注销无法与导航抽屉一起使用

Question

logout with navigation drawer. i have some trouble in my code. logout is working, but before go to the loginactivity , i get unfortunately stopped hope someone can solve my problem. thx

logcat showed error on line 128 & 175 i have command in line 128 & 175

public class MainActivity extends Activity {

private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
private ActionBarDrawerToggle mDrawerToggle;

private CharSequence mDrawerTitle;
private CharSequence mTitle;
CustomDrawerAdapter adapter;
SharedPreferences preferences;
String pref;
List<DrawerItem> dataList;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    preferences = this.getSharedPreferences(Config.PREFERENCES, MODE_PRIVATE);
    pref = preferences.getString(Config.SESSION,null);
    // Initializing
    dataList = new ArrayList<DrawerItem>();
    mTitle = mDrawerTitle = getTitle();
    mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
    mDrawerList = (ListView) findViewById(R.id.left_drawer);

    mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow,
            GravityCompat.START);

    // Add Drawer Item to dataList
    dataList.add(new DrawerItem("Scanner", R.drawable.ic_action_email));
    dataList.add(new DrawerItem("Schedule", R.drawable.ic_action_good));
    dataList.add(new DrawerItem("Games", R.drawable.ic_action_gamepad));
    dataList.add(new DrawerItem("Logout", R.drawable.ic_action_about));


    adapter = new CustomDrawerAdapter(this, R.layout.custom_drawer_item,
            dataList);

    mDrawerList.setAdapter(adapter);

    mDrawerList.setOnItemClickListener(new DrawerItemClickListener());

    getActionBar().setDisplayHomeAsUpEnabled(true);
    getActionBar().setHomeButtonEnabled(true);

    mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,
            R.drawable.ic_drawer, R.string.drawer_open,
            R.string.drawer_close) {
        public void onDrawerClosed(View view) {
            getActionBar().setTitle(mTitle);
            invalidateOptionsMenu(); // creates call to
            // onPrepareOptionsMenu()
        }

        public void onDrawerOpened(View drawerView) {
            getActionBar().setTitle(mDrawerTitle);
            invalidateOptionsMenu(); // creates call to
            // onPrepareOptionsMenu()
        }
    };

    mDrawerLayout.setDrawerListener(mDrawerToggle);

    if (savedInstanceState == null) {
        SelectItem(0);
    }

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

public void SelectItem(int possition) {

    Fragment fragment = null;
    Bundle args = new Bundle();
    switch (possition) {
        case 0:
            fragment = new FragmentScan();
            break;
        case 1:
            fragment = new FragmentSchedule();

            break;
        case 2:
            fragment = new FragmentThree();
            args.putString(FragmentThree.ITEM_NAME, dataList.get(possition)
                    .getItemName());
            args.putInt(FragmentThree.IMAGE_RESOURCE_ID, dataList.get(possition)
                    .getImgResID());
            break;
        case 3:
            logout();
            Intent in = new Intent(this, LoginActivity.class);
            startActivity(in);
            finish();
            break;

        default:
            break;
    }

    fragment.setArguments(args);      //THIS IS LINE 128 (ERROR LOGCAT)
    FragmentManager frgManager = getFragmentManager();
    frgManager.beginTransaction().replace(R.id.content_frame, fragment)
            .commit();

    mDrawerList.setItemChecked(possition, true);
    setTitle(dataList.get(possition).getItemName());
    mDrawerLayout.closeDrawer(mDrawerList);

}

@Override
public void setTitle(CharSequence title) {
    mTitle = title;
    getActionBar().setTitle(mTitle);
}

@Override
protected void onPostCreate(Bundle savedInstanceState) {
    super.onPostCreate(savedInstanceState);
    // Sync the toggle state after onRestoreInstanceState has occurred.
    mDrawerToggle.syncState();
}

@Override
public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);
    // Pass any configuration change to the drawer toggles
    mDrawerToggle.onConfigurationChanged(newConfig);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // The action bar home/up action should open or close the drawer.
    // ActionBarDrawerToggle will take care of this.
    if (mDrawerToggle.onOptionsItemSelected(item)) {
        return true;
    }

    return false;
}

private class DrawerItemClickListener implements
        ListView.OnItemClickListener {
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position,
                            long id) {
        SelectItem(position);    //THIS IS LINE 175 (ERROR LOGCAT)

    }
}
//In the same activity you’ll need the following to retrieve the results:
private void logout(){
    //TODO delete cookie from db

    SharedPreferences.Editor editor = preferences.edit();
    editor.remove(Config.SESSION);
    editor.remove(Config.USERNAME);
    editor.commit();
}

}

logout is working now but before go to the loginactivity i get unfortunately stopped

and this my logcat

10-16 22:44:50.062    2202-2202/com.example.blackcustomzier.skripsi E/AndroidRuntime﹕ FATAL EXCEPTION: main
    java.lang.NullPointerException
            at com.example.blackcustomzier.skripsi.MainActivity.SelectItem(MainActivity.java:128)
            at com.example.blackcustomzier.skripsi.MainActivity$DrawerItemClickListener.onItemClick(MainActivity.java:175)
            at android.widget.AdapterView.performItemClick(AdapterView.java:298)
            at android.widget.AbsListView.performItemClick(AbsListView.java:1100)
            at android.widget.AbsListView$PerformClick.run(AbsListView.java:2788)
            at android.widget.AbsListView$1.run(AbsListView.java:3463)
            at android.os.Handler.handleCallback(Handler.java:730)
            at android.os.Handler.dispatchMessage(Handler.java:92)
            at android.os.Looper.loop(Looper.java:137)
            at android.app.ActivityThread.main(ActivityThread.java:5103)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:525)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
            at dalvik.system.NativeStart.main(Native Method)

Answer 1

It looks like you have a copy/paste error. You only have 5 fragments, but you have 6 cases in your switch with cases 3 and 4 containing the same code. Case 4 should be your logout logic.