Develop Reference

How to choose an activity as a starter activity while launching an app?

I come up with a strange problem while trying to set "SignUpActivity" as my starter activity. I tried different ways but either I am getting an error or "mainActivity" is popping up as a starter activity.
My "AndroidManifest.xml" file has the following code.
<activity
android:name=".SignUpActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
<action android:name="android.intent.action.VIEW" />
</intent-filter>
</activity>
<activity
android:name=".MainActivity" />
the above code gives me the error as shown in image
As the error states activity must be exported or contain an intent-filter
so, I did
<activity
android:name=".MainActivity"
android:exported="true"/>
and also tried adding intent-filter to activity. Of course, these methods make error go away but my app starts with MainActivity, not with SignUpActivity. What should I do to slove this issue?

Your AndroidManifest.xml is set correctly, check your run/debug configuration is set to 'App', not 'MainActvity'
If the 'App' configuration is missing - you will need to add it by first selecting 'Edit Confurations'
There are similar posts about this error msg.

Check the run configuration , probably you need to edit the app configuration and choose it to run.

As guided by #Eric I selected an option "app" from the run configuration which solved my problem. Previously, somehow it was set to MainActivity which was causing the issue. I have attached an image to demonstrate the solution for future readers.

How to run a certain activity in Android Studio?

For instance, I have a few activities within one app, and in order to see a certain activity's UI or whatever, I need to run a certain activity that is not the launcher of the app.
One stupid way is to build a "door" for that activity in the launcher and go inside the activity from the door. However, Is there any better way to run a certain activity alone?

Very easy. Start by exporting the activity you need to run:
Add android:exported="true" in the Activity declaration in the Manifest. This is because am is an external application, and you need to export Activities to allow external application to start them.
Go to "Edit Configurations..." in the "Run" menu.
In the left pane, select your application. In the right pane, in the "General" tab, in the "Launch Options" section, there is a "Launch:" dropdown.
Select "Specified Activity", and enter the name of your activity as it appears in your Manifest.
You can create as many Configurations as you like, and name them according however you like, for example to indicate which activity is being started.

I am using Android Studio stable version 2.1.2 and there is one shortcut to do so. Just open the activity class you wish to run and right click on coding area, There is options to run and debug the particular activity as shown in below screen shot.
For windows use shortcut ctrl+shift+F10 and for mac use ctrl+shift+R. I have tested this in emulator and its working fine, didn't test in actual device.Works only for activity class and don't forget to put cursor in coding area by clicking on it. Also I am not aware whether this option available in older Android studio versions less than 2.1.2.

As mentioned in this answer, you can easily achieve that by giving the activity an action name in the manifest.xml of the app:
<activity android:name="Activity3" ... >
<intent-filter>
<action android:name="com.company.package.FOO"/>
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
then create the following intent from anywhere in order to run this activity specifically:
startActivity(new Intent("com.company.package.FOO"));
After your clarification that the activity has to be run firstly when running the app instead of the launcher, you can achieve that by not setting the content of the launcher activity and instead create an intent that runs the wanted activity:
MainActivity:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.activity_layout); // remove this line
Intent intent = new Intent(ThisActivity.this, WantedActivity.class);
intent.putExtra("EXIT", false);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
}

Add exported true Manifest declaration of that activity.
Go to that activity, right click anywhere, go will get certain option with a 'Run XYZ Activity' option too. just run it

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

First you need to have two or more activities in your app to start with. Let's say you want to go to a certain activity in your app to display first. May be for testing purposes or any other. Let's see how it can be done,
First you need to find the AndroidManifest.xml file. Its there under the manifests folder.
According to this first dispaly activity is MainActivity
Lets's say I want to make the home activity display first. So what I have to do is simply cut the intent-filter.../intent-filter and paste it within home activity. Like this
First Displaying Acivity is MainActivity according to this,
<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=".home">
</activity>
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
When we want to make the home acivity display first simplay change it as this,
<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=".home">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".MainActivity">
</activity>
</application>
This should work. Hope this will help

For my example, the specific activity was called Activity2 and the project was called ScreenSizes
1- Open the Android Manifest: app>manifests>AndroidManifest.xml
2- Change the activity section for the specific activity to include android:exported="true" like this:
<activity android:name=".Activity2"
android:exported="true">
</activity>
3- Open the java class of the specific activity: app>java>com.example.(your app name)>(specific activity)
in my case it was: app>java>com.example.screensizes>Activity2
4- Right click anywhere in the blank/white area of the Java file and select the option Run '(activity name)'
in my case it was: Run 'Activity2'

MyFirstApp installed on emulator but can't launch it

I'm going through the Android 'Building Your First App' tutorial and have gotten stuck trying to run the app. I created the app and emulator with Eclipse (Juno Build id: 20120920-0800 on OS X, default installation. The Android SDK, etc. was updated today).
The app appears to be installed on the emulator. I.e. 'Home -> Menu -> Manage Apps' lists it and it's App info looks ok. (Total=24.00KB, App=24.00KB, USN storage app=0.00B, ...).
However, it does not appear in the apps launch list (i.e. the screen with 'API Demos', 'Browser', etc.
Is there some other way to launch it? Is there something I have to do to get it into the app list? Any help would be appreciated - this is driving me crazy.
thanks

In your manifest xml file you need to make sure that you have
<intent-filter >
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
in your activity definition. If you don't see your application in the launcher then it suggests you don't have "android.intent.category.LAUNCHER" set.
Your manifest file should have something like (this isn't a complete manifest)
<application android:icon="#drawable/icon" android:label="#string/app_name">
<activity android:name=".MyActivity"
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>
You can't just put the intent-filter lines in your manifest. If you double click the manifest it will open up. You get 2 methods to edit it, raw XML or using a basic interface. Personally I think you're better off with the raw interface. Look below the window that opens when you double click the manifest, you'll see some tabs like Manifest, Application... the last on is AndroidManifest.xml - this is the raw xml. The first one is basic setup.
Don't forget to save your manifest file and do a clean and build then run it.

Launching given activities directly

I'd like to create run configurations within Eclipse to launch a given Android activity directly so I don't have to run through my entire application to get to it. In my manifest, I've declared the activity like so:
<activity
android:name=".AlternativeActivity"
android:label="#string/title_alternative_activity"
android:exported="true">
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="com.mysite.AlternativeActivity" />
<intent-filter>
<action android:name="android.intent.action.MAIN" />
</intent-filter>
</activity
However, in Eclipse, I'm seeing the following warning:
Exported activity does not require permission.
How do I resolve this warning?

Exported activities (activities which either set exported=true or
contain an intent-filter and do not specify exported=false) should
define a permission that an entity must have in order to launch the
activity or bind to it. Without this, any application can use this
activity.
Protip: Place your cursor on the warning, press CTRL + 1 and select "Explain Issue".

Eclipse- creating new Activity

I have problem when I create a new Android project. I fill in the name of the app and the package name, then I go to the next scrren and set the icon. On the following scrren I select Blank activity and hit next when this screen appears:
I enter everything, but i donť know what to do with Hierarchical Parent. A few days ago it worked perfectly, but now when I chose something from list on the left, and create activity, eclipse unless I wrote something says it's wrong.
Can anyone help me?

For an Activity set it to android.app.activity.

I got the same problem like yours. After a day, I found the way.
It's very simple. re install the ADT Plugin:
In Eclipse, Help > Install New Software....
Click Add, in the top-right corner.
Enter "ADT Plugin" for the Name and URL = http://dl-ssl.google.com/android/eclipse/
Then just enter until finish
For the full tutorial how to instal ADT Plugin you can look at:
http://developer.android.com/sdk/installing/installing-adt.html

Your error concerns the name of the activity verify the project build sdk
the hierarchical parent activity is used normally to provide a default implementation for the UP button

1.Copy your Package Name, then past to "Hierarchical Parent" Field.
(any words to skip this step)
2.AndroidManifest.xml need an "android.intent.action.MAIN" for start.
Add follow source code
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
like this：
<application
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".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>

Platform-tools version 14 has this problem, but not version 13.
http://dl-ssl.google.com/android/repository/platform-tools_r13-linux.zip
I backed up my current (problematic) /android-sdk/platform tools, deleted the old folder and replaced it with ver 13, started eclipse, reset the android-sdk path (windows>preferences>android, don't forget to click "apply") and recreated my AVD.
Version 13 also has the heirarchical parent text box, but it's optional.

The problem is a bug with the Application Wizard... which tries to integrate the Activity Wizard within itself. The problem is that the integrated Activity Wizard doesn't work correctly without there being an existing project.
Therefore, an easy solution to this problem is from the Project Wizard, just create a basic main activity with "none" for navigation type and click "finish". Then once the project has been created, use the Activity Wizard to create your desired main Activity.
As a bonus, the Activity Wizard will even refactor the code to use this new Activity as your main Activity!