How to programmatically trigger/click on a MenuIte

问题:

I have these menu items in my menu_main.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    tools:context=".MainActivity">

    <item android:id="@+id/action_restart" android:title="Restart"
        android:orderInCategory="1" />
    <item android:id="@+id/action_clear" android:title="Clear"
        android:orderInCategory="2" />
    <item android:id="@+id/action_update" android:title="Update"
        android:orderInCategory="3" />
    <item android:id="@+id/action_about" android:title="About"
        android:orderInCategory="4" />
    <item android:id="@+id/action_try_restart" android:title="Try Restart"
        android:orderInCategory="5" />
</menu>

And I have this in my onOptionsItemSelected method:

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    if (id == R.id.action_restart) {
        Toast.makeText(MainActivity.this, "Restart...", Toast.LENGTH_LONG).show();
    }

    if (id == R.id.action_clear) {
        Toast.makeText(MainActivity.this, "Clear...", Toast.LENGTH_LONG).show();
    }

    if (id == R.id.action_update) {
        Toast.makeText(MainActivity.this, "Update...", Toast.LENGTH_LONG).show();
    }

    if (id == R.id.action_about) {
        Toast.makeText(MainActivity.this, "About...", Toast.LENGTH_LONG).show();
    }

    if(id == R.id.action_try_restart) {
        // how to click / trigger the "action_restart" from here?
    }

    return super.onOptionsItemSelected(item);
}

I have tried with:

MenuItem actionRestart = (MenuItem) findViewById(R.id.action_restart);
actionRestart; //

But actionRestart reference doesn't offer anything like click, trigger, etc.

I'd also like to note that I'm new to Android development and I come from PHP/JavaScript background, so this level of Java OOP is all new to me.

回答1:

As far as I know, there is no mechanism in the SDK that lets you do this. It's certainly not standard practice to do this sort of thing.

I recommend decoupling your logic from the actual UI as much as possible, so you end up not needing to simulate a click to trigger the action. Since you're a Web developer, this should come fairly easily to you.

In this case, you'd want to refactor the toasts into a separate method (or multiple methods), and then call that both when the menu item is clicked and when you want to trigger it manually.

Alternatively, you could try taking the MenuItem returned by findViewById() and passing it to your handler there. But I have no idea if that'll work.

回答2:

You should manually call your listener, with required item as parameter.

MenuItem actionRestart = (MenuItem) findViewById(R.id.action_restart);
onOptionsItemSelected(actionRestart);

回答3:

Use the method performIdentifierAction, like this:

menu.performIdentifierAction(R.id.action_restart, 0);

回答4:

I would like to share my solution as well here. Instead of trying to click programmatically a menu item, I created a separate method for menu item click, and call it anywhere where I need to click menu item. OnOptionsItemSelected method looks as follows. As you can see I moved click logic to a separate method.

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    if (item.getItemId() == android.R.id.home) {
        homeClicked();
    }
    return super.onOptionsItemSelected(item);
}
private void homeClicked(){
    ...
}

Now you can call homeClicked anytime you need to click menu item programmatically.

回答5:

Even though it's not the best way to do,

MenuItem item_your_choice;

 @Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.your_menu, menu);
    item_your_choice = menu.findItem(R.id.item_your_choice);
    return super.onCreateOptionsMenu(menu);
}

 @Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
    case item_your_choice:
     //do whatever you want
     break;
 }

just Call from any method
  onOptionsItemSelected(item_you_choice);

回答6:

1. Make global Menu

   public Menu mMenu;
   

2. Assign menu to mMenu while override onCreateOptionMenu

   @Override
   public boolean onCreateOptionsMenu(Menu menu)
   {
       this.mMenu = menu;
       return super.onCreateOptionsMenu(menu);
   }
   

3. Call event like this:

   if(mMenu != null) {
       MenuItem action = mMenu.findItem(R.id.action_restart);
   
       if(action != null) {
           onOptionsItemSelected(action);
       }
   }
   

回答7:

As per your example for menu item above :

<item android:id="@+id/action_restart" android:title="Restart"
        android:orderInCategory="1" />

use callOnClick() method :

((ActionMenuItemView)findViewById(R.id.action_restart)).callOnClick();

回答8:

There is a standard method to do this -
Create a new instance of MenuItem class and change the overridden method getItemId() to return the id of desired menu item and leave the rest unchanged.

MenuItem actionRestart = new MenuItem() {
                                             @Override
                                             public int getItemId() {
                                               return R.id.action_restart;
                                             }

                                             ...

                                           };
onOptionsItemSelected(actionRestart);