems to be an AndroidAnnotations bug, and should be reported on the dedicated bug tracker, here : http://code.google.com/p/androidannotations/issues/entry . You could also use the AndroidAnnotations mailing list, http://groups.google.com/group/androidannotations
First, I have a few questions :
Which IDE do you use : Eclipse, Netbeans, IntelliJ ? Which version ?
Do you use Maven, Ant, or only your IDE to build the project ?
Your problem may be due to a few things : annotation processing not triggered, a bug in AA, or the files generated in a folder not part of the classpath.
In Eclipse, you may get more information from the "Window > Show View > Error Log" view. If annotation processing is triggered, you should see some messages about AndroidAnnotations.
For other people who are running into this and the leading answer doesn't work, run a build and then search for the file androidannotations.log somewhere in the project. This log file is generated and may hint at what is wrong.
For me, it had a warning message that it could not locate AndroidManifest.xml. Though this seemed like just a warning, it was actually the cause of the error... Not finding my AndroidManifest.xml file resulted in it not generating some of the classes it should have.
Check if you have the xml file. If not, the solution is obvious. If you do have it, the typical reason AA cannot find the file is because it is in a non-standard location -- AA recursively checks the parent directories above where it generates files for this xml file and will fail if it's not there. In my case, my AndroidManifest.xml was located in [project root]/app/src/main which is not a direct ancestor folder so that was the problem.
You can specify where your xml file is in your project build.gradle:
android {
defaultConfig {
javaCompileOptions {
annotationProcessorOptions {
arguments = ["androidManifestFile": "specify_location_of_AndroidManifest.xml_here"]
}
}
}
}

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