Develop Reference

App is not opening in Android 5.1 and lower version devices

I created an app using android studio. Uploaded to play store. Its working fine in all devices except android version 5.1 and lower version devices. The app is not even opening in those devices.
I have tried my best to solve this problem but I failed.
.
So, please tell me guys how to solve it??
.
In stack trace it is showing :
.
Caused by : android.view.inflateException
.
At packageName.splash.oncreate (Splash.java:23)
.
Here Splash.java is my splash screen activity...
Here is my Splash.java code :
public class Splash extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_splash);
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
setupWindowAnimations();
TextView textView = findViewById(R.id.textviewmain);
TextView textView1 = findViewById(R.id.textviewmain2);
ImageView logo = findViewById(R.id.logo_s);
Animation animation1 = AnimationUtils.loadAnimation(getApplicationContext(),R.anim.fadein);
logo.startAnimation(animation1);
textView.startAnimation(animation1);
textView1.startAnimation(animation1);
Thread timer = new Thread(){
#Override
public void run(){
try {
sleep(3000);
Intent intent = new Intent(getApplicationContext(), MainActivity.class);
startActivity(intent);
finish();
super.run();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
timer.start();
}
private void setupWindowAnimations() {
Fade fade = new Fade();
fade.setDuration(3000);
getWindow().setExitTransition(fade);
}
}
and activity_splash.xml code is :
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
android:background="#092865"
tools:context=".Splash"
android:theme="#style/AppTheme.NoActionBar">
<ImageView
android:id="#+id/splashbg"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="-315dp"
android:src="#drawable/splashbg2"
/>
<RelativeLayout
android:id="#+id/slidesplash"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_marginBottom="100dp"
android:paddingBottom="5dp"
android:paddingTop="5dp"
android:background="#null"
android:gravity="center_horizontal">
<ImageView
android:id="#+id/logo_s"
android:layout_width="60dp"
android:layout_height="60dp"
android:layout_centerVertical="true"
android:contentDescription="#string/daily_highlights_dose"
android:src="#drawable/icon24"
android:transitionName="logo" />
<TextView
android:id="#+id/textviewmain"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="10dp"
android:layout_centerVertical="true"
android:layout_toEndOf="#id/logo_s"
android:text="#string/sports"
android:textColor="#ffffff"
android:textSize="25sp" />
<TextView
android:id="#+id/textviewmain2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="5dp"
android:layout_centerVertical="true"
android:layout_toEndOf="#+id/textviewmain"
android:text="Highlights"
android:textColor="#1FD883"
android:textSize="27sp" />
</RelativeLayout>
<!-- #f93959 -->
</RelativeLayout>

I think this problem is ocuuring just because of size of images,
You should check your image size which are put in splash Activity
or replace those images by others and then check it

Android AutoCompleteTextView return wrong string

I have a little problem in my android app. I want to put a word in an AutoCompleteTextView and then jump to a specific Activity(depend on the word that the user gave).
The problem is that, when i give a specific word, the program does not correspond with the correct answer as expected but returns a wrong toast message. However with the log that i put i see the correct answer. I think that the solution is silly but i stuck and need to solve this.
the code:
Activity.java
public class paralActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_paral);
final String [] temp = {"one","two","three"};
AutoCompleteTextView actv = (AutoCompleteTextView) findViewById(R.id.autoCompleteTextView);
actv.clearListSelection();
final RelativeLayout myRelative = (RelativeLayout) findViewById(R.id.find);
myRelative.setVisibility(View.INVISIBLE);
ImageView myImage = (ImageView) findViewById(R.id.aktoploika);
myImage.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent(paralActivity.this, topParalActivity.class);
startActivity(intent);
}
});
ImageView myOtherImage = (ImageView) findViewById(R.id.aeroporika);
myOtherImage.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
myRelative.setVisibility(View.VISIBLE);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(paralActivity.this, android.R.layout.select_dialog_item, temp);
//Getting the instance of AutoCompleteTextView
AutoCompleteTextView actv = (AutoCompleteTextView) findViewById(R.id.autoCompleteTextView);
actv.setThreshold(1);//will start working from first character
actv.setAdapter(adapter);//setting the adapter data into the AutoCompleteTextView
actv.setTextColor(Color.RED);
ImageView findBeach = (ImageView) findViewById(R.id.find_beach);
findBeach.setOnClickListener(new View.OnClickListener() {
#Override
** public void onClick(View view) {
AutoCompleteTextView actv = (AutoCompleteTextView) findViewById(R.id.autoCompleteTextView);
String choice = actv.getText().toString();
Log.i("Answer",choice);
if (choice == "one"){
Intent firstIntent = new Intent(paralActivity.this, nauagioActivity.class);
startActivity(firstIntent);
}else if (choice == temp[1]){
Intent secondIntent = new Intent(paralActivity.this, gerakasActivity.class);
startActivity(secondIntent);
}else if (choice == temp[2]){
Intent thirdIntent = new Intent(paralActivity.this, limnionasActivity.class);
startActivity(thirdIntent);
}else{
Toast.makeText(paralActivity.this,"wrong",Toast.LENGTH_SHORT).show();
}
}
});
}
});
}
}
To help u understand, in this activity a have 2 imageViews. When the user presses the second, a relativeLayout appears (with an AutoCompleteTextView and a button inside). After the user writes the word when presses the button it must go to the specific activity. I declared a String Array (temp[3]) with three words inside and 3 activities for each of the words.
The problem starts in the last onclick method that i put ** . Every time i put a correct word from the Array i take the Toast message but in the log i see the correct.
here is Activity.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/activity_paral"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#drawable/main"
android:scaleX="2"
tools:context="com.example.billy.zakynthosapp.paralActivity">
<TextView
android:id="#+id/categories"
android:layout_width="200dp"
android:layout_height="wrap_content"
android:layout_below="#+id/welcome"
android:text="#string/categories"
android:textAlignment="center"
android:layout_centerHorizontal="true"
android:layout_marginTop="30dp"
android:textSize="11sp"
android:textStyle="bold"
android:textColor="#color/welcome"
android:textAllCaps="true"/>
<ImageView
android:id="#+id/aktoploika"
android:layout_centerHorizontal="true"
android:layout_width="130dp"
android:layout_height="50dp"
android:layout_below="#id/categories"
android:layout_marginTop="35dp"
android:scaleType="centerCrop"
android:src="#drawable/par1" />
<TextView
android:id="#+id/aktoploika_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/aktoploika"
android:layout_alignTop="#+id/aktoploika"
android:layout_alignRight="#+id/aktoploika"
android:layout_alignBottom="#+id/aktoploika"
android:layout_margin="1dp"
android:gravity="center"
android:text="#string/paralies"
android:textSize="22sp"
android:textColor="#color/categories"
android:textStyle="bold"/>
<ImageView
android:id="#+id/aeroporika"
android:layout_centerHorizontal="true"
android:layout_width="130dp"
android:layout_height="50dp"
android:layout_below="#id/aktoploika"
android:layout_marginTop="35dp"
android:scaleType="centerCrop"
android:src="#drawable/par2" />
<TextView
android:id="#+id/aeroporika_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/aeroporika"
android:layout_alignTop="#+id/aeroporika"
android:layout_alignRight="#+id/aeroporika"
android:layout_alignBottom="#+id/aeroporika"
android:layout_margin="1dp"
android:gravity="center"
android:text="#string/search"
android:textSize="22sp"
android:textColor="#color/categories"
android:textStyle="bold" />
<RelativeLayout
android:id="#+id/find"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#id/aeroporika"
android:layout_marginTop="50dp"
android:layout_centerInParent="true"
android:background="#color/categories"
android:scaleX="0.5">
<TextView
android:id="#+id/textView_1"
android:layout_width="wrap_content"
android:gravity="center_vertical"
android:textSize="20sp"
android:layout_centerHorizontal="true"
android:text="#string/find_paral"
android:textColor="#android:color/black"
android:textAppearance="?android:attr/textAppearanceMedium"
android:layout_height="wrap_content" />
<ImageView
android:id="#+id/find_beach"
android:layout_width="40dp"
android:layout_height="40dp"
android:layout_centerVertical="true"
android:layout_marginLeft="200dp"
android:src="#drawable/find"
android:onClick="find"/>
<AutoCompleteTextView
android:id="#+id/autoCompleteTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#id/textView_1"
android:layout_marginTop="10dp"
android:ems="10"
android:text="">
<requestFocus />
</AutoCompleteTextView>
</RelativeLayout>
Can anyone help me with this?
Thanks a lot!

Try choice.equals("one") instead of choice == "one"

A lot activity in one layout

I am developing Restaurant menu app. I have 9 image button in activity_main.xml. For example: If when i clicked soup image button, the app will soup price and soup image in other layout. But i dont want create 9 layouts file for this. All of prices appear one layout. I didnt write method for this. I am waiting your help. Sorry for my bad english.
This is my menu.
<ImageButton
android:layout_width="130dp"
android:layout_height="170dp"
android:id="#+id/imageButton2"
android:layout_gravity="left|top"
android:background="#drawable/corbalar"
android:contentDescription="#string/corbalar"
android:clickable="true"
android:onClick="degistirActivity"/>
<ImageButton
android:layout_width="130dp"
android:layout_height="170dp"
android:id="#+id/imageButton3"
android:layout_gravity="center_horizontal|top"
android:background="#drawable/zeytinyaglilar"
android:contentDescription="#string/zeytinyaglilar"
android:clickable="true"
android:onClick="degistirActivity"/>
<ImageButton
android:layout_width="130dp"
android:layout_height="170dp"
android:id="#+id/imageButton4"
android:layout_gravity="right|top"
android:background="#drawable/spesiyaller"
android:contentDescription="#string/spesiyaller"
android:clickable="true"
android:onClick="degistirActivity"/>
<ImageButton
android:layout_width="130dp"
android:layout_height="170dp"
android:id="#+id/imageButton5"
android:layout_gravity="left|center_vertical"
android:background="#drawable/pideler"
android:contentDescription="#string/pideler"
android:clickable="true"
android:onClick="degistirActivity"/>
<ImageButton
android:layout_width="130dp"
android:layout_height="170dp"
android:id="#+id/imageButton6"
android:layout_gravity="center"
android:background="#drawable/salatalar"
android:contentDescription="#string/salatalar"
android:clickable="true"
android:onClick="degistirActivity"/>
<ImageButton
android:layout_width="130dp"
android:layout_height="170dp"
android:id="#+id/imageButton7"
android:layout_gravity="right|center_vertical"
android:background="#drawable/kebaplar"
android:contentDescription="#string/kebaplar"
android:clickable="true"
android:onClick="degistirActivity"/>
<ImageButton
android:layout_width="130dp"
android:layout_height="170dp"
android:id="#+id/imageButton8"
android:layout_gravity="left|bottom"
android:background="#drawable/tatlilar"
android:contentDescription="#string/tatlilar"
android:clickable="true"
android:onClick="degistirActivity"/>
<ImageButton
android:layout_width="130dp"
android:layout_height="170dp"
android:id="#+id/imageButton9"
android:layout_gravity="center_horizontal|bottom"
android:background="#drawable/mesrubatlar"
android:contentDescription="#string/mesrubatlar"
android:clickable="true"
android:onClick="degistirActivity"/>
<ImageButton
android:layout_width="130dp"
android:layout_height="170dp"
android:id="#+id/imageButton10"
android:layout_gravity="right|bottom"
android:background="#drawable/sicakicecekler"
android:contentDescription="#string/sicakicecekler"
android:clickable="true"
android:onClick="degistirActivity"/>
This is the place I'll show information.
<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:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
tools:context="tr.edu.fatih.nad0.com.kilislimenu.fiyatGoster">
//my items image
<ImageButton
android:layout_width="250dp"
android:layout_height="250dp"
android:id="#+id/imageButton11"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true"
android:contentDescription="#string/gosterilecekyemek" />
//my items price
<TextView
android:layout_width="200dp"
android:layout_height="50dp"
android:id="#+id/textView"
android:layout_below="#+id/imageButton11"
android:layout_centerHorizontal="true" />

What you'll want to do is use an intent with extras to pass information of the clicked item to the activity. There's a couple of ways to do this:
1) Manually create an OnClickListener for each item (ideally, you'd generate your items from a SQLite database rather than having a static list).
Using an OnClickListener would look something like this:
ImageButton myButton = (ImageButton) findViewById(R.id.myButton);
myButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent priceIntent = new Intent(getApplicationContext(), priceActivity.class);
priceIntent.putExtra("price",6.99);
priceIntent.putExtra("name","Hamburger");
startActivity(priceIntent);
}
});
Then in your onCreate method for priceActivity.class, you'd read the values like this:
Bundle extras = getIntent().getExtras();
double price = extras.getDouble("price");
String name = extras.getString("name");
2) Use the onClick attribute in your XML to process the information through an identifying tag or some such.
In your XML you can specify android:onClick="myMethod" as well as an identifying tag, like android:tag="hamburger". Then you'd make your myMethod:
public void myMethod(View v) {
String tagId = v.getTag().toString();
// Create intent with extras like above
}
Again, ideally you'd be loading all of this information from a database so that you can easily access the information with fewer methods rather than manually entering the hard-coded data straight into the app.

you can follow below link to workout with your problem.
http://developer.android.com/training/basics/firstapp/starting-activity.html
Alternatively,
you can implement method like this on your button.
public void sendMessage(View view) {
Intent intent = new Intent(this, DisplayMessageActivity.class);
EditText editText = (EditText) findViewById(R.id.edit_message);
String message = editText.getText().toString();
intent.putExtra(EXTRA_MESSAGE, message);
}
On another Activity, you can receive Intent and Display your price.
Intent intent = getIntent();
String message = intent.getStringExtra(MyActivity.EXTRA_MESSAGE);
// Create the text view
TextView textView = new TextView(this);
textView.setTextSize(40);
textView.setText(message);
// Set the text view as the activity layout
setContentView(textView);

OnClickListener on non-Mainactivity & change first activity

i've a problem. I want to make a app with a loggin activity and a main activity. (To the OnClickListiner later)
fist:
What ive done so far:
i've created a login. java and login.xml
login.java:
public class Login extends Activity implements OnClickListener {
Button btnStartAnotherActivity;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.login);
boolean hasLogedIn = true;
if (hasLogedIn) {
Intent i = new Intent(Login.this, MainActivity.class);
startActivity(i);
finish();
} else {
}
}
public void onClick(View view) {
//calling an activity using <intent-filter> action name
Intent inent = new Intent("android.name.MainActivity ");
startActivity(inent);
}
}
i've created a MainActivity.java and activity_main.xml
moreover i've some other java and xml files to make a materiel designed Tab view for my MainActivity.
i have 3 tabs thats how it looks so far
[![tab1 with buttons][1]][1]
-now i'be added to the first tab 3 buttons.
example of one button: (the others are the same just a other id )
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Kommt"
android:clickable="false"
android:textColor="#190707"
android:id="#+id/kommt"
android:layout_alignParentStart="true"
android:layout_below="#+id/space" />
-So the app is running now without problems. ( All Tabs and there content is showing like i want it )
when i build the project the mainactivity is open first( see that link of the picture )
HOW TO SET: the login interface to be started once, when starting the app for the first time. After login is succesfully, then the mainactivity will always open. Thats my first problem. What should i add to the Login.java ? and how to set that the login.xml starts before the mainactivity ?
Second:
As i told you ive added some buttons. To test the buttons i've tried to implement a code for toast notification when clicking on button. But every time i build the project with the toast notifitcation code, the app doenst start anymore. Here the code for the toast notification i'm using:
public class MainActivity extends ActionBarActivity implements OnClickListener {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main); // but my main_activity doesnt have buttons ... tab1.xml have b
Button kommtbutton;
kommtbutton= (Button) findViewById(R.id.kommt);
kommtbutton.setOnClickListener(this);}
#Override
public void onClick(View v) {
setContentView(R.layout.tab1); // not sure if this is right ive did it cause the buttons are in the tab1 layout and not main_activity
switch(v.getId())
{
case R.id.kommt:
{
Toast toast1 = Toast.makeText(getApplicationContext(),
"Eingestempelt",
Toast.LENGTH_SHORT);
toast1.show();
break;
} ....}
here i have implemented all 3 buttons in a switch case.
It looks right but the onclicklistinier seems to kill my application before it can start. Maybe someone can help me.
i have following files:
Login.java, MainActivity.java, Tab1.java,Tab2.java,Tab3.java, SlidingTabsLayout.java, SlidingTabStrip.java and ViewPagerAdaper.
and i have this layouts.
acitivy_main.xml, login.xml, tab1,tab2,tab3.xml, toolbar.xml.
I'm not allowed to send pictures cause i'm new here.
Where have i do implement the code for the toast notification ?
thats my activity_main:xml
<LinearLayout 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="vertical"
tools:context=".MainActivity">
<include
android:id="#+id/tool_bar"
layout="#layout/tool_bar"
android:layout_height="wrap_content"
android:layout_width="match_parent"
/>
<android_package.SlidingTabLayout
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:elevation="2dp"
android:background="#color/ColorPrimary"/>
<android.support.v4.view.ViewPager
android:id="#+id/pager"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:layout_weight="1"/>
and this is my tab1.xml
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/Tabs"
android:background="#FDFDFE"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:id="#+id/buchungen"
android:textColor="#190707"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Geht"
android:clickable="false"
android:textColor="#190707"
android:id="#+id/geht"
android:layout_alignParentBottom="true"
android:layout_alignEnd="#+id/textClock"
android:layout_marginBottom="36dp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Name:"
android:paddingBottom="7dp"
android:paddingTop="7dp"
android:textColor="#190707"
android:id="#+id/name"
android:layout_alignParentStart="true"
android:layout_below="#+id/buchungen" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#190707"
android:paddingBottom="7dp"
android:paddingTop="7dp"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Status:"
android:id="#+id/status"
android:layout_below="#+id/name"
android:layout_alignParentStart="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#190707"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Letzte Buchung:"
android:paddingBottom="4dp"
android:paddingTop="7dp"
android:id="#+id/letzteBuchung"
android:layout_below="#+id/status"
android:layout_alignParentStart="true" />
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_alignBottom="#+id/buchungen"
android:weightSum="1"
android:id="#+id/linearLayout">
<ImageView
android:layout_width="314dp"
android:layout_height="310dp"
android:id="#+id/profilbild"
android:layout_gravity="center_horizontal"
android:src="#drawable/time" />
</LinearLayout>
<Space
android:layout_width="20dp"
android:layout_height="20dp"
android:layout_above="#+id/geht"
android:id="#+id/space" />
<TextClock
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#190707"
android:id="#+id/textClock"
android:layout_alignTop="#+id/name"
android:layout_alignParentEnd="true" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Kommt"
android:clickable="false"
android:textColor="#190707"
android:id="#+id/kommt"
android:layout_alignParentStart="true"
android:layout_below="#+id/space" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceSmall"
android:text="Pause An/Aus"
android:textColor="#190707"
android:id="#+id/textView"
android:layout_alignTop="#+id/textView3"
android:layout_alignStart="#+id/pause" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceSmall"
android:text="Einstempeln"
android:textColor="#190707"
android:id="#+id/textView2"
android:layout_above="#+id/kommt"
android:layout_alignParentStart="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceSmall"
android:text="Ausstempeln"
android:textColor="#190707"
android:id="#+id/textView3"
android:layout_alignBottom="#+id/geht"
android:layout_alignStart="#+id/geht"
android:layout_alignTop="#+id/textView2" />
<ToggleButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Pause"
android:textColor="#190707"
android:id="#+id/pause"
android:layout_alignBottom="#+id/kommt"
android:layout_centerHorizontal="true"
android:checked="false" />
</RelativeLayout>
The buttons are in the tab1.xml. Where have i to acces them to make a Interaction ( show toast when pressing the button ) ? in the MainActivity.java or the Tab1.java or somewhere else ?
When i try to add toast notification my app just kills itself ...

You have to put all the findViewById and setContentView in the onCreate method or they won't do the job.
First point :
public class MainActivity extends ActionBarActivity
{
// Layout elements
private Button kommtbutton = null;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
// Attach layout
setContentView(R.layout.activity_main); // but my main_activity doesnt have buttons ... tab1.xml have b
// Retrieve layout elements
kommtbutton= (Button) findViewById(R.id.kommt);
// Attach listeners
kommtbutton.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View view)
{
// Do not use getApplicationContext(), this is an activity
Toast.makeText(MainActivity.this, "Eingestempelt", Toast.LENGTH_SHORT).show();
}
});
}
[...]
}
Second point :
public class LoginActivity extends Activity
{
// Layout elements
private EditText edit_login = null;
private EditText edit_password = null;
private Button btn_login = null;
// Class variables
private SharedPreferences prefs = null;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
// Check if the user is already logged in
prefs = getSharedPreferences(getPackageName(), MODE_PRIVATE);
if (prefs.getBoolean("isLoggedIn", false))
{
Intent intent = new Intent(LoginActivity.this, MainActivity.class);
startActivity(intent);
finish();
return;
}
// Attach layout
setContentView(R.layout.login);
// Retrieve layout elements
edit_login = (EditText) findViewById(R.id.edit_login);
edit_password = (EditText) findViewById(R.id.edit_password);
btn_login = (Button) findViewById(R.id.btn_login);
// Attach listeners
btn_login.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View view)
{
// Retrieve information
String login = edit_login.getText().toString();
String password = edit_password.getText().toString();
// Do job
boolean canConnect = true; // TODO
if (canConnect)
{
// Update prefs
prefs.edit().putBoolean("isLoggedIn", true).commit();
// Move to activity
Intent intent = new Intent(LoginActivity.this, MainActivity.class);
startActivity(intent);
finish();
}
else
{
// Update prefs
prefs.edit().putBoolean("isLoggedIn", false).commit();
// Display error message
Toast.makeText(LoginActivity.this, "Wrong crendentials", Toast.LENGTH_LONG).show();
}
}
});
}
}

android.widget.imagebutton cannot be cast to android.widget.button Message

Hi I am getting this message android.widget.imagebutton cannot be cast to android.widget.button (See attachment pic for logcat error) which I don't understand why? because my code seems to be right.
Code:
ImageButton Calendar = (ImageButton) findViewById (R.id.Calendar);
Calendar.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent OpenCalendarbtn = new Intent (Menu.this, DisplayCalendar.class);
startActivity (OpenCalendarbtn);
}
});
Complete Layout xml file:
`
<ImageButton
android:id="#+id/Read"
android:layout_width="100dp"
android:layout_height="100dp"
android:layout_alignParentRight="true"
android:layout_alignTop="#+id/Write"
android:layout_marginRight="31dp"
android:src="#drawable/read" />
<ImageView
android:id="#+id/AppLogo"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:src="#drawable/logo" />
<ImageButton
android:id="#+id/Write"
android:layout_width="100dp"
android:layout_height="100dp"
android:layout_alignParentLeft="true"
android:layout_below="#+id/AppLogo"
android:layout_marginLeft="35dp"
android:layout_marginTop="14dp"
android:src="#drawable/write" />
<ImageButton
android:id="#+id/Calendar"
android:layout_width="100dp"
android:layout_height="100dp"
android:layout_alignLeft="#+id/Write"
android:layout_below="#+id/Write"
android:layout_marginTop="20dp"
android:src="#drawable/calendar/>
`

Make sure you have used the <ImageButton> tag instead of <Button> tag in your layout resource file.
That could be the cause of the error.

Change your
ImageButton Calendar = (ImageButton) findViewById (R.id.Calendar);
To:
Button Calendar = (Button) findViewById (R.id.Calendar);

Its an Eclipse problem not in your code.
Solution for this is just copy your code in xml by Ctrl+c and save the xml then again paste it again then save it and run.....this works with me.