I am a noob in android development and I follow the tutoral of the android website.
1. In the part of "Starting Another Activity", I just copied the code and tried to run it, but I found after the activity is changed (changed to new page), the title of action bar will change to the name of the class of that activity.
2. When it talks about the respond of the action button, the code is written as:
public boolean onOptionsItemSelected(MenuItem item) {
// Handle presses on the action bar items
switch (item.getItemId()) {
case R.id.action_search:
openSearch();
return true;
case R.id.action_settings:
openSettings();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
However, in the default code:
`public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}`
It only return true which contains no method to respond(no openSettings()), but a "setting" word still pop out when I press it.
3. How do I remove the action bar and make it full screen?
Don't fully understand your question (you really didn't ask one specifically) but I think this is what you're asking
How to change the title of a new activity?
Here: How do I change the android actionbar title and icon
How does settings open up?
Android does this automatically, if the onCreateOptionsMenu(Menu menu) is called.
How do i make a full screen activity?
Here: Fullscreen Activity in Android?
In the future, be sure to look through Google and StackOverflow for you answers, most likely someone has already asked a similar question
The Name of the activity is, in your case, is declared in AndroidManifest.xml. Check the android:label attribute of your activity. You can manipulate it through java code if you want. See this SO question.
Check the menu file under res/menu/your_menu_file.xml. I think it contains something like
<item
android:id="#+id/action_settings"
android:orderInCategory="100"
android:showAsAction="never"
android:title="#string/action_settings"/>
The displayed icon is NOT setting icon, but overflow icon. If the overflow icon is clicked, it lists all menu items. In your case only one (i.e Setting)
To hide the action bar, include these in your onCreate() method
//getWindow().requestWindowFeature(Window.FEATURE_NO_TITLE);
getActionBar().hide();
You can also do it via xml. Look at this SO question.
Related
I'm making an Android app that allows the user to search a collection of information. I begin by displaying the collection, but when a search button in the actionbar is tapped, an action layout (search bar) shows in the action bar. When a search is conducted, the listview information is replaced with information from the query. However, when a user taps the back arrow button next to the search bar, I would like to replace the queried information with the original information.
Is there any way to detect when the back arrow button is tapped next to the search bar? Thank you very much for your help!
Menu XML
<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
tools:context="">
<item
android:id="#+id/search"
android:title="Search"
android:showAsAction="always|collapseActionView"
android:actionLayout="#layout/some_layout"
/>
</menu>
Activity Code: trying this: SearchView onMenuItemActionCollapse Not Working
but keep getting a Null Pointer Exception
There are some ways to detect it indeed. First thing that came up to me was the following: create a boolean with false as default value. Whenever you query for specific search results, you turn the boolean to the true. When the 'back arrow' (navigation up) button has been pressed, you check whether the boolean turns out to be true. If it's true, it means that the app doesn't show you the original information set and shouldn't close your activity.
For example (from Google docs, partly.):
public boolean originalContentReplaced = false;
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
// Respond to the action bar's Up/Home button
case android.R.id.home:
if(originalContentReplaced) {
// Do what you need to do here to get the original content back.
this.originalContentReplaced = false;
} else {
NavUtils.navigateUpFromSameTask(this);
// You could also use onBackPressed().
}
return true;
}
return super.onOptionsItemSelected(item);
}
I don't know how you query your new search results but when your search is successful, you should change originalContentReplaced variable to true.
You could use the very same if-else statement when you press on the hardware back button. Anyway, this should give you a very clear idea on how to detect when the navigation up/back arrow button is pressed. :)
I'm practising adding menu items and trying to react to menu item clicks. According to the developer's guide, it says:
Tip: Android 3.0 adds the ability for you to define the on-click behavior for a menu item in XML, using the android:onClick attribute. The value for the attribute must be the name of a method defined by the activity using the menu. The method must be public and accept a single MenuItem parameter—when the system calls this method, it passes the menu item selected. For more information and an example, see the Menu Resource document.
However, the sample code in the same page doesn't follow the rule: the methods do not pass the MenuItem parameter. The sample code is:
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle item selection
switch (item.getItemId()) {
case R.id.new_game:
newGame();
return true;
case R.id.help:
showHelp();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
My question is: Shouldn't method calls be newGame(MenuItem item) and showHelp(MenuItem item), instead of newGame() and showHelp()? When I tested my own, (MenuItem item) argument was needed in fact, otherwise, the app was crashing, even though it compiles correctly.
Any help would be appreciated.
onOptionsItemSelected is the alternative to defining onClick attributes and what is available prior to Android 3.0 (important if you want to be backward compatible). It is simply a different way of providing the same process flow. Of course, onClick has the potential to crash your application on runtime, rather than onOptionsItemSelected not handling a menu item (simply causing it to do nothing).
I am developing an Android app and I am trying to put a menu item into the ActionBar.
It has enough space, so it shouldn't be on the overflow or anything.
In my menu.xml I have added that item + android:showAsAction="ifRoom|withText"
However, no matter how large the screen is, that damn menu will not show up on the ActionBar (although it is present in the menu, if the user presses a key).
Unfortunately I cannot post any full-code since I am under a non-disclosure agreement, but I will answer all questions.
The section where I inflate the menu:
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.drinks, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
NavUtils.navigateUpFromSameTask(this);
return true;
case R.id.done:
//stuff
}
return super.onOptionsItemSelected(item);
}
Since you have only a menu item, use this attribute instead: android:showAsAction="always".
EDIT Above works all the time if you're running the code on post Honeycomb. But, in order to run on pre-Honeycomb, according to developer article, you need to extend from ActionBarActivity, that means adding compatibility support v4 & v7 and set the following theme for your activity:
<activity android:theme="#style/Theme.AppCompat.Light" ... >
... or a Them.AppCompat theme. Or use one of your own that extends from these.
I'm having an issue connected with actions oferflow. On mdpi device with Android 2.3 on board, when I put two actions on the action bar and then add a ShareActionProvider it overflows to be under hardware menu button instead the overflow icon.
What is happening is partially acceptable, but the ShareActionProvider does not work at all under those circumstances. When I roll over the menu panel and click nothing happens.
Oh, I'm using AB Sherlock 4.2.0.
Do you know any workaround?
Thanks!
Current workround for me is to handle generic onOptionsItemSelected for provider's ID and do as follows:
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
[...]
case R.id.menu_item_share:
startActivity(Intent.createChooser(mShareIntent, getString(R.string.share_title)));
return true;
default:
return super.onOptionsItemSelected(item);
}
}
But it'd be nice to see this fixed. :)
I have been used this example, in this example you have to add /libs/android-support-v4.jar library file and and put a break point on public boolean onMenuItemSelected(int featureId, MenuItem item) method in /src/android/support/v4/app/Watson.java
line no. 115
debug source code when you use app for lower version api where "Menu" button exist.
Hope you will be able to find problem.
This topic can look similar to others but I haven't found any usable answer for this case.
Here is what I want : I have a TabActivity with a menu, containing tabs without any menu. When I press the menu button, I want the only existing menu to be displayed. If I only inflate the menu, this is working fine. But if I want to change the content of the menu (change the visibility of items in the onPrepareOptionsMenu(menu) method) or even press the items of the menu, nothing works.
For the onPrepareOptionsMenu(menu), the problem seems to be coming from the menu.findItem(...) method which returns a null Object, and I have a NullPointerException !
In onOptionsItemSelected(item), none of the item IDs will be recognized.
I have noticed with the debugger that the menu Context is the activity of the current tab, so I have moved the menu inside of that activity instead, but without more success.
Last thing, I was using the same menu and very similar code in a previous version of the app, using a single activity (no tabs) and I didn't encounter any problem. When I moved to the TabActivity design it was first working fine (maybe the context of the menu was my TabActivity instead of the Activity of the tab), but it didn't work anymore after minor changes to the Activities of the tabs (nothing related to any menu).
If you think using ActionBar (and the support package) would fix this, I am already planning in moving to it later, but I would like to understand and fix this first.
Here is the code :
#Override
public boolean onCreateOptionsMenu(Menu menu)
{
getMenuInflater().inflate(R.menu.main_menu, menu);
return true;
}
#Override
public boolean onPrepareOptionsMenu(Menu menu)
{
MenuItem connect1 = menu.findItem(R.id.connect_1);
MenuItem connect2 = menu.findItem(R.id.connect_2);
// Here I do some stuff to prepare the menu, which could be simplified
// like this :
if (device1Connected)
if (!connect1.isVisible()) // here I get the NullPointerException
connect1.setVisible(true);
return super.onPrepareOptionsMenu(menu);
}
#Override
public boolean onOptionsItemSelected(MenuItem item)
{
// Handle item selection
switch (item.getItemId()) {
case R.id.select_device:
// do some stuff
return true;
case R.id.connect_1:
// do some stuff
return true;
case R.id.connect_2:
// do some stuff
return true;
case R.id.disconnect:
// do some stuff
return true;
default:
return super.onOptionsItemSelected(item);
}
}
Here is the XML file of the menu, nothing special
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
<item android:id="#+id/select_device"
android:icon="#drawable/icon"
android:title="#string/choose_devices"/>
<item android:id="#+id/connect_1"
android:icon="#android:drawable/ic_menu_add"
android:title="#string/connect_1" />
<item android:id="#+id/connect_2"
android:icon="#android:drawable/ic_menu_add"
android:title="#string/connect_2" />
<item android:id="#+id/disconnect"
android:icon="#android:drawable/ic_menu_close_clear_cancel"
android:title="#string/disconnect" />
</menu>
Edit : I have added the following in the onPrepareOptionsMenu(menu) to avoid the NullPointerException. It doesn't fix the real problem but I can now see precisely what happens when I click on a MenuItem
if (connect1 == null || connect2 == null)
return super.onPrepareOptionsMenu(menu);
When I click on the first item, getItemId() returns, for example, 2131165207, and the second item returns 2131165208 (I have checked, they are ids of Views of the second tab !!), but the values it should return to enter the switch/case are respectively 2131165215 and 2131165216, so as I said before, I have a problem with my item ids. I made this test with the menu within the Activity of the first tab, because the mContext value of the menu is always an instance of the current Activity. But even though the Context AND the Activity containing the menu are the same, it still doesn't work.
So ! I have finally figured out what was wrong. It was a building/compiling error. I have been trying before refreshing the project many time, but it was not enough, I had also tried deleting the R.java file (where are compiling the ID numbers from the XML files), but it still didn't work; and I finally remembered about the Project -> Clear... function in Eclipse while working on another project.
And it just worked. So that was nothing there very challenging, but at least I've learnt something valuable today.