侧拉箭头动画

private void initView() {
         ActionBar ab=getSupportActionBar();
         ab.setDisplayHomeAsUpEnabled(true);
         DrawerLayout drawer=(DrawerLayout) findViewById(R.id.drawer);
         //把ActionBar和DrawerLayout绑定
         abt = new ActionBarDrawerToggle(this, drawer, R.string.drawer_open, R.string.drawer_close);
        //改变图标
         abt.syncState();
         //显示动画
         drawer.setDrawerListener(abt);
        
    }