使用 android-support-v7:21 库的工具栏上未显示 ActionBarDrawerToggle

Question

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

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

你应该叫syncState上方法mDrawerToggle在活动的onPostCreate方法：

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

        mDrawerToggle.syncState();
    }