我正试图在手机上禁用这个特定片段的硬件按钮。
片段：
public class Second_frag extends android.support.v4.app.Fragment {
String RSSFEEDURL = "http://feeds.feedburner.com/TwitterRssFeedXML?format=xml";
RSSFeed feed;
String fileName;
View myView;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
myView = inflater.inflate(R.layout.splash,container,false);
((AppCompatActivity) getActivity()).getSupportActionBar().hide();
fileName = "Feed.td";
File feedFile = getActivity().getBaseContext().getFileStreamPath(fileName);
ConnectivityManager conMgr = (ConnectivityManager) getActivity().getSystemService(Context.CONNECTIVITY_SERVICE);
if (conMgr.getActiveNetworkInfo() == null) {
// No connectivity. Check if feed File exists
if (!feedFile.exists()) {
// No connectivity & Feed file doesn't exist: Show alert to exit
// & check for connectivity
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
builder.setMessage(
"Unable to reach server, \nPlease check your connectivity.")
.setTitle("TD RSS Reader")
.setCancelable(false)
.setPositiveButton("Exit",
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog,
int id) {
getActivity().finish();
}
});
AlertDialog alert = builder.create();
alert.show();
} else {
// No connectivty and file exists: Read feed from the File
Toast.makeText(Second_frag.this.getActivity(), "No connectivity. Reading last update", Toast.LENGTH_LONG).show();
feed = ReadFeed(fileName);
startLisActivity(feed);
}
} else {
// Connected - Start parsing
new AsyncLoadXMLFeed().execute();
}
return myView;
}
private void startLisActivity(RSSFeed feed) {
Bundle bundle = new Bundle();
bundle.putSerializable("feed", feed);
List_Activity fragment = new List_Activity();
fragment.setArguments(bundle);
FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.replace(R.id.workdarnit, fragment).commit();
}
private class AsyncLoadXMLFeed extends AsyncTask<Void, Void, Void> {
@Override
protected Void doInBackground(Void... params) {
// Obtain feed
DOMParser myParser = new DOMParser();
feed = myParser.parseXml(RSSFEEDURL);
if (feed != null && feed.getItemCount() > 0)
WriteFeed(feed);
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
startLisActivity(feed);
}
}
// Method to write the feed to the File
private void WriteFeed(RSSFeed data) {
FileOutputStream fOut =null ;
ObjectOutputStream osw = null;
try {
fOut = getActivity().openFileOutput(fileName, Context.MODE_PRIVATE);
osw = new ObjectOutputStream(fOut);
osw.writeObject(data);
osw.flush();
}
catch (Exception e) {
e.printStackTrace();
}
finally {
try {
if(fOut !=null){
fOut.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
// Method to read the feed from the File
private RSSFeed ReadFeed(String fName) {
FileInputStream fIn = null;
ObjectInputStream isr = null;
RSSFeed _feed = null;
File feedFile = getActivity().getBaseContext().getFileStreamPath(fileName);
if (!feedFile.exists())
return null;
try {
fIn = getActivity().openFileInput(fName);
isr = new ObjectInputStream(fIn);
_feed = (RSSFeed) isr.readObject();
}
catch (Exception e) {
e.printStackTrace();
}
finally {
try {
if(fIn !=null){
fIn.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
return _feed;
}
}
我尝试在片段上添加onbackpress，但它不起作用。有谁知道如何解决这个问题？任何帮助将不胜感激。
编辑：
public class MainActivity extends AppCompatActivity
implements NavigationDrawerFragment.NavigationDrawerCallbacks {
/**
* Fragment managing the behaviors, interactions and presentation of the navigation drawer.
*/
private NavigationDrawerFragment mNavigationDrawerFragment;
/**
* Used to store the last screen title. For use in {@link #restoreActionBar()}.
*/
private CharSequence mTitle;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mNavigationDrawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
mTitle = getTitle();
// Set up the drawer.
mNavigationDrawerFragment.setUp(
R.id.navigation_drawer,
(DrawerLayout) findViewById(R.id.drawer_layout));
}
@Override
public void onNavigationDrawerItemSelected(int position) {
Fragment myFragment = null;
switch (position) {
case 0:
myFragment = new home();
break;
case 1:
myFragment = new First_frag();
break;
case 2:
myFragment = new Second_frag();
break;
case 3:
myFragment = new Third_frag();
break;
case 4:
myFragment = new First_frag_o();
break;
case 5:
myFragment = new QuizF();
break;
case 6:
myFragment = new Surv_list();
break;
}
// update the main content by replacing fragments
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.container, myFragment)
.commit();
}
public void onSectionAttached(int number) {
switch (number) {
case 1:
mTitle = getString(R.string.title_section1);
break;
case 2:
mTitle = getString(R.string.title_section2);
break;
case 3:
mTitle = getString(R.string.title_section3);
break;
case 4:
mTitle = getString(R.string.title_section4);
break;
case 5:
mTitle = getString(R.string.title_section5);
break;
case 6:
mTitle = getString(R.string.title_section6);
break;
case 7:
mTitle = getString(R.string.title_section7);
break;
}
}
public void restoreActionBar() {
ActionBar actionBar = getSupportActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
actionBar.setDisplayShowTitleEnabled(true);
actionBar.setTitle(mTitle);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
if (!mNavigationDrawerFragment.isDrawerOpen()) {
// Only show items in the action bar relevant to this screen
// if the drawer is not showing. Otherwise, let the drawer
// decide what to show in the action bar.
getMenuInflater().inflate(R.menu.main, menu);
restoreActionBar();
return true;
}
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
return rootView;
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
((MainActivity) activity).onSectionAttached(
getArguments().getInt(ARG_SECTION_NUMBER));
}
}
}
答案 0 :(得分：0)
您需要在onBackPressed（）方法的Activity中处理此问题。 在方法中，您可以查找片段，如果可见，则不执行任何操作。
如果没有看到框架，只需调用super.onBackPressed（）。
那应该有用。
答案 1 :(得分：0)
尝试这个技巧：
Main Activity
public class MainActivity extends AppCompatActivity
implements NavigationDrawerFragment.NavigationDrawerCallbacks {
/**
* Fragment managing the behaviors, interactions and presentation of the navigation drawer.
*/
private NavigationDrawerFragment mNavigationDrawerFragment;
/**
* Used to store the last screen title. For use in {@link #restoreActionBar()}.
*/
private CharSequence mTitle;
Boolean isSecFragmnet=false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mNavigationDrawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
mTitle = getTitle();
// Set up the drawer.
mNavigationDrawerFragment.setUp(
R.id.navigation_drawer,
(DrawerLayout) findViewById(R.id.drawer_layout));
}
@Override
public void onNavigationDrawerItemSelected(int position) {
Fragment myFragment = null;
switch (position) {
case 0:
myFragment = new home();
isSecFragmnet=false;
break;
case 1:
myFragment = new First_frag();
isSecFragmnet=false;
break;
case 2:
myFragment = new Second_frag();
isSecFragmnet=true;
break;
case 3:
myFragment = new Third_frag();
isSecFragmnet=false;
break;
case 4:
myFragment = new First_frag_o();
isSecFragmnet=false;
break;
case 5:
myFragment = new QuizF();
isSecFragmnet=false;
break;
case 6:
myFragment = new Surv_list();
isSecFragmnet=false;
break;
}
// update the main content by replacing fragments
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.container, myFragment)
.commit();
}
public void onSectionAttached(int number) {
switch (number) {
case 1:
mTitle = getString(R.string.title_section1);
break;
case 2:
mTitle = getString(R.string.title_section2);
break;
case 3:
mTitle = getString(R.string.title_section3);
break;
case 4:
mTitle = getString(R.string.title_section4);
break;
case 5:
mTitle = getString(R.string.title_section5);
break;
case 6:
mTitle = getString(R.string.title_section6);
break;
case 7:
mTitle = getString(R.string.title_section7);
break;
}
}
public void restoreActionBar() {
ActionBar actionBar = getSupportActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
actionBar.setDisplayShowTitleEnabled(true);
actionBar.setTitle(mTitle);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
if (!mNavigationDrawerFragment.isDrawerOpen()) {
// Only show items in the action bar relevant to this screen
// if the drawer is not showing. Otherwise, let the drawer
// decide what to show in the action bar.
getMenuInflater().inflate(R.menu.main, menu);
restoreActionBar();
return true;
}
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
return rootView;
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
((MainActivity) activity).onSectionAttached(
getArguments().getInt(ARG_SECTION_NUMBER));
}
}
@Override
public void onBackPressed() {
if (isSecFragment) {
//do nothing
Log.e("backpressed", "pressed");
} else
{
super.onBackPressed();
}
}
答案 2 :(得分：0)
只需将此添加到您的活动中：
TemplateFragment或者如果您更愿意片段来决定它是否会启用后退按钮，那么所有片段都希望扩展普通public class TemplateFragment extends android.support.v4.app.Fragment {
public boolean enableOnBackPressed() {
return true;
}
}
public class Second_frag extends TemplateFragment {
...
@Override
public final boolean enableOnBackPressed() {
return false;
}
}
：
@Override
public void onBackPressed() {
Fragment currFrag = getSupportFragmentManager().findFragmentById(R.id.container);
if (currFrag instanceof TemplateFragment) {
if (!((TemplateFragment) currFrag).enableOnBackPressed()) {
//do nothing
return;
}
}
super.onBackPressed();
}
以及活动中的内容：
ActionListener