Develop Reference

Why can't android:onClick recognize the specfied function?

Java Code:-
package com.example.plannerv1;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import org.w3c.dom.Text;
import java.util.ArrayList;
public class DisplayNotes extends AppCompatActivity {
handledatabaseonhomescreen handle_db_notes = new handledatabaseonhomescreen();
private int key;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_display_notes);
Intent incomingintent = getIntent();
key = incomingintent.getIntExtra("key",-1);
displaydate(key);genanddisplay();
}
protected void addanote(View v)
{
Intent goback = new Intent();
goback.putExtra("returnkey",-100);
goback.putExtra("datewas",key);
setResult(RESULT_OK,goback);
finish();
}
protected void onActivityResult(int requestCode,int resultCode,Intent intent)
{
genanddisplay();
}
}
XML code:-
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:gravity="top|center"
android:layout_height="match_parent"
tools:context=".DisplayNotes"
android:orientation="vertical">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="20sp"
android:paddingBottom="20sp"
android:textStyle="bold"
android:gravity="center"
android:textSize="20dp"
android:id="#+id/dmy"/>
<ListView
android:layout_width="match_parent"
android:layout_height="0px"
android:paddingTop="20sp"
android:paddingBottom="20sp"
android:paddingLeft="5sp"
android:paddingRight="6sp"
android:layout_weight="10"
android:id="#+id/displaynote">
</ListView>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="20sp"
android:text="Add Note"
android:onClick="addanote"/>
</LinearLayout>
Error:-
java.lang.IllegalStateException: Could not find method addanote(View) in a parent or ancestor Context for android:onClick attribute defined on view class androidx.appcompat.widget.AppCompatButton
at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.resolveMethod(AppCompatViewInflater.java:424)
at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:381)
at android.view.View.performClick(View.java:5619)
at android.view.View$PerformClick.run(View.java:22298)
at android.os.Handler.handleCallback(Handler.java:754)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:165)
at android.app.ActivityThread.main(ActivityThread.java:6375)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:912)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:802)
I can't figure out why the onClick tag doesn't attach the button to the specified function.
I tried to Google the problem but nothing could help me. I tried changing the name and checking if the files are linked but nothing helps.
And I'm sorry about the ugly formatting on the error but stackoverflow wouldn't let me post.
AndroidStudio gives this warning:-
Method 'addanote' in 'DisplayNotes' has incorrect signature less... (Ctrl+F1)
Inspection info: Checks if the method specified in onClick XML attribute is declared in related activity

You addanote() function must be public, not protected:
public void addanote(View v)
Docs: https://developer.android.com/guide/topics/ui/controls/button#java

As #Marcin mentioned, you should use public instead of protected. Also, you can use a different but better approach, add a listener on the Button:
Add an id attribute to the Button, then define the listener in the onCreate() method.
XML:
<Button
android:id="addNote"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="20sp"
android:text="Add Note"/>
Then Java:
#Override
protected void onCreate(Bundle savedInstanceState) {
...
Button addNote = findViewById(R.id.addNote);
addNote.setOnClickListner(new View.OnClickListener() {
#Override
public void onClick() {
//Your code to be implemented when button is clicked.
}
});
...
}

The 'MainActivity' activity had a function with the same name and parameters and changing 'addanote' to something else somehow solved the problem. I had no idea it would interfere with the 'DisplayNotes' Activity. Needs to be public though.

You need to make the method public as mentioned here
https://developer.android.com/guide/topics/ui/controls/button#java
The method you declare in the android:onClick attribute must have a signature exactly as shown above. Specifically, the method must:
Be public
Return void
Define a View as its only parameter (this will be the View that was clicked)
the code is working fine after making it public
enter image description here

Android Studio - Button Click Crash (Simple)

I'm brand new to Android Studio and for whatever reason am experiencing really weird errors if I could please get some help.
I have very basic code that is supposed to, on button click change the text of my button from "button" to "clicked!". However everytime I press the button, the app crashes and I get "Appname has stopped" on the emulator.
What is incredibly weird is that in my activity_main.xml Design view, the onClick dropdown shows two functions of the same name (https://puu.sh/t2h5I/42ad4379d6.png)
H owever the code only works when the bottom one is selected. AND each time I run the app, it deselects the bottom one and reselects the top, only to stop working.
Here is my MainActivity:
package com.example.john.ameladay;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
public Button melButtonCode;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void buttonPress(View v){
melButtonCode = (Button) v;
((Button) v).setText("Has been clicked!");
}
}
Here is my activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/activity_main"
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="com.example.john.ameladay.MainActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/mainText"
android:id="#+id/textView" />
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:src="#drawable/mela"
android:id="#+id/melPhoto" />
<Button
android:text="Button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_toRightOf="#+id/textView"
android:layout_toEndOf="#+id/textView"
android:layout_marginLeft="32dp"
android:layout_marginStart="32dp"
android:layout_marginBottom="43dp"
android:id="#+id/button"
android:onClick="buttonPress (MainActivity)" />
Any help would be greatly appreciated!!

Simple. You should write:
android:onClick="buttonPress"
Why happened
If you wrote buttonPress (MainActivity), Android tries to find buttonPress (MainActivity) method (not MainActivity.buttonPress()), but MainActivity doesn't have buttonPress (MainActivity) method. So the error happened.

Simply replace this Tag in button
Remove this
android:onClick="buttonPress (MainActivity)"
And Paste This
android:onClick="buttonPress"

A better way to do it is, get a reference to the button in your Java code using findViewById() method and set an OnClickListener to the button.
For your current problem, use
android:onClick="buttonPress"
instead of
android:onClick="buttonPress (MainActivity)"

According to me this is the better way to set click on button
public class MainActivity extends AppCompatActivity {
public Button melButtonCode;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
melButtonCode = (Button).findViewById(R.id.button);//find button by Id
melButtonCode.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
melButtonCode.setText("Has been clicked!");
}
});
}
}
For your problem
replace it
android:onClick="buttonPress (MainActivity)"
With
android:onClick="buttonPress"

Make the method public - protected works when you are in instantrun mode, but not when not. No idea why!

App chrashes while changing view

I want to create a very simple app. The app should consists of 2 views. In both views are one button. By clicking the button the view should change.
Here is my folder structure
I have two activitys and two activity_layouts. As you can see OverviewActivity isn't inside the activity folder. When I place it into the folder I get this structur:
Why is the activity folder away? Can you give me a little explanation?
Ok, but in this question I use the first folder structur.
activity_login.xml
<?xml version="1.0" encoding="utf-8"?>
<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="company.useradministration.activity.LoginActivity">
<Button
android:layout_width="match_parent"
android:layout_height="match_parent"
android:onClick="btnOverview"
android:text="go to overview"/>
</RelativeLayout>
activity_overview.xml
<?xml version="1.0" encoding="utf-8"?>
<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=".activity.OverviewActivity">
<Button
android:layout_width="match_parent"
android:layout_height="match_parent"
android:onClick="btnLogin"
android:text="go to login"/>
</RelativeLayout>
LoginActivity
package company.useradministration.activity;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import company.useradministration.R;
public class LoginActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
}
public void btnOverview(View view){
setContentView(R.layout.activity_overview);
}
}
OverviewActivity
package company.useradministration.activity;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import company.useradministration.R;
public class OverviewActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_overview);
}
public void btnLogin(View view){
setContentView(R.layout.activity_login);
}
}
Okay. When I start the app, I see a button with the text "go to view". After pressing this button, the view changed. Now I see a button with the text "go to overview". When I press this button, the app crashes with the error:
java.lang.IllegalStateException: Could not find method btnOverview(View) in a parent or ancestor Context for android:onClick attribute defined on view class android.support.v7.widget.AppCompatButton
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.resolveMethod(AppCompatViewInflater.java:307)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:266)
at android.view.View.performClick(View.java:4438)
at android.view.View$PerformClick.run(View.java:18439)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5085)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:611)
at dalvik.system.NativeStart.main(Native Method)

UPDATE:
Here is the explained answer:
You have a activity_overview.xml with it's class OverviewActivity.
In your activity_overview.xml you set the android:onClick="btnLogin" to the button and you have:
public void btnLogin(View view){
setContentView(R.layout.activity_login);
}
in your OverviewActivity so when user clicks this button it changes the contentview successfully.
The question here is:
Why does the app crashes when you click on the button in activity_login.xml to change the contentview back to activity_overview.xml?
Simple. Because you have set the onclick method in your LoginActivity but you aren't switching to that activity but just changing the layout. So when the button to go back to overview content is clicked the app searches for the function in you OverviewActivity because the activity didn't swithed to LoginActivity. It has just changed the content and there is no function called btnOverview in your OverviewActivity. So here you have 2 solutions:
1- Create two RelativeLayouts in just one xml file and than setVisibility of each layouts on button click.
So for that you have to:
Create only one activity instead of two different and in it's xml file use this code:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/overview"
android:visibility="gone">
<Button
android:layout_width="wrap_content"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true"
android:text="go to login"
android:id="#+id/go_to_login"
android:layout_height="wrap_content" />
//Do your stuff here for overview content
</RelativeLayout>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/login">
<Button
android:layout_width="wrap_content"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true"
android:text="go to overview"
android:id="#+id/go_to_overview"
android:layout_height="wrap_content" />
//Do your stuff here for login content
</RelativeLayout>
</RelativeLayout>
This code has 2 RelativeLayouts. The first one with id:overview is of the overview content and it's visibility is gone and the second RelativeLayout with id:login has the visibility visible by default (Change the two layouts visibility as desired).
Than in your MainActivty.java (call it as you wish) you can change the visibility of these views like this:
public class MainActivity extends AppCompatActivity {
Button goToOverview, goToLogin;
RelativeLayout overview, login;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//Remember to change the content to match your xml file name
setContentView(R.layout.activity_main);
//Buttons
goToOverview = (Button) findViewById(R.id.go_to_overview);
goToLogin = (Button) findViewById(R.id.go_to_login);
//Layouts
overview = (RelativeLayout) findViewById(R.id.overview);
login = (RelativeLayout) findViewById(R.id.login);
goToOverview.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
login.setVisibility(View.GONE);
overview.setVisibility(View.VISIBLE);
}
});
goToLogin.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
overview.setVisibility(View.GONE);
login.setVisibility(View.VISIBLE);
}
});
}
In this way you can switch to two different layout without any problem.
Edit: You can achieve this also with this solution but the difference between the first solution and this solution is just that you will have 2 xml files instead of one.
2nd- You will have one java class file (in this example I will take OverviewActivityas example) and 2 different layout files (Which you already have: activity_login.xml and activity_overview.xml).
So in your activity_overview.xml change this line: tools:context=".activity.OverviewActivity" to tools:context=".OverviewActivity" as you said that you are using the first folder structure where the OverviewActivity file is out of the activity folder.
Than in your OverviewActivity make the following changes:
public class OverviewActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_overview);
}
public void btnLogin(View view){
setContentView(R.layout.activity_login);
}
public void btnOverview(View view){
setContentView(R.layout.activity_overview);
}
}
That's it. Please comment if you are having any problem with the code. I will be glad to help your further more.
Hope this can solve your issue.
Regards

I think this is your problem:
public void btnOverview(View view){
setContentView(R.layout.activity_overview);
}
This changes the layout for the current activity LoginActivity to activity_overview which contains the button thats looking for the btnLogin method
You are successfully changing the layout, but your staying in the same activity, so the new layout is looking for a method that exists in the other activity
Instead change the above code to this:
public void btnOverview(View view){
Intent intent = new Intent(this, OverviewActivity.class);
startActivity(intent);
}
And in OverviewActivity
public void btnLogin(View view){
Intent intent = new Intent(this, LoginActivity.class);
startActivity(intent);
}

I think you can use this as a help. I'm newbie myself to android java programming, but I believe you have to create intent to move to another activity. Additionally be sure to add your Activity to AndroidManifest.xml. That's all I think. If I'm wrong I'll be happy if someone more experienced will correct me :)

Android - error when using ViewFlipper

eveything looks to be fine, but I still get error when I try to change the view by pressing the button.
Here is code:
package com.example.testy;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.ViewFlipper;
public class MainActivity extends Activity {
ViewFlipper flipper;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
flipper = (ViewFlipper) findViewById(R.id.viewFlipper1);
setContentView(R.layout.activity_main);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
public void clcik(View v) {
flipper.showNext();
}
}
And here is my XML:
<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:gravity="top" >
<ViewFlipper
android:id="#+id/viewFlipper1"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="click"
android:text="Button!!" />
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TextView!!" />
</ViewFlipper>
</RelativeLayout>
Anyone knows what can be wrong in this code?
Thank you for answers!

Perhaps you should fix the name of your method to click ?
public void **clcik**(View v) {
flipper.showNext();
}
Due the wrong spell (clcik) in our activity code, you may be getting a Exception because Android can't find the click method.
And thanks to #yugidroid's answer I spot one more error on your code:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
flipper = (ViewFlipper) findViewById(R.id.viewFlipper1);
setContentView(R.layout.activity_main);
}
You call findViewById before even you have any Views (a call to setContentView) . You will get a NullPointException because of that.
I would recommend you to make a call to super.onCreate the very first line of your onCreate() method. That is what Google does.
Regarding setting the click listener on layout or creating a listener and setting on the code. Well, there is not much difference, although the latter is certainly faster as the first uses reflection, what has a higher cost than just calling a method.

First of all, make sure you call setContentView(R.layout.activity_main); after the super, its a good practice.
Your problem is that you set android:onClick="click" but you are refering the wrong method in Java (clcik doesn't exists).
I advice you to declare and set listeners in the activity, not in the xml.

Null pointer exception in TextView

This is my layout
<?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"
android:orientation="vertical" >
<TextView
android:id = "#+id/postQues"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Post A Question" />
<TextView
android:id="#+id/postAnswer"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:text="Post Your Answer" />
<Button
android:id="#+id/submit"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:clickable="true"
android:text="Submit" />
</RelativeLayout>
This is my activity:
package com.qstack.quizbox;
import roboguice.activity.RoboActivity;
import roboguice.inject.ContentView;
import roboguice.inject.InjectView;
import android.content.DialogInterface;
import android.view.View.OnClickListener;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import com.app.main.R;
#ContentView(R.layout.q_box)
public class QuizBox extends RoboActivity {
#InjectView(R.id.postQues) TextView postQues;
#InjectView(R.id.postAnswer) EditText postAnswer;
//#InjectView(R.id.submit) Button submitA;
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
PostQuestion postQuestion = new PostQuestion();
postQues.setText(postQuestion.postQuestion());
submitA.setOnClickListener(submitAnswerListener);
}
private OnClickListener submitAnswerListener = new OnClickListener() {
//onClick view
public void onClick(View v) {
String answer;
answer = postA.getText().toString();
CheckAnswer checkAnswer = new CheckAnswer();
if (answer == checkAnswer.checkAnswer()) {
postA.setText("Correct");
}
}
};
}
I am getting a null pointer exception at line number 48, caused because postQues = null. When I remove postAnswer from the code, there is no null pointer exception. I've cleaned my project and all that. Any help

I can't comment yet on your answers, but people miss the point: he, like me, is using RoboGuice to inject views and stuff.
The sole purpouse of this framework is to avoid the boiler-plate part on onCreate() where you won't need to use setContentView and findViewById() anymore !
As to why he gets a NullePointerException, I don't know. I happen to have the same issue on one of my activies although it works just fine on all the other...
[EDIT]
I found the solution : I mixed up the type of two views.
If you put setContentView() where it is supposed to be, you will get the error.
The application wil say it cannot assign. Because the type doesn't match.
Therefore you get a nice
java.lang.RuntimeException: Unable to start activity ComponentInfo
But if you use RoboGuice framework, you get such error (well in my case I did not). However, all you views will all be null.
Hope it will help someone someday.

protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.yourxml); // you have missed this.....
PostQuestion postQuestion = new PostQuestion();
postQues.setText(postQuestion.postQuestion());
submitA.setOnClickListener(submitAnswerListener);
}

I had the same issue, and followed Mackovich's suggestions. He's right in pointing out that you don't need setContentView() with RoboGuice, as long as you annotate your activity with #ContentView.
In my case, the issue was caused by the fact that I had replaced an AutoCompleteTextView with an EditText, but forgot to make the same replacement in the activity with corresponding #InjectView. This was causing my NullPointerException.
Again, like Mackovich said, if I use setContentView() instead of #ContentView, the stacktrace gives me a more useful message:
Caused by: java.lang.IllegalArgumentException: Can't assign class android.support.v7.internal.widget.TintEditText value android.support.v7.internal.widget.TintEditText#426ce048 to class android.widget.AutoCompleteTextView field usernameTextView
I guess that's an argument against using Roboguice's #ContentView, at least until a fix is made in order to show the correct stacktrace.

You need to call setContentView(R.layout.the_xml) first (right after super.onCreate()). Otherwise RoboGuice doesn't know what to inject into your variables!

You forgot the following line in your code,
setContentView(R.layout.main);
which should be after this line of onCreate() method
super.onCreate(savedInstanceState);

you have missed that line
setContentView(R.layout.xml_filename);