Develop Reference

Button wont start another activitie

my button with the id radio, to start second activity, isnt working and my app keeps crashing. The second button however starts another activity wich is empty for the moment. can somebody please tell me what did i miss, so my app stops crashing when i press the button.
my first activity xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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="com.example.mitja.radiohead.PrvaStran">
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayou 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="com.example.mitja.radiohead.PrvaStran">
<LinearLayout
android:layout_width="368dp"
android:layout_height="0dp"
android:orientation="vertical"
android:paddingLeft="16dp"
android:paddingRight="16dp"
tools:layout_editor_absoluteX="0dp"
tools:layout_editor_absoluteY="49dp"
android:weightSum="1">
<ImageView
android:id="#+id/slika"
android:layout_width="match_parent"
android:layout_height="218dp"
android:layout_weight="0.16"
android:src="#drawable/radio"
android:layout_marginLeft="1dp"
android:layout_marginRight="2dp"
tools:layout_editor_absoluteX="8dp"
tools:layout_editor_absoluteY="16dp" />
<Button
android:id="#+id/radio"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginRight="10dp"
android:layout_weight="0.50"
android:text="radio"
tools:layout_editor_absoluteX="8dp"
tools:layout_editor_absoluteY="323dp" />
<Button
android:id="#+id/predvajalnik"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginRight="10dp"
android:text="predvajalnik"
tools:layout_editor_absoluteX="8dp"
tools:layout_editor_absoluteY="371dp" />
</LinearLayout>
java code of the first activity
public class PrvaStran extends AppCompatActivity {
private static Button btn1;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_prva_stran);
onClickButton();
onClickButton2();
}
public void onClickButton()
{
btn1 = (Button) findViewById(R.id.radio);
btn1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent openMainAct = new Intent(PrvaStran.this, Radio.class);
startActivity(openMainAct);
}
});
}
public void onClickButton2()
{
btn1 = (Button) findViewById(R.id.predvajalnik);
btn1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent("com.example.mitja.radiohead.Predvajalnik");
startActivity(intent);
}
});
}
}
and the android manifestxml code.
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.mitja.radiohead">
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity android:name=".PrvaStran">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".Radio"
android:label="#string/app_name">
<intent-filter>
<action android:name="com.example.mitja.radiohead.Radio" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
<activity android:name=".Predvajalnik">
<intent-filter>
<action android:name="com.example.mitja.radiohead.Predvajalnik" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
</application>
what am i missing here? the second activity is made from a tutorial i saw on youtube to create a listview with images and texts. I got the code from this site now im trying to use it in this app for practice. i havent had any experiance with android studio before so im asking for a little guide.

In your code you are referencing same button to two different ids
private Button btn1;
btn1 = (Button) findViewById(R.id.radio);
btn1 = (Button) findViewById(R.id.predvajalnik);
That is why app is getting crashed.
declare two different buttons and then refer them to respected ids.
private Button btn1;
private Button btn2;
btn1 = (Button) findViewById(R.id.radio);
btn2 = (Button) findViewById(R.id.predvajalnik);

You don't need to write the buttons as fields, but you do need to actually set both buttons listeners
findViewById(R.id.radio).setOnClickListener(
...
);
findViewById(R.id.predvajalnik).setOnClickListener(
...
);

Starting activity from fragment button click (intent) throws blank screen

I'm trying to start an activity from a button which is placed in a fragment, but when I run the app (in emulator and in a real device) and I press that button, the activity doesn't start and a blank screen whithout navigation bar appears. I've read a lot about this, and the most common error people had is that they didn't declare the Activity or they weren't inflating the correct layout. Any idea would be appreciated, because I don't now what to do right now.
Here is the code of the manifest:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.isa.example" >
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="#string/app_name"
android:screenOrientation="portrait"
android:theme="#style/Theme.CustomMaterial" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".NewActivity"
android:label="#string/app_name"
android:screenOrientation="portrait"
android:theme="#style/Theme.CustomMaterial" >
<intent-filter>
<action android:name="com.isa.example.NewActivity" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
Here is the code for the fragment layout:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/container"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
tools:context=".MainActivity">
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Start new activity"/>
</RelativeLayout>
Code for the fragment:
public class Fragment1 extends Fragment {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_fragment1, container, false);
Button button = (Button) view.findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent i = new Intent(getActivity(), NewActivity.class);
startActivity(i);
}
});
return view;
}
}
Code for the new activity layout:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="This is new activity"
android:id="#+id/textView"
android:layout_gravity="center_horizontal" />
</LinearLayout>
And code for the new activity:
public class NewActivity extends Activity{
#Override
public void onCreate(Bundle savedInstanceState, PersistableBundle persistentState) {
super.onCreate(savedInstanceState, persistentState);
setContentView(R.layout.newactivity_layout);
}
}

What is your minimum sdk version? Your version of onCreate is introduced in 21: stackoverflow.com/a/29871359/1541763 Remove the PersistableBundle persistentState from your parameters

FragmentActivity Buttons to switch between Fragments

All I want to do is a simple Button page switcher between the MainActivity and ArticleGroups pages. I will be implementing a paging class afterwards but I want to get the buttons working first.
Once I run the Application the app will crash and force close so I am certainly doing something wrong.
MainActivity.java
public class MainActivity extends FragmentActivity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button b = (Button)findViewById(R.id.articlebtn);
b.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick (View v) {
Intent i = new Intent(MainActivity.this, ArticleGroup.class);
startActivity(i);
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
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:layout_width="match_parent"
android:layout_height="match_parent" tools:context=".MainActivity">
<fragment
android:id="#+id/activitymain_fragment"
android:name="com.dharris.mindfulemployer_v4.MainActivity"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<Button
android:id="#+id/articlebtn"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:background="#color/aqua"
android:onClick="onClick" />
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/articlebtn"
android:layout_alignBottom="#+id/articlebtn"
android:layout_toRightOf="#+id/articlebtn"
android:text="#string/hello_world" />
</RelativeLayout>
ArticleGroup.java
public class ArticleGroup extends FragmentActivity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.articlegroup);
Button b = (Button) findViewById(R.id.articlebtn);
b.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent i = new Intent(ArticleGroup.this, MainActivity.class);
startActivity(i);
}
});
}
}
articlegroup.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<fragment
android:id="#+id/articlegroupfragment"
android:name="com.dharris.mindfulemployer_v4.ArticleGroup"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<Button
android:id="#+id/articlebtn"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:background="#color/aqua"
android:onClick="onClick" />
</RelativeLayout>
Manifest File
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.dharris.mindfulemployer_v4"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="11"
android:targetSdkVersion="19" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<!-- Activity Default -->
<activity
android:name="com.dharris.mindfulemployer_v4.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<!-- Activity ArticleGroup -->
<activity
android:name=".ArticleGroup"
android:label="#string/app_name"
></activity>
</application>
</manifest>
If anyone can make sense as to why this is not working then I will be very appreciative.

You have
android:onClick="onClick" />
You need to have a method by name onClick in Activity which takes view as a param
You can remove this
Button b = (Button)findViewById(R.id.articlebtn);
b.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick (View v) {
Intent i = new Intent(MainActivity.this, ArticleGroup.class);
startActivity(i);
}
});
And have
public void onClick(View V)
{
// do something on button click
}

Delete this line from activity_main.xml and articlegroup.xml
android:onClick="onClick"

My app stops working

I am writing a basic application which contains two activities. Both contain a TextView showing the title and the first one contains an EditText in which the user types a message and clicks on a button on its side, the second activity is launched which shows the message the user types.
It has the following problem:
1.When I click on the button, the app stops saying "Unfortunately Write n Display and stopped.", rather than launching the second activity at all.
The Logcat can be found here: enter link description here since adding it to the question exceeded the limit.
CODE OF FIRST ACTIVITY: -
package com.practice.myfirstapp1;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
//import android.view.Menu;
public class MainActivity extends Activity {
public static final String key_name="com.practice.firstApp.key";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void sendMessage(View view){
Intent intent= new Intent(this, SecondActivity.class);
EditText editText=(EditText) findViewById(R.id.EditText1_MainActivity);
String key_value= editText.getText().toString();
intent.putExtra(key_name, key_value);
startActivity(intent);
}
}
LAYOUT OF FIRST ACTIVITY: -
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >
<TextView
android:id="#+id/TextView1_MainActivity"
android:layout_alignParentTop="true"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:text="#string/title_MainActivity"
android:textStyle="bold"/>
<EditText
android:id="#+id/EditText1_MainActivity"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/TextView1_MainActivity"
android:hint="#string/EditText_MainActivity"
android:textStyle="italic" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#id/TextView1_MainActivity"
android:layout_toRightOf="#id/EditText1_MainActivity"
android:text="#string/Button_MainActivity"
android:onClick="sendMessage"/>
</RelativeLayout>
CODE OF SECOND ACTIVITY: -
package com.practice.myfirstapp1;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;
class SecondActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
Intent intent= getIntent();
String intent_value= intent.getStringExtra(MainActivity.key_name);
TextView textView= new TextView(this);
textView= (TextView) findViewById(R.id.TextView2_SecondActivity);
textView.setText(intent_value);
}
}
LAYOUT OF SECOND ACTIVITY: -
<?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:orientation="horizontal"
tools:context=".SecondActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:text="#string/title_SecondActivity"
android:textStyle="bold"/>
<TextView
android:id="#+id/TextView2_SecondActivity"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</RelativeLayout>
STRINGS RESOURCE FILE:-
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="app_name">Write n Display</string>
<string name="action_settings">Settings</string>
<string name="title_MainActivity">WRITE</string>
<string name="EditText_MainActivity">Your Message here</string>
<string name="Button_MainActivity">Send</string>
<string name="title_SecondActivity">DISPLAY</string>
</resources>
ANDROID MANIFEST FILE: -
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.practice.myfirstapp1"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="18" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme"
android:debuggable="true" >
<activity
android:name="com.practice.myfirstapp1.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name="com.practive.myfirstapp1.SecondActivity"
android:label="#string/app_name">
</activity>
</application>
</manifest>

To solve your first issue: put below code to your textview of both xml files.
Reason: You had not put the android:layout_centerHorizontal="true" in your TextView
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:text="#string/title_MainActivity"
To solve your second issue:Change LAYOUT OF FIRST ACTIVITY:
Reason: android:layout_width is "0dp". it should be wrap_content or fill_parent or match_parent
<EditText
android:id="#+id/EditText1_MainActivity"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_below="#+id/TextView1_MainActivity"
android:hint="#string/EditText_MainActivity"
android:textStyle="italic" />
To:
<EditText
android:id="#+id/EditText1_MainActivity"
android:layout_width="wrap_content" //you can put, fill_parent or match_parent
android:layout_height="wrap_content"
android:layout_below="#+id/TextView1_MainActivity"
android:hint="#string/EditText_MainActivity"
android:textStyle="italic" />
To solve your third issue: change your CODE OF FIRST ACTIVITY: -
Reason: You had put editText=(EditText) findViewById(R.id.EditText1_MainActivity); in sendMessage(View view). send message contains a View so whenever you initiate any component in this method, it will search that component on this particular view which is incorrect. you can initiate your components in any method which does not contain any view parameter.if you want to initiate any component in particular view then you have to initiate it like editText=(EditText)view.findViewById(R.id.EditText1_MainActivity);. But in your case edittext is in main view so you need to remove it from sendMessage(View view).
public class MainActivity extends Activity {
public static final String key_name="com.practice.firstApp.key";
EditText editText;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
editText=(EditText) findViewById(R.id.EditText1_MainActivity);
}
public void sendMessage(View view){
Intent intent= new Intent(this, SecondActivity.class);
String key_value= editText.getText().toString();
intent.putExtra(key_name, key_value);
startActivity(intent);
}
}
Change your second Activity
Reason: TextView textView= new TextView(this); is not correct way to initialize any component of your xml view.
TextView textView= new TextView(this);
textView= (TextView) findViewById(R.id.TextView2_SecondActivity);
textView.setText(intent_value);
To:
TextView textView;
textView= (TextView) findViewById(R.id.TextView2_SecondActivity);
textView.setText(intent_value);

you can solve your problem like this
1.replace
android:gravity="center_horizontal" by android:layout_gravity="center_horizontal".
2.Give layout_width as wrap_content for edittext of first activity xml
3.Make your sendMessage method public not private
To get the logcat In Eclipse, Goto Window-> Show View -> Other -> Android-> Logcat.
OR
Write LogCat in Quick Access edit box in your eclipse window (top right corner, just before Open Prospective button). And just select LogCat it will open-up the LogCat window in your current prospec

change private void sendMessage(View view) to public void sendMessage(View view) (private to public)
LAYOUT OF FIRST ACTIVITY:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center_vertical" >
<TextView
android:id="#+id/TextView1_MainActivity"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#+string/title_MainActivity"
android:textStyle="bold"/>
<EditText
android:id="#+id/EditText1_MainActivity"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:hint="#string/EditText_MainActivity"
android:textStyle="italic" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/Button_MainActivity"
android:onClick="sendMessage"/>
LAYOUT OF SECOND ACTIVITY: -
<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:orientation="horizontal"
android:gravity="center_vertical"
tools:context=".SecondActivity">
<TextView
android:layout_alignParentTop="true"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#+string/title_SecondActivity"
android:textStyle="bold"/>
<TextView
android:id="#+id/TextView2_SecondActivity"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />

Logcat shows the following:
Caused by: android.content.ActivityNotFoundException: Unable to find
explicit activity class
{com.practice.myfirstapp1/com.practice.myfirstapp1.SecondActivity};
have you declared this activity in your AndroidManifest.xml?
You did define SecondActivity in manifest, but the package name is wrong ( android:name="com.practive.myfirstapp1.SecondActivity" should be ndroid:name="com.practice.myfirstapp1.SecondActivity"
).
<activity
android:name="com.practice.myfirstapp1.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name="com.practive.myfirstapp1.SecondActivity"
android:label="#string/app_name">
</activity>
It should be
<activity
android:name="com.practice.myfirstapp1.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name="com.practice.myfirstapp1.SecondActivity"
android:label="#string/app_name">
</activity>

Android fragments setRetainInstance(true) not works (Android support library)

I have a problem with saving fragment state. I try to use setRetainInstance, but cant make it work((( I change a state to 2 using button1, but after changing screen orientation i see 1 when pressing on button2. Where is my mistake?
public class TestFragment extends Fragment {
#Override
public void onCreate(Bundle savedInstanceState) {
setRetainInstance(true);
super.onCreate(savedInstanceState);
}
private String state = "1";
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_layout, container, false);
//button for changing state
((Button)view.findViewById(R.id.button1)).setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
state = "2";
}
});
//button for showing state
((Button)view.findViewById(R.id.button2)).setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
Toast.makeText(getActivity(), state, Toast.LENGTH_SHORT).show();
}
});
return view;
}
}
EDIT
Activity:
public class MainActivity extends FragmentActivity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
}
Activity layout:
<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" >
<fragment
android:name="ru.ee.TestFragment"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
</RelativeLayout>
Fragment layout:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Change to 2" />
<Button
android:id="#+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Show" />
</LinearLayout>
Manifest XML:
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="ru.ee.testfrag"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="15" />
<application
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="ru.ee.MainActivity"
android:label="#string/title_activity_main" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>

Your fragment will only get re-used if you give the fragment an Id in the layout, change
<fragment
android:name="ru.ee.TestFragment"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
to be
<fragment
android:id="#+id/a_fragment"
android:name="ru.ee.TestFragment"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>

There isn't anything wrong with the code you posted. If you have the fragment implemented correctly, it should be giving you a state of 2. Maybe you could post your activity and xml files. There error must be somewhere else.