Develop Reference

Android Studio 'findViewById' no longer working

I am very new to Android/Kotlin. I have already created some programs and am making good progress.
But since today I have the problem that I can't get an 'findViewById' running even in the standard 'Hello World' program (Empty Activity).
I have only added the line android:id="#+id/myText" in the XML.
And in MainActivity.kt the line var myTxt = findViewById(android.R.id.myText).
But I get the error message Unresolved reference: 'myText'
The text 'myText' is red.
The usual attempts: Clear Cache, new project, ... I have already tried. The behavior is always the same.
In older projects 'findViewById' is working fine. But I find no difference in Import or settings between working and non working projects.
All in Android Studio 4.1.1
I am grateful for any help
Jan
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<TextView
android:id="#+id/myText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hello World!"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
package com.example.myhelloworld
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.TextView
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
var myTxt = findViewById<TextView>(android.R.id.myText)
}
}

android.R.id.something is only used for android's own internal resources. You should remove that and it will work properly.

In kotlin you dont need to set findViewById instead you can just call the TextView name like this: myText.setText(userNameWithMsg)

android. was the problem! I removed it and all is fine again.
Thank you all! Must be a kind of copy paste error ;-))
Now I can go on .....
Great forum!
Thanks a lot
Jan

Error Integrating Inmobi in Android App

I am integrating inmobi in my android app. I have placed following code in my xml file :-
<com.inmobi.ads.InMobiBanner
android:layout_width="320dp"
android:layout_height="50dp"
android:id="#+id/banner"
ads:placementId="1474202520715"
ads:refreshInterval="60"
/>
I have initialized by main activity as :-
InMobiSdk.init(MainActivity.this, "df19afdaf27f4fb4a2c2b85e2c10bc6a");
InMobiBanner bannerAd =(InMobiBanner) findViewById(R.id.banner);
It is giving me error in placementID and refreshInterval as "No resource identifier found for attribute 'placementId'".
Can any one help me where I am going wrong.

change
xmlns:app="http://schemas.android.com/apk/res-auto"
to
xmlns:app="http://schemas.android.com/apk/lib/com.inmobi.ads.InMobiBanner"

Using Crosswalk in an Android Cordova Project with Embedded WebView

I have an existing Android Cordova project which uses an embedded WebView. What this means is that the Activity does not extend CordovaActivity, but instead embeds the SystemWebView and initializes within the onCreate.
The following is currently how this is being done:
Within the layout XML file
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
.... other layout elements not related to Cordova....
<org.apache.cordova.engine.SystemWebView
android:id="#+id/cdvWebView"
android:layout_width="fill_parent"
android:layout_height="fill_parent" />
</RelativeLayout>
Within the Activity's onCreate:
SystemWebView systemWebView = (SystemWebView) findViewById(R.id.cdvWebView);
CordovaWebView cdvWebView = new CordovaWebViewImpl(new SystemWebViewEngine(systemWebView));
ConfigXmlParser parser = new ConfigXmlParser();
parser.parse(this);
cdvWebView.init(this, parser.getPluginEntries(), parser.getPreferences());
Due to the bug in Lollipop versions 5.0.+ missing the "set" button, I want to implement the Crosswalk plugin into the project.
Unfortunately, all the documentation I'm finding assumes that a typical Cordova install is being used. I haven't been able to get the embedding and initialization of the XWalkWebView working correctly and keep getting a blank white screen.
Has anybody has success with a similar scenario?

I'm not sure, but this might answer your question. It seems to show implementing an XWalkWebView outside of a typical cordova project:
https://github.com/kurli/crosswalk-website/wiki/How-to-use-Crosswalk-Embedded-API-on-Android

MigLayout for design android Forms

I am on a project. My instructor has told me to use MigLayout to design the forms in android. I am finding it difficult to find proper examples and while Using Eclipse for development its showing errors that android perfix is required to use the attributes.
please help me with some examples..
code that i pasted from the source site,mig4android.
<com.saynomoo.mig4android.MigLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
layout_constraints="wrap 4, debug 1"
column_constraints="[]15[75px]25[min]25[]"
row_constraints="[]15"
>
<TextView android:text="label1" component_constraints="skip"/>
<TextView android:text="label2" />
<TextView android:text="label3" component_constraints="wrap"/>
<TextView android:text="label4" />
<TextView android:text="label5" component_constraints="wmin 30"/>
<TextView android:text="label6" component_constraints="wmin 30"/>
<TextView android:text="label7" component_constraints="wmin 30"/>
</com.saynomoo.mig4android.MigLayout>
The component_constraints gave the error

This error means you forget to add android word before any attribute in xml file.
For example-
id="#+id/my_location"
You need to write android before id like below.
android:id="#+id/my_location"
Your code is perfect. But "skip" in component_constraints appears to be ignored. I had to manually add place holder to the layout to "fill in" empty spots. I tried "skip 1" and that also had no impact.
For more information see following link.
Skip as a constraint is not working

Android;Body of ProgressDialog?

I saw this source as layout of AlertDialog in res\layout folder of Android SDK:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout android:id="#+id/body"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:baselineAligned="false"
android:paddingLeft="8dip"
android:paddingTop="10dip"
android:paddingRight="8dip"
android:paddingBottom="10dip">
<ProgressBar android:id="#android:id/progress"
style="#android:style/Widget.ProgressBar"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:max="10000"
android:layout_marginRight="12dip" />
<TextView android:id="#+id/message"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical" />
</LinearLayout>
</FrameLayout>
I tried to find TextView that it's id is "message" like this:
TextView tvMessage = (TextView)dialog.findViewById(android.R.id.message);
It works fine.Then I tried to find LinearLayout that it's id is "body" like this:
LinearLayout body = (LinearLayout)dialog.findViewById(android.R.id.body);
But eclipse show this error:
body cannot be resolved or is not a field
This is snippet code:
ProgressDialog dialog = new ProgressDialog(WriteOpinionActivity.this);
dialog.setMessage("some text");
dialog.show();
TextView tvMessage = (TextView)dialog.findViewById(android.R.id.message);
LinearLayout body = (LinearLayout)dialog.findViewById(android.R.id.body);
Why this error occurs and how I can reach "body"?

Basically, not all resources are accessible to You from platforms res folder.
E.g. I'm able to find #+id/message in global_actions_item.xml, usb_storage_activity.xml, alert_dialog_holo.xml, js_prompt.xml, progress_dialog_holo.xml, progress_dialog.xml, alert_dialog.xml (for API 17), and so, there's no warranty that You get id which defined in progress_dialog.xml (it can be defined in another file and just because of the same name You is able to find it in progress dialog).
Actually, public resources are defined here, however, it looks quite outdated, so some resources might be missed. Checkout these questions about lists of all accessible resources: 1 and 2

Use this instead.
TextView tvMessage = (TextView)dialog.findViewById(R.id.message);
LinearLayout body = (LinearLayout)dialog.findViewById(R.id.body);
You weren't actually using android.R.id.message in the first place. #+id/message means you are creating a new id resource named message.
To use an id that exists in the Android framework, you can see here that you use #android:id/progress. And in source, you use it like you had it: android.R.id.progress.
Otherwise, use android:id="#=id/myIdentifier" in XML and
findViewById(R.id.myIdentifier) in code.
http://developer.android.com/guide/topics/resources/overview.html