Question

我正在使用ActionBarSherlock并创建了一个滑动选项卡显示。我试图通过使用对象引用创建视图，我已经尝试使用父活动的名称并使用它的强制转换。我在活动中有对象引用，这是我在结构中从较低级别的类中获得的。我希望能够在每个片段中使用这些引用，但我现在所说的对象是null。有人可以看看我的代码，看看我需要做些什么来解决这个问题。如果你不完全理解我想要解释的内容，请问我有关它的任何问题。提前谢谢。

这是我的父活动代码：

public class SlidingTabsActivity extends SherlockFragmentActivity
{
ViewPager viewPager;
TabsAdapter tabsAdapter;
ActionBar actionBarTabs;
Spinner spinner;
ImageButton newFile;
String[] languages = { "English", "Chinese", "German" };
ArrayAdapter<String> arrayAdapter;
LayoutInflater spinnerLayoutInflater;
View spinnerView;

PopupFirmware popupFirmware; // Popup firmware class instance
CommsLayerInterface commsLayerInterface;
DeviceLayerInterface deviceLayerInterface;

private DeviceInfo deviceInfo;
private Pages pages;
private Page page1;
private Page page2;
private Page page3;

@Override
protected void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);

    viewPager = new ViewPager(this);
    viewPager.setId(R.id.pager);
    setContentView(viewPager);

    arrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, languages);
    arrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spinnerLayoutInflater = (LayoutInflater) this.getBaseContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    spinnerView = spinnerLayoutInflater.inflate(R.layout.spinner, null);
    spinner = (Spinner) spinnerView.findViewById(R.id.tabsSpinner);
    spinner.setAdapter(arrayAdapter);
    spinner.setOnItemSelectedListener(new OnItemSelectedListener()
    {

        @Override
        public void onItemSelected(AdapterView<?> arg0, View arg1,
                int arg2, long arg3) 
        {
            // TODO Auto-generated method stub

        }

        @Override
        public void onNothingSelected(AdapterView<?> arg0) 
        {
            // TODO Auto-generated method stub

        }

    });
    newFile = (ImageButton) spinnerView.findViewById(R.id.tabsImageButton);
    newFile.setOnClickListener(new OnClickListener()
    {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub

        }

    });

    actionBarTabs = getSupportActionBar();
    actionBarTabs.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
    actionBarTabs.setCustomView(spinnerView);
    actionBarTabs.setDisplayShowCustomEnabled(true);
    actionBarTabs.setDisplayHomeAsUpEnabled(true);

    tabsAdapter = new TabsAdapter(this, viewPager); // Declares the tabs adapter class with the view pager view

    popupFirmware = new PopupFirmware(this); // Declaring popup firmware class

    commsLayerInterface = new CommsLayerInterface();
    deviceLayerInterface = new DeviceLayerInterface(this);
    deviceLayerInterface.setCommsLayerInterface(commsLayerInterface);
    deviceLayerInterface.updateValues();

    deviceInfo = deviceLayerInterface.getDeviceInfo();
    pages = deviceLayerInterface.getPages();
    setUpPages(pages);

    /* Adds fragments to the tabs adapter */
    tabsAdapter.addTab(actionBarTabs.newTab().setText("PV"), Fragment_1.class, null);
    tabsAdapter.addTab(actionBarTabs.newTab().setText("CONFIG"), Fragment_2.class, null);
    tabsAdapter.addTab(actionBarTabs.newTab().setText("DIAG"), Fragment_3.class, null);

}

public DeviceInfo getDeviceInfo()
{
    return deviceInfo;
}

public Pages getPages()
{
    return pages;
}

public Page getPage1()
{
    return page1;
}

public Page getPage2()
{
    return page2;
}

public Page getPage3()
{
    return page3;
}

@Override
public boolean onCreateOptionsMenu(com.actionbarsherlock.view.Menu menu) 
{   
    com.actionbarsherlock.view.MenuInflater inflater = getSupportMenuInflater();
    inflater.inflate(R.menu.tabs, menu);
    return super.onCreateOptionsMenu(menu);    
}

@Override
public boolean onOptionsItemSelected(com.actionbarsherlock.view.MenuItem item)
{
    switch (item.getItemId()) 
    {
        case android.R.id.home:
            /* Goes up a level in the application structure to the activity before this one */
            Intent upIntent = new Intent(this, MainActivity.class);
            upIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            startActivity(upIntent);
            return true;
        case R.id.action_home:
            /* Opens up the MainActivity activity */
            Intent homeIntent = new Intent(this, MainActivity.class);
            startActivity(homeIntent);
            return true;
        case R.id.refresh:
            /* Refreshes the current activity */
            Intent refreshIntent = getIntent();
            finish();
            startActivity(refreshIntent);
            return true;
        case R.id.action_settings:
            /* Opens up the SettingsActivity activity */
            Intent settingsIntent = new Intent(this, SettingsActivity.class);
            startActivity(settingsIntent);
            return true;
        case R.id.help:
            /* Opens up the HelpActivity activity */
            Intent helpIntent = new Intent(this, HelpActivity.class);
            startActivity(helpIntent);
            return true;
        case R.id.firmware_update:
            /* Creates the popup dialog for the firmware options */
            popupFirmware.createDialog();
            return true;
        default:
            return super.onOptionsItemSelected(item);

    }

}

private void setUpPages(Pages refPages) 
{
    Pages pagess = refPages;

    ArrayList<Page> arrayListPage = pagess.getPages();

    for(Page p : arrayListPage)
    {
        if(p == arrayListPage.get(0))
        {
            p = page1;
        }

        if(p == arrayListPage.get(1))
        {
            p = page2;
        }

        if(p == arrayListPage.get(2))
        {
            p = page3;
        }
    }
}

}

这是片段代码：

public class Fragment_1 extends SherlockFragment
{
private View view;
private PVConfiguration pvConfiguration;
private SlidingTabsActivity slidingTabsActivity;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
    view = inflater.inflate(R.layout.fragment_pv, container, false);

    slidingTabsActivity = (SlidingTabsActivity) getSherlockActivity();

    return view;
}

@Override
public void onActivityCreated(Bundle savedInstanceState) 
{
    /* Creates the new views from the configuration class */
    pvConfiguration = new PVConfiguration(getSherlockActivity());
    pvConfiguration.setDeviceInfo(slidingTabsActivity.getDeviceInfo());
    pvConfiguration.setPage(slidingTabsActivity.getPage1());
    pvConfiguration.createView();
  super.onActivityCreated(savedInstanceState); 
}
}

Answer 1

使用工厂方法创建片段，并在初始化时传递它。另外，请不要忘记保存onSaveStateInstace通过制作对象onCreate

来获取它Parceable

 public class Fragment_1 extends SherlockFragment
    {
        private View view;
        private PVConfiguration pvConfiguration;
        private SlidingTabsActivity slidingTabsActivity;

        public static Fragment_1 newInstance(PVConfiguration pvConfiguration){
            Fragment_1 frag = new Fragment_1();
            frag.pvConfiguration =  pvConfiguration;
            return frag;
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
        {
            view = inflater.inflate(R.layout.fragment_pv, container, false);

            slidingTabsActivity = (SlidingTabsActivity) getSherlockActivity();

            return view;
        }

        @Override
        public void onActivityCreated(Bundle savedInstanceState)
        {
    /* Creates the new views from the configuration class */
            pvConfiguration = new PVConfiguration(getSherlockActivity());
            pvConfiguration.setDeviceInfo(slidingTabsActivity.getDeviceInfo());
            pvConfiguration.setPage(slidingTabsActivity.getPage1());
            pvConfiguration.createView();
            super.onActivityCreated(savedInstanceState);
        }
    }

使用Android中的ActionBarSherlock将对象从父Activity传递到Fragment

1 个答案: