java - onBackPressed 添加带有抽屉导航的双击退出？

Question

我想按照下面的方式进行编码..

boolean doubleBackToExitPressedOnce = false;
@Override
public void onBackPressed() {
    if (getFragmentManager().getBackStackEntryCount() > 0) {
        getFragmentManager().popBackStack();
    } else {
        Fragment fragment = getFragmentManager().findFragmentById(R.id.container);
        if (fragment instanceof MainHomeFragment) {
            if (doubleBackToExitPressedOnce) {
                super.onBackPressed();
                return;
            }

            this.doubleBackToExitPressedOnce = true;
            Toast.makeText(this, "Please click BACK again to exit", Toast.LENGTH_SHORT).show();

            new Handler().postDelayed(new Runnable() {

                @Override
                public void run() {
                    doubleBackToExitPressedOnce = false;
                }
            }, 2000);
        }
        else {
            super.onBackPressed();
        }
    }
}

我的问题是当抽屉打开时，onbackpressed 无法关闭抽屉..我想在下面添加代码......我应该把代码放在哪里？

DrawerLayout mDrawerLayout = (DrawerLayout) findViewById(R.id.drawerLayout);
    if (mDrawerLayout.isDrawerOpen(GravityCompat.START)) {
       mDrawerLayout.closeDrawer(GravityCompat.START);
    }

Answer 1

 @Override
                public void onBackPressed() {DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
                if (drawer.isDrawerOpen(GravityCompat.START)) {
                    drawer.closeDrawer(GravityCompat.START);
                } else {
                   doExitApp()
    }

在 Activity 中覆盖你的 on backpressed 方法

public void doExitApp(){
                if ((System.currentTimeMillis() - exitTime) > 2000) {
                    Toast.makeText(this, R.string.press_again_exit_app, Toast.LENGTH_SHORT).show();
                    exitTime = System.currentTimeMillis();
                } else {
                    finish();
                }
            }