Question

我制作了一个使用导航抽屉的简单应用程序，我不喜欢后退按钮的工作方式。如果我从抽屉打开一个片段，然后按下后退按钮就会关闭应用程序。我想按下后退按钮（无论我在哪个片段中）来显示导航面板（就像在Zedge应用程序中一样）。

MainActivity：

private void displayView(int position) {
        // update the main content by replacing fragments
        Fragment fragment = null;

        switch (position) {
            case 0:
                fragment = new HomeFragment();
                break;
            case 1:
                fragment = new Audi();
                break;
            case 2:
                fragment = new BMW();
                break;
            case 3:
                fragment = new Volkswagen();
                break;
            case 4:
                fragment = new Kia();
                break;
            case 5:
                fragment = new Volvo();
                break;

            default:
                break;
        }

        if (fragment != null) {
            FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
            ft.replace(R.id.frame_container, fragment).commit();

            mDrawerList.setItemChecked(position, true);
            mDrawerList.setSelection(position);
            setTitle(navMenuTitles[position]);
            mDrawerLayout.closeDrawer(mDrawerList);

        } else {
            // error in creating fragment
            Log.e("MainActivity", "Error in creating fragment");
        }
    }

   @Override
    public void onBackPressed() {
        if (mDrawerLayout.isDrawerOpen(Gravity.START)) {
            mDrawerLayout.closeDrawer(Gravity.START);
        } else {
            super.onBackPressed();
        }
    }

Answer 1

在提交之前需要将片段添加到backstack，在.commit（）之前添加此代码并再试一次;

.addToBackStack()

onBackPressed显示导航抽屉面板

1 个答案: