Android NavigationView头部设置监听事件

<android.support.design.widget.navigationview
    android:id="@+id/nav_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="start" />
  <!--删除下面两行-->
  <!--app:headerlayout="@layout/nav_header"-->
  <!--app:menu="@menu/nav_menu"-->

//findviewbyid
navigationview = (navigationview) findviewbyid(r.id.nav_view);

//引入header和menu
navigationview.inflateheaderview(r.layout.nav_header);
navigationview.inflatemenu(r.menu.nav_menu);

//获取头部布局
view navheaderview = navigationview.getheaderview(0);

private void initnavigation() {

    drawerlayout = (drawerlayout) findviewbyid(r.id.drawer_layout);
    navigationview = (navigationview) findviewbyid(r.id.nav_view);
    //引入header和menu
    navigationview.inflateheaderview(r.layout.nav_header);
    navigationview.inflatemenu(r.menu.nav_menu);
    //设置menu的监听事件
    navigationview.setnavigationitemselectedlistener(new navigationview.onnavigationitemselectedlistener() {
      @override
      public boolean onnavigationitemselected(@nonnull menuitem item) {
        switch (item.getitemid()) {
          case r.id.add_city:
            //启动
            startactivityforresult(new intent(mainactivity.this, citypickeractivity.class),
                request_code_pick_city);
            drawerlayout.closedrawers();
            break;
          case r.id.setting:
            intent settingintent = new intent(mainactivity.this, settingactivity.class);
            startactivity(settingintent);
            drawerlayout.closedrawers();
            break;
          case r.id.about:
            intent aboutintent = new intent(mainactivity.this, aboutactivity.class);
            startactivity(aboutintent);
            drawerlayout.closedrawers();
            break;
        }
        return false;
      }
    });

    //获取头部布局
    view navheaderview = navigationview.getheaderview(0);
    //设置监听事件
    icon_image = (circleimageview) navheaderview.findviewbyid(r.id.icon_image);
    icon_image.setonclicklistener(new view.onclicklistener() {
      @override
      public void onclick(view view) {
        dialog.show();
      }
    });

    //读取头像
    utility.getimagefromshare(this, icon_image);

    //dialog
    dialog = new customdialog(this, 100, 100, r.layout.dialog_photo, r.style.theme_dialog,
        gravity.bottom, r.style.pop_anim_style);
    //屏幕外点击无效
    dialog.setcancelable(false);

    btn_camera = (button) dialog.findviewbyid(r.id.btn_camera);
    btn_camera.setonclicklistener(new view.onclicklistener() {
      @override
      public void onclick(view view) {
        tocamera();
      }
    });

    btn_picture = (button) dialog.findviewbyid(r.id.btn_picture);
    btn_picture.setonclicklistener(new view.onclicklistener() {
      @override
      public void onclick(view view) {
        topicture();
      }
    });

    btn_cancel = (button) dialog.findviewbyid(r.id.btn_cancel);
    btn_cancel.setonclicklistener(new view.onclicklistener() {
      @override
      public void onclick(view view) {
        dialog.dismiss();
      }
    });

  }