drawerLayout 监听事件

若是哦咱们须要侧滑屏幕来弹出一个侧边栏，咱们能够经过drawerLayout来实现。它有监听事件，里面有四个方法。咱们先看以下的代码，咱们在代码中打一些log来看看这四个方法的执行状况
mDrawerLayout.setDrawerListener(new DrawerListener() {
            @Override
            public void onDrawerStateChanged(int arg0) {

                android.util.Log.e("zhangshuli", "statechange");
            }   

            @Override
            public void onDrawerSlide(View arg0, float arg1) {

                android.util.Log.e("zhangshuli", "slide");

            }   

            @Override
            public void onDrawerOpened(View arg0) {

                android.util.Log.e("zhangshuli", "open");
            }   

            @Override
            public void onDrawerClosed(View arg0) {

                android.util.Log.e("zhangshuli", "colse");
            }
        });
但咱们把drawerLaout从隐藏到滑出时候，log打印结果以下
03-21 11:58:57.163 E/zhangshuli(28603): statechange
03-21 11:58:57.171 E/zhangshuli(28603): slide
03-21 11:58:57.204 E/zhangshuli(28603): slide
03-21 11:58:57.238 E/zhangshuli(28603): slide
03-21 11:58:57.262 E/zhangshuli(28603): slide
03-21 11:58:57.290 E/zhangshuli(28603): slide
03-21 11:58:57.317 E/zhangshuli(28603): slide
...............
03-21 11:58:57.590 E/zhangshuli(28603): open
03-21 11:58:57.591 E/zhangshuli(28603): statechange

当咱们从滑出状态到隐藏的时候，log以下
03-21 12:05:27.180 E/zhangshuli(28603): statechange
03-21 12:05:27.190 E/zhangshuli(28603): slide
03-21 12:05:27.215 E/zhangshuli(28603): slide
03-21 12:05:27.246 E/zhangshuli(28603): slide
03-21 12:05:27.270 E/zhangshuli(28603): slide
03-21 12:05:27.295 E/zhangshuli(28603): slide
.................
03-21 12:05:27.485 E/zhangshuli(28603): slide
03-21 12:05:27.506 E/zhangshuli(28603): slide
03-21 12:05:27.527 E/zhangshuli(28603): slide
03-21 12:05:27.561 E/zhangshuli(28603): slide
03-21 12:05:27.601 E/zhangshuli(28603): colse
03-21 12:05:27.601 E/zhangshuli(28603): statechange

咱们能够得出结论
1.onDrawerStateChanged：老是在drawerlayout状态发生切换时候执行两次，一次是状态刚刚发生改变的时候，一次是状态改变完全完成的时候，它老是在监听事件最开始跟末尾个执行一次
2.onDrawerSlide：它是在状态发生改变的过程当中一直执行
3.onDrawerOpened（打开）、onDrawerClosed（关闭）：他们是在状态改变完成之后执行，是发生在第二次onDrawerStateChanged前面