我正在尝试单击另一个片段上的按钮来更新片段中的 TextView。
实际上，我对 Activity 实现了回调函数，并且它确实有效，因为 Logcat 报告 TextView 中的文本已更改。问题是第一个片段中显示的 Textview 没有更新为新值！就像 Fragment 需要更新什么的......
这是 ActionBarTabsPager 活动代码：
import java.util.ArrayList;
import android.app.Activity;
import android.app.FragmentManager;
import android.app.FragmentManager.OnBackStackChangedListener;
import android.content.Context;
import android.os.Build;
import android.os.Bundle;
import android.support.v4.app.ActionBar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.app.ActionBar.Tab;
import android.support.v4.app.SupportActivity;
import android.support.v4.view.ViewPager;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.View.OnClickListener;
import android.widget.TextView;
/**
* Demonstrates combining the action bar with a ViewPager to implement a tab UI
* that switches between tabs and also allows the user to perform horizontal
* flicks to move between the tabs.
*/
public class ActionBarTabsPager extends FragmentActivity implements SecondFragment.OnButtonClickedXListener{
ViewPager mViewPager;
TabsAdapter mTabsAdapter;
FragmentManager fm;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.actionbar_tabs_pager);
if (savedInstanceState == null) {
Fragment newFragment = new FirstFragment();
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.add(R.id.abs__custom, newFragment, "FirstFragment").commit();
Fragment newFragment2 = new FirstFragment();
FragmentTransaction ft2 = getSupportFragmentManager().beginTransaction();
ft2.add(R.id.abs__custom, newFragment2, "SecondFragment").commit();
}
getSupportActionBar().setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
ActionBar.Tab tab1 = getSupportActionBar().newTab().setText("Fragment 1");
ActionBar.Tab tab2 = getSupportActionBar().newTab().setText("Fragment 2");
//ActionBar.Tab tab3 = getSupportActionBar().newTab().setText("Fragment 1");
//ActionBar.Tab tab4 = getSupportActionBar().newTab().setText("Fragment 2");
mViewPager = (ViewPager)findViewById(R.id.pager);
mTabsAdapter = new TabsAdapter(this, getSupportActionBar(), mViewPager);
mTabsAdapter.addTab(tab1, FirstFragment.class);
mTabsAdapter.addTab(tab2, SecondFragment.class);//LoaderCursorSupport.CursorLoaderListFragment.class);
//mTabsAdapter.addTab(tab3, FirstFragment.class);//LoaderCustomSupport.AppListFragment.class);
//mTabsAdapter.addTab(tab4, SecondFragment.class);//LoaderThrottleSupport.ThrottledLoaderListFragment.class);
if (savedInstanceState != null) {
getSupportActionBar().setSelectedNavigationItem(savedInstanceState.getInt("index"));
}
}
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putInt("index", getSupportActionBar().getSelectedNavigationIndex());
}
/**
* This is a helper class that implements the management of tabs and all
* details of connecting a ViewPager with associated TabHost. It relies on a
* trick. Normally a tab host has a simple API for supplying a View or
* Intent that each tab will show. This is not sufficient for switching
* between pages. So instead we make the content part of the tab host
* 0dp high (it is not shown) and the TabsAdapter supplies its own dummy
* view to show as the tab content. It listens to changes in tabs, and takes
* care of switch to the correct paged in the ViewPager whenever the selected
* tab changes.
*/
public class TabsAdapter extends FragmentPagerAdapter implements ViewPager.OnPageChangeListener, ActionBar.TabListener {
private final Context mContext;
private final ActionBar mActionBar;
private final ViewPager mViewPager;
private final ArrayList<String> mTabs = new ArrayList<String>();
public TabsAdapter(FragmentActivity activity, ActionBar actionBar, ViewPager pager) {
super(activity.getSupportFragmentManager());
mContext = activity;
mActionBar = actionBar;
mViewPager = pager;
mViewPager.setAdapter(this);
mViewPager.setOnPageChangeListener(this);
}
public void addTab(ActionBar.Tab tab, Class<?> clss) {
mTabs.add(clss.getName());
mActionBar.addTab(tab.setTabListener(this));
notifyDataSetChanged();
}
@Override
public int getCount() {
return mTabs.size();
}
@Override
public Fragment getItem(int position) {
return Fragment.instantiate(mContext, mTabs.get(position), null);
}
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
mActionBar.setSelectedNavigationItem(position);
}
@Override
public void onPageScrollStateChanged(int state) {
}
@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
mViewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
}
@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
}
}
@Override
public void OnButtonClickedX(View v) {
if (v==findViewById(R.id.button1)){
Log.i("TRIGGERED","TRIGGERED");
FirstFragment ff = (FirstFragment) getSupportFragmentManager().findFragmentByTag("FirstFragment");
View root = ff.getView();
TextView tv = (TextView) root.findViewById(R.id.textView1);
Log.i("Text before Edit",""+tv.getText());
tv.setText("MODIFIED");
Log.i("Text after Edit",""+tv.getText());
}
// TODO Auto-generated method stub
}
}
第一个片段：
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class FirstFragment extends Fragment {
int mNum;
/**
* Create a new instance of FirstFragment, providing "num"
* as an argument.
*/
static FirstFragment newInstance(int num) {
FirstFragment f = new FirstFragment();
// Supply num input as an argument.
Bundle args = new Bundle();
args.putInt("num", num);
f.setArguments(args);
return f;
}
/**
* When creating, retrieve this instance's number from its arguments.
*/
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mNum = getArguments() != null ? getArguments().getInt("num") : 1;
}
/**
* The Fragment's UI is just a simple text view showing its
* instance number.
*/
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.myfrag1, container, false);
return v;
}
}
第二个片段：
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.SupportActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
public class SecondFragment extends Fragment {
int mNum;
OnButtonClickedXListener mListener;
/**
* Create a new instance of CountingFragment, providing "num"
* as an argument.
*/
static SecondFragment newInstance(int num) {
SecondFragment f = new SecondFragment();
// Supply num input as an argument.
Bundle args = new Bundle();
args.putInt("num", num);
f.setArguments(args);
return f;
}
/**
* When creating, retrieve this instance's number from its arguments.
*/
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mNum = getArguments() != null ? getArguments().getInt("num") : 1;
}
/**
* The Fragment's UI is just a simple text view showing its
* instance number.
*/
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.myfrag2, container, false);
View button1 = v.findViewById(R.id.button1);
button1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
mListener.OnButtonClickedX(v);
// TODO Auto-generated method stub
}
});
return v;
}
public interface OnButtonClickedXListener{
public void OnButtonClickedX(View v);
}
@Override
public void onAttach(SupportActivity activity) {
// TODO Auto-generated method stub
super.onAttach(activity);
try {
mListener = (OnButtonClickedXListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString() + " must implement OnButtonClickedXListener");
}
}
}
myfrag1.xml：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/textView1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center"
android:text="No String"
android:textAppearance="?android:attr/textAppearanceLarge" />
</LinearLayout>
myfrag2.xml：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<Button
android:id="@+id/button1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:gravity="center"
android:text="Button" />
</LinearLayout>
EDIT:
即使将 ft.add() 中的 ContainerViewId 更改为 0，也不会影响最终渲染。所以我猜渲染是由
mTabsAdapter.addTab(tab1, FirstFragment.class);
mTabsAdapter.addTab(tab2, SecondFragment.class);
无论如何，问题仍然是一样的。
Here's actionbar_tabs_pager.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/pager"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
/>
