我正在尝试让两个 Fragment 通过 Activity 中的接口(interface)相互通信。当在带有 ListView 的 Fragment 中单击一行时，它会向 Activity 发送一个 ID，然后需要将其传递并调用另一个 Fragment 中的方法。 fragment 是 ViewPager 的一部分，因为它们是可交换的选项卡。
当前创建第二个 Fragment 会导致应用程序崩溃，因为我试图将其放入布局中，而不是我认为的容器中。
所以，我需要获取 WebViewFragment 的 Container，这样我就可以使用 FragmentTransaction 并将其放入容器中 - 是这样吗正确的？如果是这样，我如何获得容器？
MyPagerAdapter:
public class TabsPagerAdapter extends FragmentPagerAdapter {
public TabsPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
switch(position) {
case 0:
return new SfnViewerFragment();
case 1:
return new DirectoryFragment();
case 2:
return new HelpFragment();
}
return null;
}
@Override
public int getCount() {
return 3;
}
}
ListViewFragment:
public class DirectoryFragment extends Fragment {
SimpleCursorAdapter adapter;
Cursor cursor;
OnViewerSelectedListener mCallback;
// Interface to send Id of viewer to activity, which is then passed
// To the fragment containing the WebView
public interface OnViewerSelectedListener {
public void onViewerSelected(Long id);
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
// Make sure the container activity has implemented the interface.
// If it hasn't throw and exception.
try {
mCallback = (OnViewerSelectedListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement OnViewerSelectedListener");
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_directory, container, false);
ListView listView = (ListView) rootView.findViewById(R.id.list);
DatabaseHelper dbHelper = new DatabaseHelper(getActivity());
// Use a cursor adapter to tie database info with the ListView
final SimpleCursorAdapter adapter = new SimpleCursorAdapter(getActivity(), android.R.layout.simple_list_item_1, dbHelper.getViewers(), new String[] { "description", "_id" }, new int[] { android.R.id.text1 }, CursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER);
listView.setAdapter(adapter);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
Long id = adapter.getItemId(i);
mCallback.onViewerSelected(id);
}
});
return rootView;
}
}
主要 Activity :
public class MainActivity extends FragmentActivity implements ActionBar.TabListener, DirectoryFragment.OnViewerSelectedListener {
private ViewPager viewPager;
private TabsPagerAdapter mAdapter;
private ActionBar actionBar;
//Tab Titles
private String[] tabs = { "sfn Viewer", "Directory", "Help" };
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DatabaseHelper db = new DatabaseHelper(this);
//Initialization
viewPager = (ViewPager) findViewById(R.id.pager);
actionBar = getActionBar();
mAdapter = new TabsPagerAdapter(getSupportFragmentManager());
viewPager.setAdapter(mAdapter);
actionBar.setHomeButtonEnabled(false);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
//Adding Tabs
for (String tab_name : tabs) {
actionBar.addTab(actionBar.newTab().setText(tab_name).setTabListener(this));
}
viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageSelected(int position) {
//On changing page, make sure right tab is selected
actionBar.setSelectedNavigationItem(position);
}
@Override
public void onPageScrolled(int arg0, float arg1, int arg2) {}
@Override
public void onPageScrollStateChanged(int arg0) {}
});
}
@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;
}
@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();
if (id == R.id.action_settings) {
Toast.makeText(this, "Settings selected", Toast.LENGTH_SHORT).show();
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void onViewerSelected(Long id) {
SfnViewerFragment sfnViewerFragment = (SfnViewerFragment)
getSupportFragmentManager().findFragmentByTag("android:switcher:" + R.id.pager + ":0");
sfnViewerFragment.getWebView(id);
//viewPager.setCurrentItem(0, true);
}
@Override
public void onTabSelected(ActionBar.Tab tab, android.app.FragmentTransaction fragmentTransaction) {
//When the tab is selected show the correct fragment
viewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(ActionBar.Tab tab, android.app.FragmentTransaction fragmentTransaction) {
}
@Override
public void onTabReselected(ActionBar.Tab tab, android.app.FragmentTransaction fragmentTransaction) {
}
}
WebViewFragment:
public class SfnViewerFragment extends Fragment {
private WebView webView;
private View rootView;
private HashMap<Long, WebView> webViews;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
rootView = inflater.inflate(R.layout.fragment_sfn_viewer, container, false);
return rootView;
}
public void getWebView(Long id) {
if (!webViews.containsKey(id)) {
createWebView(id);
webView = webViews.get(id);
webView.setVisibility(View.VISIBLE);
FrameLayout mWebContainer = (FrameLayout) getView().findViewById(R.id.web_container);
mWebContainer.addView(webView);
} else {
webView = webViews.get(id);
webView.setVisibility(View.VISIBLE);
FrameLayout mWebContainer = (FrameLayout) getView().findViewById(R.id.web_container);
mWebContainer.addView(webView);
}
}
public void createWebView(Long id) {
WebView wv = new WebView(getActivity());
wv.setWebViewClient(new WebViewClient() {
@Override
public void onPageFinished(WebView view, String url) {
view.loadUrl("javascript:(registerCredentialsChangedCallback(function(credentials) {if (credentials.length >= 1) {window.location.href = 'callback:' + credentials;} else {alert('Error: callback set by registerCredentialsChangedCallback was given null string');}})) ()");
}
});
WebSettings webSettings = wv.getSettings();
webSettings.setJavaScriptEnabled(true);
webSettings.setUseWideViewPort(true);
webSettings.setLoadWithOverviewMode(true);
wv.loadUrl(makeViewerURL(id));
webViews.put(id, wv);
Log.d("createWebView: ", "WebView Created.");
}
public String makeViewerURL(Long id) {
DatabaseHelper dbHelper = new DatabaseHelper(getActivity());
Viewer clickedViewer = dbHelper.getViewer(id);
String url = clickedViewer.getHostURL() + "/" + clickedViewer.getWebApp() + "/viewer?username=" +
clickedViewer.getUsername() + "&pw=" + clickedViewer.getPassword() + "&modelId=" + clickedViewer.getModelId() + "&" + clickedViewer.getProperties();
Log.d("Url is: ", url);
return url;
}
}
运行应用程序时出错:
java.lang.IllegalArgumentException: No view found for id 0x7f03001b (com.lightfootsolutions.sfnviewer.app:layout/fragment_sfn_viewer) for fragment SfnViewerFragment{b1f8d2e8 #3 id=0x7f03001b}
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:930)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1115)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1478)
at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:478)
at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1068)
at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:550)
at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:509)
at android.support.v4.view.ViewPager.setCurrentItem(ViewPager.java:501)
at com.lightfootsolutions.sfnviewer.app.MainActivity.onViewerSelected(MainActivity.java:120)
at com.lightfootsolutions.sfnviewer.app.DirectoryFragment$1.onItemClick(DirectoryFragment.java:79)
at android.widget.AdapterView.performItemClick(AdapterView.java:299)
at android.widget.AbsListView.performItemClick(AbsListView.java:1113)
at android.widget.AbsListView$PerformClick.run(AbsListView.java:2904)
at android.widget.AbsListView$3.run(AbsListView.java:3638)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
当我点击一行时，它会崩溃。
最佳答案
要使用新数据更新其他 fragment ，您不应执行新事务，因为该 fragment 位于 ViewPager 中。相反，获取对寻呼机 fragment 的引用并调用其更新方法并向其传递 id:
@Override
public void onViewerSelected(Long id) {
SfnViewerFragment sfnViewerFragment = (SfnViewerFragment)
getSupportFragmentManager().findFragmentByTag("android:switcher:" + R.id.pager + ":0");
sfnViewerFragment.getWebView(id);
}
关于java - 获取用于 FragmentTransaction 的 containerViewId，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/24700115/