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"App has stopped" when changing between activities

Hello everyone this is my first android coding and im trying to switch between activities, but i cant simply find where is my mistake.
Main here;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
protected void start()
{
Intent k= new Intent(MainActivity.this, Try.class);
startActivity(k);
finish();
}
And My manifest is here and my second activity name is "Try";
<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=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name="com.example.ege.intent.Try"
android:label="#string/app_name" >
</activity>
</application>
Thanks.

I think;
May your class package name is wrong but there should be more information about crash.
Change android:name="com.example.ege.intent.Try"
with Try.class location, if it is same in Manifest.
Just try to Change android:name=".Try"
If you put your error or your log details, I can help you

the method "start()" is unused. use it in "onCreate()" method .
you may add a button . swtich activities by listening the click.

Where do you call start()?. Manifest seems okay but check if your package is right, anyway try would do the same, MainActivity lacks a closing semicolon }

How to stop an activity from reloading on orientation changes

I have an activity as a child within a navigation drawer parent activity, any time the orientation of the pages changes the page has to be reloaded again.
public class ApplicationsClass extends NavigationDrawer implements LoaderCallbacks<Cursor> {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getLayoutInflater().inflate(R.layout.main_list_activity, frameLayout);
if (savedInstanceState == null) {
//I do my stuffs here
}
}
...
}
In my AndroidManifest.xml
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="22" />
<!-- Main activity. -->
<application
android:largeHeap="true"
android:allowBackup="true"
android:theme="#style/AppTheme"
android:configChanges="orientation|keyboard|keyboardHidden|screenSize|screenLayout|uiMode">
<!-- Register Activity -->
<activity
android:name=".ApplicationsClass">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
...
</application>
I have tried adding android:configChanges="orientation|keyboard|keyboardHidden|screenSize|screenLayout|uiMode" to my application tag in the androidmanifest as some articles suggested but to no avail. Please is there a way to stop reloading the page upon orientation changes in android. I would be grateful if someone could help. Thanks in advance.
UPDATE
I had also tried adding android:configChanges="orientation|screenSize" to my activity within the androidmanifest.xml but to no avail.
I just realized that adding android:configChanges="orientation|screenSize|keyboardHidden" only works when i am had not extended the class from the navigationdrawer and thereby making it a fragment with the navigationdrawer class. This only works when it is not in a fragment layout form.

You need to declare android:configChanges="orientation|screenSize" in activity tag not in application tag
<activity
android:name=".ApplicationsClass"
android:configChanges="orientation|screenSize">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>

No activity found to handle Intent/no launcher activity found manifest file issue

Here's the problem guys, first i tried to run my application with Launch default activity as launch action (Run Configurations --> Android --> Launch action), the logcat kept telling me that it can't find the launcher activity and the application wouldn't even start, problem is i defined my launcher activity in the manifest file, but it's like it's not reading it at all.
So i tried to launch the splash activity by specifically telling it to run it through run configurations, it did launch but during the transition to the next activity it crashed again, the logcat says no activity found to handle intent, which again, I defined the way I did in other applications and worked alright there. Plase help it's a nightmare.
Here's the code for the MainActivity:
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Thread timer = new Thread()
{
public void run(){
try{
sleep(6000);
} catch (InterruptedException e){
e.printStackTrace();
} finally {
Intent openStarting = new Intent("totaltrainer.com.WorkoutPlace");
startActivity(openStarting);
}
}
};
timer.start();
}
#Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
finish();
}
}
And Manifest:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="totaltrainer.com"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="15" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="totaltrainer.com.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".WorkoutPlace"
android:label="#string/app_name" >
<intent-filter>
<action android:name="totaltrainer.com.WorkoutPlace" />
</intent-filter>
</activity>
<activity
android:name=".WorkoutHome"
android:label="#string/app_name" >
<intent-filter>
<action android:name="totaltrainer.com.WorkoutHome" />
</intent-filter>
</activity>
<activity
android:name=".WorkoutGym"
android:label="#string/app_name" >
<intent-filter>
<action android:name="totaltrainer.com.WorkoutGym" />
</intent-filter>
</activity>
</application>
</manifest>

use "totaltrainer.com.WORKOUTGYM" and so on
and below use this
<category android:name="android.intent.category.DEFAULT" />

Problem 1
logcat kept telling me that it can't find the launcher activity and
the application wouldn't even start
In your Manifest file, change below
<activity
android:name=".MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="totaltrainer.com.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
as
<activity android:name="MainActivity">
<!-- This activity is the main entry, should appear in app launcher -->
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
What happens when you define this Action and Category ?
The ACTION_MAIN action indicates this is the main entry point and does not expect any intent data.
The CATEGORY_LAUNCHER category indicates that this activity's icon should be placed in the system's app launcher. If the element does not specify an icon with icon, then the system uses the icon from the element.
These two must be paired together in order for the activity to appear in the app launcher.
Problem 2
the logcat says no activity found to handle intent
Your Manifest declaration seems fine.
In your activity class, change
Intent openStarting = new Intent("totaltrainer.com.WorkoutPlace");
startActivity(openStarting);
as
Intent openStarting = new Intent();
openStarting.setAction("totaltrainer.com.WorkoutPlace");
startActivity(openStarting);

How does an android program understands which class or/and activity to call first?

As i am new to android programming, I don't know how to call a certain class and/or certain activity first.
For example i have two classes viz. 1) Login.java 2) Create.java and two xml files associated with them are activity_main.xml and create_new.xml respectively.
So how can i make Login.java run first with activity_main.xml as screen?

in login java use this
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);}
in create java us this
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.create_new);
in androidmanifest
<activity
android:name=".Login"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
and another activities
<activity android:name=".MainActivity" ></activity>

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.your.package"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="10"
android:targetSdkVersion="19" />
<uses-permission android:name="android.permission.INTERNET" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.example.your.package.activity.Login"
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.example.your.package.activity.Create"
android:label="#string/app_name" >
</activity>
</application>
</manifest>
In this case, the intent-filter of LOGIN activity specifies that the intent with action of MAIN and category of LAUNCHER will be caught by it, aka it is where the application starts.
Afterwards,
public class Login extends Activity
{
//honestly I'd name this class LoginActivity and same in the XML
#Override
public void onCreate(Bundle saveInstanceState)
{
super.onCreate(saveInstanceState);
setContentView(R.layout.activity_main);
}
....
}
Also look at this example to learn how to use Fragments:
NullPointerException accessing views in onCreate()

from the intent filters you decalre in the android manifest file of your project;see the image
You declare an intent filter in the activity tag something like shown in the image for making it the first activity of your application.and if there are other activities in your app having intent filters than you have to just change the capital letter MAIN to DEFAULT in the intent filter tag
You will find AndroidManifest file like in the following image in your project

Android ActivityNotFoundException

I'm trying to create a very simple custom intent example. I've searched for this error and none of the forums have answers that work for me. Here are my files:
public class DemoImplicit extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
public void whenButtonIsClicked(View view) {
Intent intent = new Intent("com.example.action.NEW_ACTION"); //<<<<<<<
intent.addCategory("android.intent.category.DEFAULT"); //<<<<<<<
// Intent intent = new Intent("android.intent.action.VIEW");
// intent.addCategory("com.example.MY_CATEGORY");
startActivity(intent); //<<<<<<<
}
}
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.demos" android:versionCode="1"
android:versionName="1.0">
<application android:icon="#drawable/icon" android:label="#string/app_name">
<activity android:name=".SatisfyIntent" android:label="#string/app_name">
<intent-filter>
<!-- action android:name="android.intent.action.VIEW" / -->
<!-- category android:name="com.example.MY_CATEGORY" / -->
<action android:name="com.example.action.NEW_ACTION" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
</application>
<uses-sdk android:minSdkVersion="9" />
</manifest>
These two separate files are in two different Eclipse projects, but I make sure to load the project containing the intent-filter onto the emulator before loading the file containing the startActivity call onto the emulator. In any case, I always get an ActivityNotFoundException.
What am I doing wrong?
P.S. Here's the AndroidManifest.xml file for the project containing DemoImplicit.java:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.demos"
android:versionCode="1"
android:versionName="1.0">
<application android:icon="#drawable/icon" android:label="#string/app_name">
<activity android:name=".DemoImplicit"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
<uses-sdk android:minSdkVersion="9" />
</manifest>

Fisrtly you shuld ensure that your AndroidManifest.xml file must have defined the DemoImplicit Activity in this.
As like this:<activity android:name=".DemoImplicit"/>
Also in your code you have aspecified the SatisfyIntent as a launcher Activity
<activity android:name=".SatisfyIntent" android:label="#string/app_name">
But here it seems like you have nothing like this in your Java Code.
So the Bottom line is that: Activity which you want to run must have defined in your AndroidManifest.xml file.