活动中缺少导航抽屉汉堡包图标

Question

I built a Navigation Drawer with fragments and an Activity. All the fragments have the icon and drawer access is smooth as butter, but there is nothing in the Activity. The Activity is the default "Home Page", so access to the Navigation Drawer is critical. Typically not calling toggle.syncState(); is the solution, but it fails in this case.

MainActivity:

public class MainActivity extends AppCompatActivity
    implements NavigationView.OnNavigationItemSelectedListener {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    Toolbar toolbar = findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    DrawerLayout drawer = findViewById(R.id.drawer_layout);
    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
            this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
    drawer.addDrawerListener(toggle);
    toggle.setDrawerIndicatorEnabled(true);
    toggle.syncState();

    NavigationView navigationView = findViewById(R.id.nav_view);
    navigationView.setNavigationItemSelectedListener(this);

    //Sets default fragment
    Intent i = new Intent(MainActivity.this,GarageActivity.class);
    startActivity(i);

    navigationView.setCheckedItem(R.id.nav_garage);
}

//Name in Action bar
public void setActionBarTitle(String title) {
    getSupportActionBar().setTitle(title);
}

@Override
public void onBackPressed() {
    DrawerLayout drawer = findViewById(R.id.drawer_layout);
    if (drawer.isDrawerOpen(GravityCompat.START)) {
        drawer.closeDrawer(GravityCompat.START);
    } else {
        super.onBackPressed();
    }
}

Activity in question:

public class GarageActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_garage);
    getSupportActionBar().setTitle("My Garage");
}

}

Manifest:

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

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity
        android:name=".MainActivity"
        android:label="@string/app_name"
        android:theme="@style/AppTheme.NoActionBar">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity android:name=".GarageActivity">
        <meta-data
            android:name="android.support.parent_activity"
            android:value=".MainActivity"/>
    </activity>
</application>

Answer 1

First you need to enable actionbar's Home button. Then Assign Hamburger icon to Home button and write code to open the drawer in his listener. following are the steps:

1. Get hamburger/menu icon:

   In the Project window, right-click the res folder and select New > Vector Asset.

   Select Material icon as the asset type and then click the Icon button to open the Select Icon window.

   Search for " menu " and select the menu icon (the icon is 3 horizontal lines). Click OK, and then rename the file to "ic_menu" and click Next to import it.

2. Enable "Home" button in actionbar:

   add this code in your onCreate method:-

    ActionBar actionbar = getSupportActionBar(); actionbar.setDisplayHomeAsUpEnabled(true); actionbar.setHomeAsUpIndicator(R.drawable.ic_menu); 

3. Add code in onOptionsItemSelected method:

   first create global variable of DrawerLayout so you can access it in other methods. add reference to that variable in onCreate and use it in onOptionsItemSelected to open the drawer. following is the code:

    public class MainActivity extends AppCompatActivity { private DrawerLayout mDrawerLayout; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mDrawerLayout = findViewById(R.id.drawer_layout); ... } @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case android.R.id.home: mDrawerLayout.openDrawer(GravityCompat.START); return true; } return super.onOptionsItemSelected(item); } } 

source Create Navigation Drawer