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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 }

Custom permission in Android

I'm trying to figure out how to work with custom permissions in Android.
https://developer.android.com/guide/topics/manifest/manifest-intro.html#perms .
I found similar problems answered here but none of the answers worked for me...
I've created simple app with Android studio 2.1.1
package com.example.lukas.permtest;
import android.app.Activity;
import android.os.Bundle;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
}
with manifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.lukas.permtest">
<permission android:name="com.example.lukas.permission.ACTIVITY_PERM"
android:label="#string/permlab_activity"
android:description="#string/permdesc_activity"
android:protectionLevel="normal"/>
<uses-permission android:name="com.example.lukas.permission.ACTIVITY_PERM"/>
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity android:name=".MainActivity"
android:permission="com.example.lukas.permission.ACTIVITY_PERM">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
I have Sony Xperia Z2 tablet with Andoid 4.4.2 and Xperia Z3+ With Android 6.0
The app doesn't work. I get the same exception for both devices...
W/ActivityManager: Permission Denial: starting Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.lukas.permtest/.MainActivity } from ProcessRecord{44cf1178 2461:com.sonyericsson.home/u0a95} (pid=2461, uid=10095) requires com.example.lukas.permission.ACTIVITY_PERM
What am I doing wrong?
Thanks

Hah! That's pretty funny!
I believe that what is going on here is that, although you've done everything right as far as your process and the permission, you forgot one small thing...
The Launcher needs to start your app. The Launcher doesn't have your custom permission.
In other words, your application could launch its own MainActivity, because it has the permission to do so. The Launcher does not have the permission, so when it attempts to launch the android.intent.action.MAIN Activity, if fails for lack of permission.
Separate the Main Activity from the Activity protected by the permission. Launch the protected Activity from the Main Activity and everything go smooth as silk.

Does Android need a default layout file called activity_main.xml

I'm an Android noob and I'm having difficulty finding out something basic about Android.
I currently have an activity_main.xml file.
I want to use this layout when I first start the Android emulator, using Android Studio
Does Android look for a file activity_main.xml and use it as the default layout?
Here's my AndroidManifest.xml:
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
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>
</application>
So I understand that this specifies that my .MainActivity will respond to an action.MAIN intent call. What I don't know is what the action.MAIN intent call actually is, and how my activity_main.xml relates to this.
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
}
Can anyone provide an explanation or a link to a good primer that explains these basic concepts?

From manifest :
<action android:name="android.intent.action.MAIN" />
Means this activity is the entry point of the application. In your case, the MainActivity starts.
The MainActivity sets up the layout for itself - the line responsible is
setContentView(R.layout.activity_main);
Where it looks for layout file activity_main.xml. This is just the naming convention - feel free to rename the layout file and call the new one from setContentView. It's not required to be called activity_main

Android Emulator is running properly but cannot see application on it [closed]

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I am a newbie to android development and have little experience of eclipse. My android emulator is working properly but I cannot see application running on it.
Any pointers would be great. Thanks in advance.
MainACtivity.java
package com.example.helloworld;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
#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;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.act`enter code here`ion_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.helloworld"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="20" />
<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="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>

use the
AndroidManifest.xml
file, you can actually even have more than one launcher activity specified in your application manifest. To make an activity seen on the launcher you add these attributes to your activity in the manifest
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
set this inside your <activity> . hopefully it should work now. :)

Android App - disappearance of app GUI

I'm trying to create a simple app, whose main task is to open the browser on defined URL.
I've created first Activity:
public class MyActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.main);
Intent myIntent = new Intent(Intent.ACTION_VIEW,
Uri.parse("http://my.url.tld"));
startActivity(myIntent);
}
Here's my AndroidManifest.xml:
<manifest ...>
<application ...>
<activity android:name=".MyActivity" ...>
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
This code is fully functional, but before it opens the browser, it displays a black background - blank app GUI. I didn't figured out, how to go directly do the browser (without displaying the GUI).
Anyone knows?

Add this theme declaration to your activity definition in you manifest
<activity android:name=".MyActivity"
android:theme="#android:style/Theme.Translucent.NoTitleBar"
>
Be careful with this, you must call finish(); from your activity after you are done with it otherwise users could get stuck with an invisible activity that prevents them from interacting the phonetop.