Question

我在android studio中关注Slidnerd的材质设计教程，我被困在导航抽屉里。

这是我的NavigationDrawerFragment.java

            package com.example.baumann.perfectposture;


            import android.content.Context;
            import android.content.SharedPreferences;
            import android.os.Bundle;
            import android.support.v4.app.Fragment;
            import android.support.v4.widget.DrawerLayout;
            import android.support.v7.app.ActionBarDrawerToggle;
            import android.support.v7.widget.Toolbar;
            import android.view.LayoutInflater;
            import android.view.View;
            import android.view.ViewGroup;
            import android.content.ComponentName;
            import android.content.Intent;
            import android.graphics.drawable.Drawable;
            import android.os.Bundle;
            import android.os.Handler;
            import android.support.v4.app.Fragment;
            import android.support.v4.app.FragmentManager;
            import android.support.v4.app.FragmentStatePagerAdapter;
            import android.support.v4.view.ViewPager;
            import android.support.v4.widget.DrawerLayout;
            import android.support.v7.app.ActionBarActivity;
            import android.support.v7.widget.Toolbar;
            import android.view.Menu;
            import android.view.MenuItem;
            import android.view.View;
            import android.view.ViewGroup;
            import android.widget.ImageView;


            /**
             * A simple {@link Fragment} subclass.
             */
            public class NavigationDrawerFragment extends Fragment {

                public static final String PREF_FILE_NAME="testpref";
                public static final String KEY_USER_LEARNED_DRAWER="user_learned_drawer";
                private ActionBarDrawerToggle mDrawerToggle;

                private boolean mUserLearnedDrawer;
                private boolean mFromSavedInstanceState;

                public NavigationDrawerFragment() {
                    // Required empty public constructor
                }

                @Override
                public void onCreate(Bundle savedInstanceState) {
                    super.onCreate(savedInstanceState);
                    mUserLearnedDrawer=Boolean.valueOf(readFromPreferences(getActivity().KEY_USER_LEARNED_DRAWER,"false"));   
                    if(savedInstanceState==null){
                        mFromSavedInstanceState=true;
                    }
                }

                @Override
                public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                         Bundle savedInstanceState) {
                    // Inflate the layout for this fragment
                    return inflater.inflate(R.layout.fragment_navigation_drawer, container, false);
                }


                public void setUp(DrawerLayout drawerLayout, Toolbar toolbar) {
                    mDrawerLayout = drawerLayout;
                    mDrawerToggle = new ActionBarDrawerToggle(getActivity(), drawerLayout, toolbar, R.string.drawer_open, R.string.drawer_closed) {
                        @Override
                        public void onDrawerOpened(View drawerView) {
                            super.onDrawerOpened(drawerView);
                        }

                        @Override
                        public void onDrawerClosed(View drawerView) {
                            super.onDrawerClosed(drawerView);
                        }
                    };
                    mDrawerLayout.setDrawerListener(mDrawerToggle);

                }
                    public static void saveToPreferences(Context context, String preferenceName, String preferenceValue){
                        SharedPreferences sharedPreferences=context.getSharedPreferences(PREF_FILE_NAME, Context.MODE_PRIVATE);
                        SharedPreferences.Editor editor=sharedPreferences.edit();
                        editor.putString(preferenceName, preferenceValue);
                        editor.apply();
                    }
                    public static String readFromPreferences(Context context, String preferenceName, String defaultValue) {
                        SharedPreferences sharedPreferences = context.getSharedPreferences(PREF_FILE_NAME, Context.MODE_PRIVATE);
                        return sharedPreferences.getString(preferenceName,defaultValue);
                    }

            }

以下是强调的内容：

"KEY_USER_LEARNED_DRAWER" in：

mUserLearnedDrawer=Boolean.valueOf(readFromPreferences(getActivity().KEY_USER_LEARNED_DRAWER,"false"));

和

"mDrawerLayout"两次：

mDrawerLayout = drawerLayout;

和

mDrawerLayout.setDrawerListener(mDrawerToggle);

以下是我的三个错误：

Error:(52, 77) error: cannot find symbol variable KEY_USER_LEARNED_DRAWER Error:(67, 9) error: cannot find symbol variable mDrawerLayout Error:(79, 9) error: cannot find symbol variable mDrawerLayout

Answer 1

更改“。”在getActivity()进入“，”之后 mUserLearnedDrawer=Boolean.valueOf(readFromPreferences(getActivity(),KEY_USER_LEARNED_DRAWER,"false"));
声明一个字段private DrawerLayout mDrawerLayout;，您可以将抽屉分配给。{/ p>

Android Studio导航抽屉找不到符号变量mDrawerLayout或KEY_USER_LEARNED_DRAWER

1 个答案: