Develop Reference

unable to startActivity master-detail from another activity

I've an activity WelcomeActivity.java in which theres a button bContinue. In the OnClick method of the button, I tried this..
startActivity(new Intent(this, MenuItemDetailActivity.class));
//startActivity(new Intent("com.resto.demo.activity.MENUITEMLISTACTIVITY"));
neither of the above 2 lines work. instead they give me NullPointerException & the program ends abruptly..I cant find the problem.. is the problem in manifest or my call?
<activity
android:name="com.resto.demo.activity.MenuItemListActivity"
android:label="#string/title_menuitem_list" >
<intent-filter>
<action android:name="com.resto.demo.activity.MENUITEMLISTACTIVITY" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
MenuItemListActivity is the part of master/detail flow.
Thanx you. Also tell me if my problem is not understood. Any help/suggestion is welcome :)

Edit your manifest
<application
<activity
android:name="com.resto.demo.activity.MenuItemListActivity"
android:label="#string/title_menuitem_list" >
<intent-filter>
<action android:name="com.resto.demo.activity.MENUITEMLISTACTIVITY" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
<activity android:name="com.resto.demo.activity.MenuItemDetailActivity"/>
</application>
And add this to OnClick event
startActivity(new Intent(MenuItemListActivity.this, MenuItemDetailActivity.class));

The first thing I would do is make sure MenuItemDetailActivity is in the AndroidManifest as well (instead of just MenuItemListActivity)
<activity
android:name="com.resto.demo.activity.MenuItemDetailActivity"
android:label="..." >
</activity>
However, this does not normally throw a NullPointerException. Can you post the error message/stack trace for the NullPointerException? Also, it would be great to post the lines of code that the NullPointerException references.

Android Eclipse Add New Activity

I am using Win 7.0, Eclipse and android SDK. I want to add new activity in AndroidManifest.xml Application tab as it is shown in this tutorial Android Development – Adding Screens & Button Handlers
I add an Activity name to my manifest but it does not automatically turn it into a link. e.g. I cannot click the "Name"(It is not a hyperlink as shown in the article), thus I cannot create my class.
Can You Help me? what is the problem ?

1.Go to the Androidmanifest.xml file and add the activity inside the tag
if your activity name is secondAct.
2.Create a class named secondAct.
<application android:icon="#drawable/icon" android:label="#string/app_name">
<activity android:name=".Project1Activity"
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=".secondAct"></activity>
<activity android:name=".third"></activity>
</application>
3 . if you are using a button for going to next activity, use the following code in secondAct.java
Button fbtn=(Button)findViewById(R.id.sbtn);
fbtn.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
Intent sec=new Intent(secondAct.this,com.asish.third.class);
startActivity(sec);
}
});

Go to the small tab underneath that says AndroidManifest.xml and shows you the XML code for it. It should look like this:
<application android:label="#string/app_name" android:icon="#drawable/icon">
<activity android:name=".ApplicationName"
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=".AnotherActivity"></activity>
</application>
Okay, click on ADD, then select the top box that says "Create a new element at the top level, in Application" and then you should get a box with linkable NAME*.

You need to create the class first, then point to that class in your manifest... just putting the class name in the manifest is not enough. It will not automatically create it for you.
Also, it is easier to create the class first because then Eclipse will autocomplete the class name/path for you.
EDIT: AH HAH! I see what link you are talking about...
Yeah, you need to actually create the class first for that to appear.

Android Custom Intent Cannot Start Activity (Yes, I include the DEFAULT category)

I have searched and searched and cannot seem to find the answer to this specific question about a custom intent.
I have an application with 4 activities, 1 is the main that sets things up and the other 3 represent the different screens I present to the user. I am trying to use custom intents to start the different activities.
Here is my AndroidManifext.xml:
<?xml version="1.0" encoding="utf-8"?>
<application android:icon="#drawable/icon" android:label="#string/app_name">
<activity android:name=".Activities.REDB_main" android:label="#string/app_name"
android:launchMode="singleTop">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".Activities.ChooseCards" android:launchMode="singleTop">
<intent-filter>
<action android:name="#string/ACTION_VIEW" />
<action android:name="#string/ACTION_REFRESH" />
<category android:name="#string/CATEGORY_SHUFFLE" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
<activity android:name=".Activities.SelectSets" android:launchMode="singleTop">
<intent-filter>
<action android:name="#string/ACTION_VIEW" />
<action android:name="#string/ACTION_REFRESH" />
<category android:name="#string/CATEGORY_SELECT_SETS" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
<activity android:name=".Activities.SelectCards" android:launchMode="singleTop"
android:permission="android.permission.ACCESS_CHECKIN_PROPERTIES">
<intent-filter>
<action android:name="#string/ACTION_VIEW" />
<action android:name="#string/ACTION_REFRESH" />
<category android:name="#string/CATEGORY_SELECT_CARDS" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
</application>
I create a category for each application and then the two kinds of actions I want it to handle. I know that I could use explicit intents, but since I want to have different actions I figured that making the implicit intents would work better.
I call the first of my real activities from within my main with this:
Intent intent = new Intent().setAction(getString(R.string.ACTION_VIEW));
intent.addCategory(getString(R.string.CATEGORY_SHUFFLE));
startActivity(intent);
Of course, the reason I am here is because the above can never find the activity that matches the intent. The error messages states the action and category correctly and unless I'm wrong, the above manifest creates the intent-filters correctly.
Searching around online, I always seem to find examples with data also being used. I messed around with adding data just to see if it was necessary but it did not seem to matter.
On a slightly different note, is there a different way I should be controlling the flow of my program besides intents? The reason I have two actions is because 1 switches the view while the other is there to just refresh the data so that when the user switches to the screen later, they don't see it quickly refresh the data but instead just the new stuff.

I know that I could use explicit intents, but since I want to have different actions I figured that making the implicit intents would work better.
I rather doubt that. Mostly you use <intent-filter> when you want things other than your own app to start the component (e.g., third party apps).
Also, I doubt you want android:launchMode="singleTop" on all of those. And I am very certain that you do not want android:permission="android.permission.ACCESS_CHECKIN_PROPERTIES" on the last one, as you won't be able to launch your own activity then, most likely.
The error messages states the action and category correctly and unless I'm wrong, the above manifest creates the intent-filters correctly.
I have never seen an Android application use a string resource for a <category> element. Perhaps that is contributing to your difficulty. Also, since the <category> elements are not doing you any good that I can see (except your LAUNCHER one), I am unclear why you put them there.
I suggest that you just drop the <intent-filter> elements and use explicit Intents.

Don't use resource strings to make intents actions, use android.intent.action.VIEW instead

Android Activity order

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="muazam.multiplication.one"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="3" />
<application android:icon="#drawable/icon" android:label="#string/app_name">
<activity android:label="#string/app_name" android:name=".multiplication">
<intent-filter android:priority="1">
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:label="#string/app_name" android:name=".splash">
<intent-filter android:priority="3">
<action android:name="android.intent.action.CLEARSCREEN" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
<activity android:label="#string/app_name" android:name=".Menu">
<intent-filter android:priority="2">
<action android:name="muazam.multiplication.one.Play" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
</application>
</manifest>
I want it to start with the .splash class first, and then .Menu class.
As you see I have put android:priority on them, but it seem to do nothing.
Anyone know how to solve this problem? Thanks.

I want it to start with the .splash class first
That has no meaning in Android.
If you meant to say "I want the .splash class to be what launches when the icon in the home screen launcher is clicked", then you need to get rid of the .splash class' current <intent-filter> (which is simply wrong) and move your MAIN/LAUNCHER <intent-filter> from the .multiplication class to the .splash class.
While you are at it, please get rid of the android:priority attributes (which are not used here) and your Play/DEFAULT <intent-filter> (which you really should not need, unless you plan on third-party apps starting up that activity directly).
and then .Menu class
You do this in Java code with startActivity().
As you see I have put android:priority on them, but it seem to do nothing.
Of course. There is no android:priority attribute for the <activity> element, as you can see in the documentation.

Activities aren't run automatically like a 'slide show' (although you could write your own code that way if you really wanted to).
The android:priority attribute is used for an entirely different purpose (from the docs for <intent-filter>...
It provides information about how able
an activity is to respond to an intent
that matches the filter, relative to
other activities that could also
respond to the intent. When an intent
could be handled by multiple
activities with different priorities,
Android will consider only those with
higher priority values as potential
targets for the intent.
In other word, if you have two activities each having an intent filter with the same action and category, then any Intent sent (from a 3rd party app) with those action/category details, will be passed first to the Activity whose intent filter has the highest priority.
This has nothing to do with how an app (and its activities) behave internally at runtime.

Android: APK Icon is not being installed

I am able to deploy my application but for some reason, I am not able to get the icon to display in the pull up menu on the Home page of the OS. Does anyone know what I can do to solve this?
By the way, the application shows up in "Manage Applications" but does not show up as an icon for some reason. Through Eclipse, I am able to start the application after deployment but that's it... After that, I don't have any way to start it because there is no icon. :( Following is my manifest file:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.android.ApplicationName"
android:versionCode="1"
android:versionName="2.0">
<application android:icon="#drawable/icon"
android:debuggable="true"
android:label="#string/app_name">
<activity android:name=".EntrySplash"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
<category android:name="android.intent.category.BROWSABLE"></category>
<data android:scheme="com.android.ApplicationName"></data>
</intent-filter>
</activity>
<activity android:name=".EntryScreen" android:label="#string/app_name">
</activity>
<activity android:name=".ApplicationName" android:label="#string/app_name">
</activity>
</application>
<uses-sdk android:minSdkVersion="3" />
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
</manifest>

I had this problem as well, i think the fix that worked for me is i separated the intent tag like below
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
<intent-filter>
<category android:name="android.intent.category.BROWSABLE"></category>
<data android:scheme="com.android.ApplicationName"></data>
</intent-filter>
when i changed my manifest file like that, my icon showed up.

Try getting rid of your android.intent.category.BROWSABLE and <data android:scheme="com.android.ApplicationName"> temporarily, and see if your icon shows up.
Also, on an unrelated matter, I recommend that your uses-* elements be the first children of manifest, not the last. There have been rumors of problems with the XML parsing done by the Android Market, where it wants to see those before any elements.

Had this same issue and found out that one caveat is that this correct intent on the main activity tag:
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
has to be in its own intent filter. you may have other items in the main activity's intent filters, and if so, separate the rest out in to a separate intent filter tag right below it. leave the MAIN and LAUNCHER together in its own.
Alot of the answers to this question on SO seem to miss that point.
Hope it helps!

Well it is happening as you are giving two categories name to your launching activity. You launching activity should have only one category name in its Intent filter. But if you also need the Browsable activity then your Launching Activity may have 2 Intent Filters as show below.
You just replace your EntrySplash Activity code with the below code in you Manifest.xml file.
<activity android:name=".EntrySplash"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
<intent-filter>
<category android:name="android.intent.category.BROWSABLE"></category>
<data android:scheme="com.android.ApplicationName"></data>
</intent-filter>
</activity>
This will sure work for you...

This problem still exists in SDK v2.2. A few more suggestions in addition to the ones above if you want to publish to your phone from Eclipse. Try these if it's still not working and you don't feel like manually publishing. Remove all blank lines in the manifest. And make sure this line just has only icon and label properties in it:
<application android:icon="#drawable/icon" android:label="#string/app_name">

Apparently I found out that it works if I manually install the application using command line adb. So, in case you updated your ADT plugin and you experience problems, just install things manually...

I find that sometimes my assets don't update in the app when I add them to my projects.
There are two ways you can fix this problem:
Clean and rebuild the project.
Uninstall the app on your phone and install it from scratch using ADT.
Simple as that!

Just to add confirmation to CommonsWare's answer, I just came across this exact bug for a project targeting 2.3.3+. I had to Delete the following:
<data android:scheme="com.android.ApplicationName"></data>
Then I had to Clean the project. I think that having to use adb to install every time is a sign of something wrong with the Manifest, and will come back to bite you later (once in the Market specificially).