这是此问题的后续内容：Android - why is this telling me "Content view not yet created"?
因此，以下代码会引发错误：
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
LinearLayout Layout5 = (LinearLayout) inflater.inflate(R.layout.tab_frag5_layout, container, false);
Cursor allBands;
MyDatabase db;
Context ctx = (Context)TabFragment5.this.getActivity();
db = new MyDatabase(ctx);
allBands = db.getBands();
ListAdapter adapter = new SimpleCursorAdapter (ctx,
R.layout.listelement,
allBands,
new String[] {"BandName"},
new int[] {R.id.text15});
getListView().setAdapter(adapter);
return Layout5;
}
，但 如果我在布局中添加一个按钮并将代码放在OnClick方法中，它就可以完美地工作。像这样：
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
LinearLayout Layout5 = (LinearLayout) inflater.inflate(R.layout.tab_frag5_layout, container, false);
// Register for the Button.OnClick event
Button bShop = (Button)Layout5.findViewById(R.id.button_test);
bShop.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Cursor allBands;
MyDatabase db;
Context ctx = (Context)TabFragment5.this.getActivity();
db = new MyDatabase(ctx);
allBands = db.getBands();
ListAdapter adapter = new SimpleCursorAdapter (ctx,
R.layout.listelement,
allBands,
new String[] {"BandName"},
new int[] {R.id.text15});
getListView().setAdapter(adapter);
}
});
return Layout5;
为什么会这样。我知道它必须与片段生命周期有关，但是什么？我怎样才能避免这种情况，以便在片段打开时填充列表列表视图，而不仅仅是当我点击按钮时？
由于
编辑：这是主要活动
public class TabsFragmentActivity extends FragmentActivity implements TabHost.OnTabChangeListener {
private TabHost mTabHost;
private HashMap mapTabInfo = new HashMap();
private TabInfo mLastTab = null;
private class TabInfo {
private String tag;
private Class clss;
private Bundle args;
private Fragment fragment;
TabInfo(String tag, Class clazz, Bundle args) {
this.tag = tag;
this.clss = clazz;
this.args = args;
}
}
class TabFactory implements TabContentFactory {
private final Context mContext;
/**
* @param context
*/
public TabFactory(Context context) {
mContext = context;
}
/** (non-Javadoc)
* @see android.widget.TabHost.TabContentFactory#createTabContent(java.lang.String)
*/
public View createTabContent(String tag) {
View v = new View(mContext);
v.setMinimumWidth(0);
v.setMinimumHeight(0);
return v;
}
}
/** (non-Javadoc)
* @see android.support.v4.app.FragmentActivity#onCreate(android.os.Bundle)
*/
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Step 1: Inflate layout
setContentView(R.layout.tabs_layout);
// Step 2: Setup TabHost
initialiseTabHost(savedInstanceState);
if (savedInstanceState != null) {
mTabHost.setCurrentTabByTag(savedInstanceState.getString("tab")); //set the tab as per the saved state
}
}
/** (non-Javadoc)
* @see android.support.v4.app.FragmentActivity#onSaveInstanceState(android.os.Bundle)
*/
protected void onSaveInstanceState(Bundle outState) {
outState.putString("tab", mTabHost.getCurrentTabTag()); //save the tab selected
super.onSaveInstanceState(outState);
}
/**
* Step 2: Setup TabHost
*/
private void initialiseTabHost(Bundle args) {
mTabHost = (TabHost)findViewById(android.R.id.tabhost);
mTabHost.setup();
TabInfo tabInfo = null;
TabsFragmentActivity.addTab(this, this.mTabHost, this.mTabHost.newTabSpec("Tab1").setIndicator("s1"), ( tabInfo = new TabInfo("Tab1", TabFragment1.class, args)));
this.mapTabInfo.put(tabInfo.tag, tabInfo);
TabsFragmentActivity.addTab(this, this.mTabHost, this.mTabHost.newTabSpec("Tab2").setIndicator("s2"), ( tabInfo = new TabInfo("Tab2", TabFragment2.class, args)));
this.mapTabInfo.put(tabInfo.tag, tabInfo);
TabsFragmentActivity.addTab(this, this.mTabHost, this.mTabHost.newTabSpec("Tab3").setIndicator("s3"), ( tabInfo = new TabInfo("Tab3", TabFragment3.class, args)));
this.mapTabInfo.put(tabInfo.tag, tabInfo);
TabsFragmentActivity.addTab(this, this.mTabHost, this.mTabHost.newTabSpec("Tab4").setIndicator("s4"), ( tabInfo = new TabInfo("Tab4", TabFragment4.class, args)));
this.mapTabInfo.put(tabInfo.tag, tabInfo);
TabsFragmentActivity.addTab(this, this.mTabHost, this.mTabHost.newTabSpec("Tab5").setIndicator("s5"), ( tabInfo = new TabInfo("Tab5", TabFragment5.class, args)));
this.mapTabInfo.put(tabInfo.tag, tabInfo);
TabsFragmentActivity.addTab(this, this.mTabHost, this.mTabHost.newTabSpec("Tab6").setIndicator("s6"), ( tabInfo = new TabInfo("Tab6", TabFragment6.class, args)));
this.mapTabInfo.put(tabInfo.tag, tabInfo);
// Default to first tab
this.onTabChanged("Tab1");
//
mTabHost.setOnTabChangedListener(this);
}
/**
* @param activity
* @param tabHost
* @param tabSpec
* @param clss
* @param args
*/
private static void addTab(TabsFragmentActivity activity, TabHost tabHost, TabHost.TabSpec tabSpec, TabInfo tabInfo) {
// Attach a Tab view factory to the spec
tabSpec.setContent(activity.new TabFactory(activity));
String tag = tabSpec.getTag();
// Check to see if we already have a fragment for this tab, probably
// from a previously saved state. If so, deactivate it, because our
// initial state is that a tab isn't shown.
tabInfo.fragment = activity.getSupportFragmentManager().findFragmentByTag(tag);
if (tabInfo.fragment != null && !tabInfo.fragment.isDetached()) {
FragmentTransaction ft = activity.getSupportFragmentManager().beginTransaction();
ft.detach(tabInfo.fragment);
ft.commit();
activity.getSupportFragmentManager().executePendingTransactions();
}
tabHost.addTab(tabSpec);
}
/** (non-Javadoc)
9
* @see android.widget.TabHost.OnTabChangeListener#onTabChanged(java.lang.String)
*/
public void onTabChanged(String tag) {
TabInfo newTab = (TabInfo) this.mapTabInfo.get(tag);
if (mLastTab != newTab) {
FragmentTransaction ft = this.getSupportFragmentManager().beginTransaction();
if (mLastTab != null) {
if (mLastTab.fragment != null) {
ft.detach(mLastTab.fragment);
}
}
if (newTab != null) {
if (newTab.fragment == null) {
newTab.fragment = Fragment.instantiate(this,
newTab.clss.getName(), newTab.args);
ft.add(R.id.realtabcontent, newTab.fragment, newTab.tag);
} else {
ft.attach(newTab.fragment);
}
}
mLastTab = newTab;
ft.commit();
this.getSupportFragmentManager().executePendingTransactions();
}
}
}
片段XML
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/mylayout2"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#D6D6D6"
>
<Button
android:id="@+id/button_test"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0"
android:text="Button" />
<ListView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="0"
android:id="@android:id/list"></ListView>
答案 0 :(得分：4)
这里的关键是在ListFragment中调用setAdapter（）时。
在你的第一个例子中，setAdapter（）在onCreateView（）内被调用，因为ListFragment检查以确保在允许设置适配器之前在布局中定义了一个列表，直到onCreateView（ ）返回您正在创建的视图，没有要检查的布局。这是鸡和蛋的问题。
第二个例子起作用的原因是因为你实际上并没有从onCreateView（）中调用setAdapter（）。在生成的布局中单击按钮之前，不会设置适配器。
这里的基本问题是片段与活动的不同之处在于，您不能像处理活动那样在onCreate（）中执行相同类型的操作，尤其是在设置适配器时
答案 1 :(得分：1)
您是否扩展了Fragment Class或ListFragment？ 这就是我在ListFragment中使用它的方法 - ＆gt;
public class FooFragment extends ListFragment{
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View root = inflater.inflate(R.layout.fragment_eventlist, null);
eventAdapter = new EventAdapter(getActivity(), R.layout.list_item_event, events);
setListAdapter(eventAdapter);
return root;
}
}
编辑：
只需修改变量和类型：
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View root = inflater.inflate(R.layout.fragment_activitystream, null);
return root;
}
@Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
states = new ArrayList<Status>();
...
YourAdapter asa = new YourAdapter(getActivity(), R.layout.list_item_status, states);
setListAdapter(asa);
Log.i(TAG, "onCreate is done");
}