I need to enable a MenuItem when a previous screen (Activity) returns.
I tried this code:
...
((MenuItem)findViewById(R.id.menu_how)).setEnabled(true);
...
but a null pointer exception is launched.
BTW, the menu_how is set to false in xml; and the code is part of onActivityResult(int requestCode, int resultCode, Intent data) call.
Try using menu.findItem(R.id.menu_how) in onCreateOptionsMenu and save a reference for later use.
This should work fine with enabled, however, I've found that setting a menu item to invisible in the XML means you can't show/hide it programmatically.
I found something at the android dev site that might be helpful (look for the section "Changing menu items at runtime")
It said that the onCreateOptionsMenu() method fired only when the the menu for the activity is created, and it happens when this activity starts. So if you want to change the menu items after the menu/activity was created, you need to override the onPrepareOptionsMenu() method instead. search the link for full details.
EDIT:
Just made it and it's working fine. I'm using one boolean var per menuItem which represents if this item should be enabled or not. This is my code:
/*************************************Game Menu**************************************/
#Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.game_menu, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle item selection
switch (item.getItemId())
{
case R.id.gm_new_game:
//newGame();
return true;
case R.id.gm_stand_up:
//some code when "gm_stand_up" button clicked..
return true;
case R.id.gm_forfeit:
//some code when "gm_forfeit" button clicked..
return true;
case R.id.gm_surrender:
//some code when "gm_surrender" button clicked..
return true;
case R.id.gm_exit_table:
exitTableCommand();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
#Override
public boolean onPrepareOptionsMenu(Menu menu)
{
menu.findItem(R.id.gm_forfeit).setEnabled(forfeitMenuButtonIsEnabled);
menu.findItem(R.id.gm_surrender).setEnabled(surrenderMenuButtonIsEnabled);
menu.findItem(R.id.gm_new_game).setEnabled(newGameMenuButtonIsEnabled);
menu.findItem(R.id.gm_stand_up).setEnabled(standUpMenuButtonIsEnabled);
return super.onPrepareOptionsMenu(menu);
}
where are you calling this? (Sorry, didn't read carefully) I think you need to call it after the menu is inflated (usually in OnCreateOptionsMenu). To do this, you can set a variable to true when the other Activity returns, then do ((MenuItem)findViewById(R.id.menu_how)).setEnabled(mMyBooleanField) in OnCreateOptionsMenu after the call to inflater.inflate.
Edit: To accomplish this in code, it might look something like this:
At the top of the class (along with all the other class members):
Boolean mEnableMenuItem = false;
In OnCreateOptionsMenu:
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.options_main, menu);
((MenuItem)findViewById(R.id.menu_how)).setEnabled(mEnableMenuItem );
In OnActivityResult:
mEnableMenuItem = true;
Keep a reference to Menu in your activity:
private Menu mMenu;
Then:
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_note, menu);
mMenu = menu;
return true;
}
Now, to access menu items anywhere in your activity use similar code to this:
mMenu.findItem(R.id.menu_how).setVisible(false);
or
mMenu.findItem(R.id.menu_how).setEnabled(true);
Related
i have three menu items "enable, diable, exit". what i want to do is, when the R.id.menu_enable_bt is chosen, i want to disable it using
menu.findItem(R.id.menu_enable_bt).setVisible(false);
but i can not call
menu.findItem(R.id.menu_enable_bt).setVisible(false);
from inside the onOptionsItemSelected(..) method.
how can i change the visibility of a menu item inside onOptionsItemSelected(..)
CODE:
#Override
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);
Log.w(TAG, SubTag.msg("onCreateOptionsMenu"));
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.menu, menu);
if (this.mBTAdapter.isEnabled()) {
menu.findItem(R.id.menu_enable_bt).setVisible(false);
menu.findItem(R.id.menu_disable_bt).setVisible(true);
} else {
menu.findItem(R.id.menu_enable_bt).setVisible(true);
menu.findItem(R.id.menu_disable_bt).setVisible(false);
}
return super.onCreateOptionsMenu(menu);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
super.onOptionsItemSelected(item);
Log.w(TAG, SubTag.msg("onOptionsItemSelected"));
switch (item.getItemId()) {
case R.id.menu_enable_bt:
Log.d(TAG, SubTag.bullet("onOptionsItemSelected", "menu_enable_bt"));
//menu.findItem(R.id.menu_enable_bt).setVisible(false); **how to do this**
this.mATEnableBT = new ATEnableBT();
this.mATEnableBT.execute();
break;
case R.id.menu_disable_bt:
Log.d(TAG, SubTag.bullet("onOptionsItemSelected", "menu_disable_bt"));
break;
case R.id.menu_exit:
Log.d(TAG,SubTag.bullet("onOptionsItemSelected", "menu_exit"));
finish();
break;
}
return super.onOptionsItemSelected(item);
}
you can use invalidateOptionsMenu() which will forse onCreateOptionsMenu to be called again.
From the documentation
Declare that the options menu has changed, so should be recreated. The
onCreateOptionsMenu(Menu) method will be called the next time it needs
to be displayed.
There you can check your conditions and undertake the needed actions
See the javadoc for onPrepareOptionsMenu. This is your opportunity to make changes to a menu just before it becomes visible to the user. So you should maintain some member variables describing what should be visible and use that to modify the menu items here.
I have a ListActivity (SherlockListActivity) and its content can be dynamically changed by the user. When the content changes, the options menu should be replaced.
As I learned, instead of onCreateOptionsMenu I should use onPrepareOptionsMenu that is (supposed to be) called every time the user selects the menu.
This is called right before the menu is shown, every time it is shown.
I have the following code:
#Override
public boolean onPrepareOptionsMenu(Menu menu)
{
menu.clear();
if (UserOption == UserOption1)
getSupportMenuInflater().inflate(R.menu.menu_option1, menu);
else
getSupportMenuInflater().inflate(R.menu.menu_option2, menu);
return super.onPrepareOptionsMenu(menu);
}
It is called only once during debug, so I always have the same menu.
What should I set to make it work?
Create and prepare the options menu for changing and its item selection method
#Override
public boolean onPrepareOptionsMenu(Menu menu) {
menu.clear();
MenuInflater inflater = getMenuInflater();
if(menuString=="red"){
inflater.inflate(R.menu.red_menu, menu);
}else if(menuString=="green"){
inflater.inflate(R.menu.green_menu, menu);
}
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle item selection
switch (item.getItemId()) {
case R.id.new_game:
return true;
case R.id.help:
return true;
default:
return super.onOptionsItemSelected(item);
}
}
Like whenever you want to change menu call
String menuString="red or green";
invalidateOptionsMenu();
Like others told, if you want to have static menu use onCreateOptionsMenu, and if you want to change its visibility dynamically use onPrepareOptionsMenu along with onCreateOptionsMenu
I'm tring to change a menuitem icon, but the icon is not being changed.
Here is how I find the MenuItem (works fine):
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu items for use in the action bar
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.activity_location_actions, menu);
mActionLocation = menu.findItem(R.id.action_location);
return super.onCreateOptionsMenu(menu);
}
Method UpdateIcon: I took a screenshot so you can see (in the red frame) that the images have been found by the system.
The mActionLocation is a MenuItem which is initialized before this Method is called and is not null.
Anyone has an idea?
UPDATE (solution by help from #vinitius)
The UpdateIcon method:
private void UpdateIcon(boolean locationOn) {
mActionLocation = locationOn; // mActionLocation is a global boolean
invalidateOptionsMenu();
}
The onPrepareOptionsMenu override:
#Override
public boolean onPrepareOptionsMenu(Menu menu) {
// Toggle location icon
if (mActionLocation) {
menu.findItem(R.id.action_location).setIcon(R.drawable.ic_location_on_white_24dp);
} else {
menu.findItem(R.id.action_location).setIcon(R.drawable.ic_location_off_white_24dp);
}
return super.onPrepareOptionsMenu(menu);
}
You need to use onPrepareOptionsMenu(Menu menu):
This is called right before the menu is shown, every time it is shown.You can use this method to efficiently enable/disable items or otherwise dynamically modify the contents.
Inside this method, retrieve your item as you do in onCreateOtionsMenu and check whether your gps in os or not to modify your item icon.
I'm using ActionBarSherlock in my project and sometimes need to add one or more items inside the action bar.
At this BaixadosFragment class (that extends SherlockFragment), I'm using the following code and it works fine:
#Override
public void onCreateOptionsMenu(Menu menu,MenuInflater inflater)
{
inflater.inflate(R.menu.main, menu);
super.onCreateOptionsMenu(menu, inflater);
}
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.refresh:
refresh();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
In this case, I'm adding a refresh button, witch is lonely inside main.xml
BUT I want to do the same at CupomDetalheActivity (though adding a share button), witch extends SherlockFragmentActivity instead. So I'm not able to override "onCreateOptionsMenu" as it has a different signature (below):
//this is inside SherlockFragmentActivity
public final boolean onCreateOptionsMenu(android.view.Menu menu) {
return true;
}
//this is inside SherlockFragment
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
//Nothing to see here.
}
Whith SherlockFragmentActivity, I don't even see where can I use the inflater to bring up the xml containing the share button...
I appreciate a lot any ideas and suggestions...
[EDIT] This worked, according to DroidT's suggestion:
#Override
public boolean onCreateOptionsMenu(Menu menu)
{
MenuInflater inflater = getSupportMenuInflater();
inflater.inflate(R.menu.share, menu);
super.onCreateOptionsMenu(menu);
return true;
}
Your SherlockFragmentActivity also has an onCreateOptionsMenu() and onPrepareOptionsMenu(). You can inflate your menu options in the onCreateOptionsMenu() by using getSupportMenuInflater(). You would want to make a call to invalidateOptionsMenu() in your SherlockFragmentActivity whenever you want the change to happen and add the menu options in onPrepareOptionsMenu(). For more information look at the "Changing menu items at runtime" section of this link.
If you are using a menu inside of a fragment, make sure you call setHasOptionsMenu(true); in the fragments onCreate(Bundle savedInstance) method
I have the below code and I can't understand why my code doesn't show up menu. If the activity containing data, condition_true = true otherwise condition_true = false. I can clearly see the control going to menutag and the condition is true too. Even I am getting Inflated string too in log. But still menu doesn't show up. I have seen lot of posts on these like link 1, link2 etc., but that didn't solve my problem. Can someone please help me on this issue?
#Override
public boolean onPrepareOptionsMenu(Menu menu) {
menu.clear(); //Clear view of previous menu
MenuInflater inflater = getSupportMenuInflater();
Log.d("menutag", condition_true);
if(condition_true)
{
inflater.inflate(R.layout.menu, menu);
Log.d("menutag","Inflated");
}
return super.onPrepareOptionsMenu(menu); // replaced this with true, but no use.
}
You have to add the options attributes in xml.. Otherwise you can do it programmatically like this:
public boolean onCreateOptionsMenu(Menu menu){
getMenuInflater().inflate(R.menu.yourmenuxmlfilename, menu);
return true;
}
public boolean onOptionsItemSelected(MenuItem item){
switch(item.getItemId){
case R.id.item1:
// what you want to do with first button
break;
case .....
break;
}
return true;
}
Maybe you're overriding onKeyDown and it always returns true? This can cause the problem, because it will catch the menu button pressed event too.