如何仅在主要活动中显示菜单？

Question

I want to only show my menu in my main activity then have a back button from my other activities instead of a menu. Right now I am just wondering how would I would remove the menu from the action bar on the activities I don't want it on.

My Manifest:

<?xml version="1.0" encoding="utf-8"?>

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:name=".Insulter"
        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="Favourites"
        android:launchMode = "singleInstance">
    </activity>

    <activity
        android:name="Settings"
        android:launchMode = "singleInstance">
    </activity>


</application>

My menu opener inside my main activity:

@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();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        Intent startSettings = (new Intent(Insulter.this,Settings.class));
        startActivity(startSettings);
        return true;
    } else if (id == R.id.exit_the_app) {
        finish();
        return true;
    } else if (id == R.id.favourites) {
        Intent startFavs = (new Intent(Insulter.this, Favourites.class));
        String[] objects = new String[favs.size()];
        favs.toArray(objects);
        final ArrayList<String> list = new ArrayList<>(Arrays.asList(objects));
        startFavs.putStringArrayListExtra("favs",list);
        startActivity(startFavs);
        return true;
    }


    return super.onOptionsItemSelected(item);
}

Answer 1

Activity.onCreateOptionsMenu is the place where it gets created. Just don't override this method or let it return false to not show the menu.

You must return true for the menu to be displayed; if you return false it will not be shown.

If you're using the same implementation for all your activities, define a field boolean isMain and return it from onCreateOptionsMenu

public boolean onCreateOptionsMenu (Menu menu) {
    if (!isMain)
        return false;

    [creating the menu here like before]
}

Answer 2

如果您想在任何活动中使用菜单，则需要覆盖onCreateOptionsMenu和onOptionsItemSelected ...。如果您不想使用菜单，则只需在活动中不覆盖这些方法...

Answer 3

For each activity that you create, there must be a menu file associated with it in the res/menu folder. Simply delete or comment the corresponding <item> tags. You may experiment with them by looking at the output show in the preview screen.

Note: I think this works only when an activity is created automatically using the UI (ie not manually) since the corresponding menu file is generated automatically with it.

Answer 4

You need to use following steps to remove options menu and add back button in your non-main activities --

1. Don't override onCreateOptionsMenu method.
2. call getActionBar().setDisplayHomeAsUpEnabled(true) in your activity's onCreate method.

3. Override onOptionsItemSelected method in following way--

    @Override public boolean onOptionsItemSelected(MenuItem item) { switch(item.getItemId()) { case android.R.id.home: finish(); return super.onOptionsItemSelected(item); } }