Develop Reference

How to add a Login Page/Activity to a Pre-Existing Main Activity? [duplicate]

I have created the meat and guts of my application but I want to add a different activity that will be the starting point (sort of a log-in screen).
Couple questions:
1 I have a fairly decent handle on how to switch between activities (based on this article: http://www.linux-mag.com/id/7498) but I'm not sure how to go about creating a new one (with eclipse).
2 Once I have a new activity created, how can I set it as the default activity of my application? I presume I could just change the name of the classes...but is there a more elegant way to handle that (maybe within the AndroidManifest.xml)?

Yes, you 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>

Go to AndroidManifest.xml in the root folder of your project and change the Activity name which you want to execute first.
Example:
<activity android:name=".put your started activity name here"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>

If you are using Android Studio and you might have previously selected another Activity to launch.
Click on Run > Edit configuration and then make sure that Launch default Activity is selected.

<application
android:icon="#drawable/YOUR_ICON" <!-- THIS ICON(IMAGE) WILL BE SHOWN IN YOUR APPS -->
android:label="MY APP NAME " > <!-- HERE LABEL(APP NAME) -->
<activity
android:name=".application's starting activity" <!-- (.)dot means current dir, if your activity is in another package then give full package name ex: com.xxx.Activity -->
android:label="LABEL FOR ACTIVITY "
android:screenOrientation="portrait" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>

Follow to below instructions:
1:) Open your AndroidManifest.xml file.
2:) Go to the activity code which you want to make your main activity like below.
such as i want to make SplashScreen as main activity
<activity
android:name=".SplashScreen"
android:screenOrientation="sensorPortrait"
android:label="City Retails">
</activity>
3:) Now copy the below code in between activity tags same as:
<activity
android:name=".SplashScreen"
android:screenOrientation="sensorPortrait"
android:label="City Retails">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
and also check that newly added lines are not attached with other activity tags.

This is easy to fix.
Changes to the Launcher activity are also stored in the Debug configuration.
Go to Run > Debug Configurations and edit the setting.
There is also a similar setting in Intellij under Run > Edit Configurations select Run default Activity and it will no longer save the setting in this fashion.

It's simple. Do this, in your Manifest file.
<activity
android:name="Your app name"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.HOME" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>

<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>

Just go to your AndroidManifest.xml file and add like below
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
then save and run your android project.

You add this you want to launch activity
android:exported="true" in manifest file like
<activity
android:name=".activities.activity.MainActivity"
android:windowSoftInputMode="adjustPan"
android:exported="true"/>
<activity
Open java file of this activity and right click then click on Run 'main Activity'
OR
Open java file of this activity and press Ctrl+Shift+F10.

In a recent project I changed the default activity in AndroidManifest.xml with:
<activity android:name=".MyAppRuntimePermissions">
</activity>
<activity android:name=".MyAppDisplay">
<intent-filter>
<action android:name="android.intent.activity.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
In Android Studio 3.6; this seems to broken. I've used this technique in example applications, but when I use it in this real-world application it falls flat. The IDE once again reports:
Error running app: Default activity not found.
The IDE still showed a configuration error in the "run app" space in the toolbar (yellow arrow in this screenshot)
To correct this error I've tried several rebuilds of the project, and finally File >> "Invalidate Cache/Restart". This did not help. To run the application I had to "Edit Configurations" and point at the specific activity instead of the default activity:

In AndroidManifest.xml
I changed here the first activity to be MainActivity4 instead of MainActivity:
Before:
<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=".MainActivity2" />
<activity android:name=".MainActivity3" />
<activity android:name=".MainActivity4" />
<activity android:name=".MainActivity5" />
<activity android:name=".MainActivity6"/>
After:
<activity android:name=".MainActivity" />
<activity android:name=".MainActivity2" />
<activity android:name=".MainActivity3" />
<activity android:name=".MainActivity4" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".MainActivity5" />
<activity android:name=".MainActivity6"/>

For anyone getting errors in their debug\AndroidManifest.xml file make sure that you include the tag!
"<activity android:name=".MainActivity>"
For example:
<activity android:name=".MainActivity"><intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter></activity>

Creating a new Activity, makes a whole new application?

Im new to android, and when i read "Create New Activity" i was under the impression it creates a new "Window/Layout/Screen".
When i start making my own application i see
Main.java
is one application and
SecondActivity.java
is another app in my Emulators menu?
Why is that and how can i go about making one app with multiple windows as apposed to multiple applications essentially?
Manifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.ryan.bidorbuyapp" >
<application
android:allowBackup="true"
android:icon="#mipmap/bidorbuy_logo"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".FullscreenActivity"
android:configChanges="orientation|keyboardHidden|screenSize"
android:label="#string/app_name"
android:theme="#style/FullscreenTheme" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".SearchResults"
android:configChanges="orientation|keyboardHidden|screenSize"
android:label="#string/title_activity_search_results"
android:parentActivityName=".FullscreenActivity"
android:theme="#style/FullscreenTheme" >
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="com.ryan.bidorbuyapp.FullscreenActivity" />
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
thanks

Look at your AndroidManifest.xml there is the problem. Your activities have Launcher between it's tags. Only one activity must have LAUNCHER tag
Only one activity must have
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>

You should understand what is an Activity before starting to developing an android application. You can think an activity as a page in web. There can be one or more and every activity includes their own contents.
When you create a new activity in your project, you should navigate by doing some operations in another activity. Intent helps you at this point to navigate one activity to the another.
Your problem is that, you should check your AndroidManifest.xml file. Please check the declaration of intent here. I think you will solve it after making a search about Intent.

Installing Android app in a device

I'm a newbie programming for android, I made a simple game some days ago and I tried to install it in a tablet(Android 4.0).
The program works ok, but I got four(4) icons of my app after installation and only one of them is correct(third).
I just want to know how I can to solve this bug so that when I install it in another device it runs ok and get only one icon.
Thanks in advance.

It's because in your manifest you need to change all of your activities EXCEPT your first activity (usually your mainActivity) from:
<activity
android:name=".SecondActivity"
android:label="activity name" >
<intent-filter
android:label="Your App Name">
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
to:
<activity
android:name=".SecondActivity"
android:label="activity name" >
</activity>
Basically just take the intent-filter out of all your activities that are NOT your main activity. Your main activity needs it so that there is a launcher icon. Hope that helps.

I got four(4) icons of my app after installation
means you have declared more then one Activity in AndroidManifest.xml as launch Activity. to show only one Activity as launcher you will need to declare only one Activity with android.intent.action.MAIN and android.intent.category.LAUNCHER intent-filter.
Declare Main Activity which u want to show in Launcher as:
<activity android:name="MainActvity"
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 other 3 Activity declare as in AndroidManifest.xml as :
<activity android:name="Actvity_Two"
android:label="#string/app_name" />
<activity android:name="Actvity_Three"
android:label="#string/app_name" />
//declare other in same way ..

Make home intent take to specific application activity?

I've built a project that contains different packages and activities, say:
com.example.package1.Activity1
com.example.package2.Activity2
The first package holds a launcher. On my project manifest file this activity is listening to the home intent:
// Launcher
<activity android:name=".package1.Activity1" android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.HOME" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
// package2.activity1
<activity android:name=".package2.activity1" android:label="#string/package2_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
My problem is that when a user clicks Home the launcher isn't opened, instead the user is taken to the last opened activity of the app. EG: User opens package2.MainActivity from default launcher > goes to another app > clicks home > package2.MainActivity is opened again.
Is this normal? How do I make sure the device Home button takes to .package1.activity1?

If you are trying to create a HOME-screen replacement, then the activity for that needs to have the following in its <activity> tag in the manifest:
android:launchMode="singleInstance"
This will ensure that only one instance of this activity ever exists and that when this activity launches other activities that they will all go into new tasks and not be a part of the HOME-screen replacement's task.

I am not sure but please try to this code:
// package2.activity1
<activity android:name=".package2.activity1" android:label="#string/package2_name" >
<intent-filter>
<action android:name="android.intent.action.View" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>

How do I make an applcation's launch icon run the preferences activity?

I would like an app's launch icon run the app's preferences activity (as it has no Activities, only a Service).
The preferences are defined in res/xml/preferences.xml.
Please help me regarding this.

you need to create an activity for your preference (PreferenceActivity), add that activity in your manifest and provide appropriate intent-filters as shown below to run through launcher:
<activity android:name=".MyPreferenceActivity" android:label="Preferences" android:noHistory="true">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>