使用android-support-v7：21库在工具栏上不显示ActionBarDrawerToggle

Question

尝试从android-support-v7：21库实现新的抽屉切换，但未显示。 代码段：

public class MainActivity extends ActionBarActivity {

    private Toolbar mToolbar;
    private DrawerLayout mDrawerLayout;
    private ActionBarDrawerToggle mDrawerToggle;

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

        initToolbar();
    }

    private void initToolbar() {
        mToolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(mToolbar);

        mDrawerLayout = (DrawerLayout) findViewById(R.id.drawerLayout);
        mDrawerToggle = new ActionBarDrawerToggle(
                this,
                mDrawerLayout,
                mToolbar,
                R.string.drawer_open,
                R.string.drawer_close
        );
        mDrawerLayout.setDrawerListener(mDrawerToggle);
    }
}

Answer 1

您应该在活动的syncState方法中mDrawerToggle上调用onPostCreate方法：

    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);

        mDrawerToggle.syncState();
    }