Develop Reference

Trouble with ID in AIDE

I'm writing a simple Android App using AIDE (Android IDE). I gave one of my layout elements an ID, but when I try to access the element using findViewById(), I get an error tht says: "Unknown member 'id' of 'com.mycompany.mailscomunes.R'. I haven't seen this error outside of AIDE.
This is the Java code:
package com.mycompany.mailscomunes;
import android.app.*;
import android.os.*;
import android.content.Intent;
import android.provider.ContactsContract;
public class MainActivity extends Activity
{
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
findViewById(R.id.one);
}
}
And this is the relevant XML:
<TextView
android:text="#string/hello_world"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/one"/>

Remove these lines:
import android.app.*;
import android.os.*;
You're literally importing the entire Android framework, which includes layout files, which has ID's in them.
And you're not including your own ID file (called "R.java").
So remove those two lines, and include this one:
import com.mycompany.mailscomunes.R;

The root of an activity xml should be of Layout type.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<TextView
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:text="Text"/>
</LinearLayout>

Goto your project and delete the build folder and do a rebuild. I had the same problem and is fixed

Error in findViewById in Android

I am getting error in speed = (TextView) findViewById(R.id.speed); saying "speed cannot be resolved or it is not a field".
My layout is:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".SpeedometerActivity" >
<Button
android:id="#+id/download"
android:layout_width="150dp"
android:layout_height="70dp"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_marginBottom="13dp"
android:layout_marginLeft="300dp"
android:text="Begin Test" />
<TextView
android:id="#+id/speed"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="#+id/meter"
android:layout_marginLeft="191dp"
android:layout_marginTop="55dp"
android:layout_toRightOf="#+id/meter"
android:text="TextView"
android:textSize="20dp"
android:textColor="#000000"/>
</RelativeLayout>
My MainActivity:
public class MainActivity extends Activity {
TextView speed;
Button download;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.speedometer);
download = (Button)findViewById(R.id.download);
}
#Override
protected void onResume() {
super.onResume();
h = new Handler();
new speedTask().execute();
speed = (TextView) findViewById(R.id.speed);
}
}
Please anybody help me to solve this problem.

"speed cannot be resolved or it is not a field"
Check if any errors in your resource files. Follow the suggestion by blackbelt. If you have errors in resource files your R.java will not be generated. Fix it. also check if you have import android.R; if so remove it.
Further you have
<TextView
android:id="#+id/speed"
Its a textview
Casting it to button
speed = (Button)findViewById(R.id.speed);
Should be
TextView speed =(TextView) findViewById(R.id.speed);

You should check if the R class you imported is the one of your project and not the android's one. Also you are casting to the wrong object, as correctly stated from #Raghunandan

Here you are type cast TextView to Button. So please change your code as below.
TextView speed = (Button)findViewById(R.id.speed);
Note : Here you are not able to import your project R file, first please check your xml file and try to resolve xml error first.
Please remove import android.R; from your activity if you have import it.
Go to your MainActivity.Java file and Press CTRL+SHIFT+O. It will automatically import all necessary packages.

It has created a duplicate so give as follows
Button speed1;
speed1=(Button)findViewById(R.id.speed);
It will work!

fiewViewById not finding my button (Eclipse)

I downloaded latest ADT from the main website and it came with Eclipse. So, I set everything up fine > Start new Android project. Set my settings, and the Activity to "Blank Activity", click finish.
Now, I go to the visual editor and add a button and some text. The problem is, is that "findViewById" is not detecting the button for some reason. Yes, I "Cleaned" the project and all that..
Here's the xml portion:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:layout_below="#+id/button1"
android:layout_marginTop="37dp"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="#+id/editText1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:ems="10" >
<requestFocus />
</EditText>
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:layout_below="#+id/editText1"
android:layout_marginTop="52dp"
android:text="#string/button" />
</RelativeLayout>
Here's my source code:
package com.example.tcp;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.Button;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button ibtn = (Button) findViewById(R.id.button1); // Error
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}

Did you actually save the activity_main.xml? View ID's are not accessible to the rest of the project until you save the layout you're working on.
I copied and pasted your code straight into a blank project and it worked fine after saving.

Its just the basic error so clean your project and build again if its not work then restart eclipse and start once again it will display your button.In the same way you followed
don't even import R.java it will show you error..
so clean and build your project

In your TextView you have
android:layout_below="#+id/button1"
Delete the plus so you have
android:layout_below="#id/button1"
Also it's better when you move the code of the textview below the code of the button. The Relative layout will position it where it's supposed to be anyway. But this way you don't link to an id that doesn't exist yet.
You declare a id with the + in the id. So in your case you declare it twice.
(Also for furure reference when you post something on StackOverflow with an error. Please mention the error in all cases. It makes finding the error and helping you a lot easier.)

I looked at the R file and it was empty before I "ran" the project. After clicking "run" it added the id fields in the file. Seems to be working fine now. I guess it was actually a problem with the activity_main.xml not saving. Thanks again

Beginner Android why is "id" is "Unknown member" with R.id?

I'm sure this is something dead simple as it's my first android app with code (the hello world example I did was just assigning a value to a string in XML). My problem is when trying to get the reference for my button in my variable then the id as in R.id is not defined?
The compiler error is in a comment in the code below where it occurs:
package com.geeksonhugs.simplecalc;
import android.app.*;
import android.os.*;
import android.view.*;
import android.widget.*;
public class MainActivity extends Activity
{
private Button AddButton;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
AddButton = (Button)findViewById(R.id.btnAdd);
//"Unknown member 'id' of 'com.geeksonhugs.simplecalc.R'"
//AddButton.setOnClickListener(this);
}
}
XML layout file:
<?xml version='1.0' encoding='utf-8' ?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/LayoutRoot"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:orientation="vertical">
<TextView
android:id="#+id/txtFirstNum"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:text="#string/strFirstNum" />
<EditText
android:id="#+id/edtFirstNum"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:text="" />
<TextView
android:id="#+id/txtSecondNum"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:text="#string/strSecondNum" />
<EditText
android:id="#+id/edtSecondNum"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:text="" />
<Button
android:id="#+id/btnAdd"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:text="#string/strAdd"
android:gravity="center" />
<TextView
android:id="#+id/txtResult"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:text="" />
</LinearLayout>

I resolved the issue by deleting the bin folder and recompiling using the AIDE App.

The R class is code-generated for you by the Android build tools when you build your project. This means there are four possibilities:
You have not tried building the project yet, in which case, try that.
Eclipse doesn't think it needs to build the project for some reason -- try Project > Clean from the Eclipse menu (only relevant if you are using Eclipse, of course).
There is some bug in your manifest or one of your resources that is preventing R from being built. There should be Eclipse error indicators for this.
You do not have an android:id attribute in your layout, and therefore there is no R.id available.

Please make sure the xml file you pasted is called main.xml and under layout folder.
And try to generate the R file again.
That may help.

For those using AIDE having issues referencing Id, try deleting the "gen folder" located in the bin folder and recompile. The problem is the R.java class did not create a constructor called Id. So deleting the gen folder containing the R.java class and recompiling solves this issue.

You must add id to a component in the XML file. Like this:
android:id="#+id/buton1"
Now can you click mainActivity.java and write code "R.id." you a see hint to write "buton1" and no error of "id"

Android problem

Hi iam working on android getting the following problem for my login but i didn't got my mistake... The error notice is the application has been terminated unexpectedly
my code is
package layout.program;
import android.app.Activity;
import android.os.Bundle;
public class Tablelayout extends Activity{
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.tablelayout);
}
}
tablelayout.xml
<?xml version="1.0" encoding="utf-8"?>
<TableLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TableRow android:id="#+id/tableRow1" android:layout_width="wrap_content" android:layout_height="wrap_content">
<TextView android:layout_height="wrap_content" android:text="TextView" android:id="#+id/textView1" android:textAppearance="?android:attr/textAppearanceMedium" android:layout_width="wrap_content"></TextView>
<EditText android:id="#+id/editText1" android:layout_height="wrap_content" android:layout_width="fill_parent">
<requestFocus></requestFocus>
</EditText>
</TableRow>
</TableLayout>

Try Cleaning your Project..
By Selecting the Project and then go to top project option and then select clean.
and then select OK..
Sometimes Changes are not made in R.java...Thats y this error comes

Your code is working fine at my end..please look in your code if there is anything which is causing the exception..Try to debug with debugger....

There's nothing wrong with your code or xml, so it has to be an error in your manifest.
As this application is just a stub, why not do this:
Create a new Android project, call it anything you like.
Call the activity 'TableLayoutActivity'
Put your tablelayout.xml into the layout folder.
Change the automatically generated code in TablelayoutActivity.java to set the content view from setContentView(R.layout.main) to setContentView(R.layout.tablelayout)
This should work, then have a look at the manifest in the new project, to see where you went wrong in your original project.

change the class name and try again,also check if the activity name mentioned in the android manifest is correct.