Android双击back按钮退出实现

重写OnBackPressed()方法，activity布局为DrawerLayout

@Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
if((System.currentTimeMillis()-mBackPressed)>TIME_INTERVAL){
mBackPressed=System.currentTimeMillis();
Utils.showShortToast(getApplicationContext(),"再按一次退出");
}else{
//如果连续两次back按钮单击事件时间小于2s
Utils.finish(this);
}
}
}