我的TabHost中的FragmentActivity包含ViewPager，我遇到一个奇怪的问题。
问题在于，当我使用应用程序时关闭手机（按电源按钮），然后我转回手机，我的应用程序重新打开，此时我的TabHost丢失了。因此，关闭手机会导致TabHost消失。
我的猜测是我需要将tabHost状态保存在saveInstanceState对象中，并在onResume中恢复它我只知道它是如何完成的。这是FragmentActivity的代码：
public class TabsViewPagerFragmentActivity extends FragmentActivity implements ViewPager.OnPageChangeListener, TabHost.OnTabChangeListener
{
static final String TAG = TabsViewPagerFragmentActivity.class.getSimpleName();
private TabHost mTabHost;
private ViewPager mViewPager;
private HashMap<String, TabInfo> mapTabInfo;
public ViewPagerAdapter mPagerAdapter;
private TextView tvReportName, tvTabTitle;
private Button bBackToParameters;
private Dialog progressDialog;
private SGRaportManagerAppObj application;
private int numberOfTabs = 0;
private Display display;
public static final int POPUP_MARGIN = 6;
LeftSideMenu leftSideMenu;
public void NotifyTabActivityViewPagerAdapter()
{
mPagerAdapter.notifyDataSetChanged();
}
public ViewPagerAdapter getTabActivityViewPagerAdapter()
{
return mPagerAdapter;
}
public ViewPager getTabActivityViewPager()
{
return mViewPager;
}
public void setCurrentTabTitle (String title)
{
tvTabTitle.setText(title);
Log.d(TAG, "set tab title from activity: "+title);
}
/**
* Maintains extrinsic info of a tab's construct
*/
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;
}
}
/**
* A simple factory that returns dummy views to the Tabhost
*/
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)
*/
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
application = SGRaportManagerAppObj.getInstance();
display = ((WindowManager)getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
// Inflate the layout
setContentView(R.layout.tabs_screen_activity_layout);
tvTabTitle = (TextView) findViewById(R.id.tvTabName);
tvReportName = (TextView)findViewById(R.id.tvReportName);
tvReportName.setText(application.currentReport.getName()+ " - ");
bBackToParameters = (Button) findViewById(R.id.bBackToParameters);
leftSideMenu = (LeftSideMenu) findViewById(R.id.leftSideMenu);
applyOnClickListenerToLeftSideMenu();
findViewById(R.id.showLeftMenuButton).setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View v)
{
Display d = ((WindowManager)getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
int width = d.getWidth();
View panel = findViewById(R.id.leftSideMenu);
View appPanel = findViewById(R.id.appLayout);
if (panel.getVisibility() == View.GONE){
appPanel.setLayoutParams(new LinearLayout.LayoutParams(width, LayoutParams.FILL_PARENT));
panel.setVisibility(View.VISIBLE);
applyOnClickListenerToLeftSideMenu();
}else{
ToggleButton button = (ToggleButton) findViewById(R.id.showLeftMenuButton);
button.setChecked(false);
panel.setVisibility(View.GONE);
}
}
});
// Initialise the TabHost
progressDialog = DialogUtils.createProgressDialog(this, this.getString(R.string.populating_view_pager));
progressDialog.show();
if (SGRaportManagerAppObj.getInstance().parametersRepository.getParametersRepository().size() == 0)
{
bBackToParameters.setText(R.string.back_to_report_list);
}
this.initialiseTabHost(savedInstanceState);
if (savedInstanceState != null) {
mTabHost.setCurrentTabByTag(savedInstanceState.getString("tab")); //set the tab as per the saved state
}
// Intialise ViewPager
this.intialiseViewPager();
progressDialog.dismiss();
}
/** (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);
}
/**
* Initialise ViewPager
*/
public void intialiseViewPager()
{
List<Fragment> fragments = new Vector<Fragment>();
// TabInfo tabInfo = null;
if (application.getCurrentDataSource().equals(DataSource.SSRS))
{
numberOfTabs = application.currentReport.getTabsList().size();
}
else if (application.getCurrentDataSource().equals(DataSource.SGRDL))
{
numberOfTabs = application.currentReport.getODTabsList().size();
Log.d(TAG, "CURRENT REPORT FROM VIEW PAGER: "+ application.currentReport.toString());
}
Log.d(TAG,"Current Tabs number from TabsViewPager activity: " +numberOfTabs);
if (application.getCurrentDataSource().equals(DataSource.SSRS))
{
for (int i = 0; i < numberOfTabs; i++)
{
Tab tempTab = application.currentReport.getTabsList().get(i);
if (tempTab.getTabTemplateId() == 7)
{
GridFragment gridFragment = new GridFragment(tempTab);
fragments.add(gridFragment);
}
else if (tempTab.getTabTemplateId() == 8)
{
NewChartFragment chartFragment = new NewChartFragment(tempTab, this);
fragments.add(chartFragment);
}
}
}
else if (application.getCurrentDataSource().equals(DataSource.SGRDL))
{
for (int i = 0; i < numberOfTabs; i++)
{
ODTab tempTab = application.currentReport.getODTabsList().get(i);
if (tempTab.getTabType().equals(ODGrid.XML_GRID_ELEMENT))
{
GridFragment gridFragment = GridFragment.newInstance(tempTab.getTabId());
fragments.add(gridFragment);
}
else if (tempTab.getTabType().equals(ODChart.XML_CHART_ELEMENT))
{
NewChartFragment chartFragment = NewChartFragment.newInstance(tempTab.getTabId());
fragments.add(chartFragment);
}
}
}
Log.d(TAG, "Current report fragments set to adapter: "+fragments.toString());
/*
if (this.mPagerAdapter == null)
{
this.mPagerAdapter = new ViewPagerAdapter(super.getSupportFragmentManager(), fragments);
}
else
{
this.mPagerAdapter.removeAllFragments();
this.mPagerAdapter.addFragmentsListToAdapter(fragments);
}
*/
this.mPagerAdapter = new ViewPagerAdapter(super.getSupportFragmentManager(), fragments);
this.mViewPager = (ViewPager)super.findViewById(R.id.pager);
// this.mViewPager.setAdapter(null);
this.mViewPager.setAdapter(this.mPagerAdapter);
this.mViewPager.setOffscreenPageLimit(0);
this.mViewPager.setOnPageChangeListener(this);
Log.d(TAG, "Adapter initialized!");
}
/**
* Initialise the Tab Host
*/
public void initialiseTabHost(Bundle args) {
mTabHost = (TabHost)findViewById(android.R.id.tabhost);
/*
//new edit
if (mTabHost.getChildCount() > 0)
{
mTabHost.removeAllViews();
}
*/
mTabHost.setup();
TabInfo tabInfo = null;
mapTabInfo = new HashMap<String, TabsViewPagerFragmentActivity.TabInfo>();
if (args != null)
{}
else
{
if (application.getCurrentDataSource().equals(DataSource.SSRS))
{
int numberOfTabs = application.currentReport.getTabsList().size();
for (int i = 0; i < numberOfTabs; i++)
{
Tab tempTab = application.currentReport.getTabsList().get(i);
if (tempTab.getTabTemplateId() == 7)
{
//GridFragment gridFragment = new GridFragment(tempTab);
TabsViewPagerFragmentActivity.AddTab(this, this.mTabHost, this.mTabHost.newTabSpec("Tab "+String.valueOf(i)).setIndicator("Tab "+String.valueOf(i)), ( tabInfo = new TabInfo("Tab "+String.valueOf(i), GridFragment.class, args)));
this.mapTabInfo.put(tabInfo.tag, tabInfo);
}
else if (tempTab.getTabTemplateId() == 8)
{
TabsViewPagerFragmentActivity.AddTab(this, this.mTabHost, this.mTabHost.newTabSpec("Tab "+String.valueOf(i)).setIndicator("Tab "+String.valueOf(i)), ( tabInfo = new TabInfo("Tab "+String.valueOf(i), NewChartFragment.class, args)));
this.mapTabInfo.put(tabInfo.tag, tabInfo);
}
}
}
else if (application.getCurrentDataSource().equals(DataSource.SGRDL))
{
int numberOfTabs = application.currentReport.getODTabsList().size();
for (int i = 0; i < numberOfTabs; i++)
{
ODTab tempTab = application.currentReport.getODTabsList().get(i);
// Log.d(TAG,"Crashed Tab type: "+ tempTab.getTabType());
if (tempTab.getTabType().equals(ODGrid.XML_GRID_ELEMENT))
{
//GridFragment gridFragment = new GridFragment(tempTab);
TabsViewPagerFragmentActivity.AddTab(this, this.mTabHost, this.mTabHost.newTabSpec("Tab "+String.valueOf(i)).setIndicator("Tab "+String.valueOf(i)), ( tabInfo = new TabInfo("Tab "+String.valueOf(i), GridFragment.class, args)));
this.mapTabInfo.put(tabInfo.tag, tabInfo);
}
else if (tempTab.getTabType().equals(ODChart.XML_CHART_ELEMENT))
{
TabsViewPagerFragmentActivity.AddTab(this, this.mTabHost, this.mTabHost.newTabSpec("Tab "+String.valueOf(i)).setIndicator("Tab "+String.valueOf(i)), ( tabInfo = new TabInfo("Tab "+String.valueOf(i), NewChartFragment.class, args)));
this.mapTabInfo.put(tabInfo.tag, tabInfo);
}
}
}
}
// Default to first tab
//this.onTabChanged("Tab1");
//
mTabHost.setOnTabChangedListener(this);
}
/**
* Add Tab content to the Tabhost
* @param activity
* @param tabHost
* @param tabSpec
* @param clss
* @param args
*/
private static void AddTab(TabsViewPagerFragmentActivity activity, TabHost tabHost, TabHost.TabSpec tabSpec, TabInfo tabInfo)
{
// Attach a Tab view factory to the spec
ImageView indicator = new ImageView(activity.getBaseContext());
indicator.setPadding(10, 10, 10, 10);
indicator.setImageResource(R.drawable.tab_select_icon_selector);
LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
lp.setMargins(10, 10, 10, 10);
indicator.setLayoutParams(lp);
tabSpec.setIndicator(indicator);
tabSpec.setContent(activity.new TabFactory(activity));
tabHost.addTab(tabSpec);
}
/** (non-Javadoc)
* @see android.widget.TabHost.OnTabChangeListener#onTabChanged(java.lang.String)
*/
public void onTabChanged(String tag) {
//TabInfo newTab = this.mapTabInfo.get(tag);
int pos = this.mTabHost.getCurrentTab();
this.mViewPager.setCurrentItem(pos);
}
/* (non-Javadoc)
* @see android.support.v4.view.ViewPager.OnPageChangeListener#onPageScrolled(int, float, int)
*/
@Override
public void onPageScrolled(int position, float positionOffset,
int positionOffsetPixels) {
// TODO Auto-generated method stub
}
/* (non-Javadoc)
* @see android.support.v4.view.ViewPager.OnPageChangeListener#onPageSelected(int)
*/
@Override
public void onPageSelected(int position) {
// TODO Auto-generated method stub
this.mTabHost.setCurrentTab(position);
}
/* (non-Javadoc)
* @see android.support.v4.view.ViewPager.OnPageChangeListener#onPageScrollStateChanged(int)
*/
@Override
public void onPageScrollStateChanged(int state) {
// TODO Auto-generated method stub
}
如何保存TabHost的状态并将其恢复为onResume？
非常感谢任何帮助。
答案 0 :(得分：1)
当手机进入睡眠状态onPause并且onStop被叫时，但onDestroy不会在重新打开手机时不会调用onCreate。
onRestart，onStart和onResume会被调用（通过修改活动生命周期培训应用程序在Nexus 7上检查以在所有生命周期方法中添加日志消息），因此请尝试移动尽可能多的您可以initialiseTabHost到onCreate中的onStart中的代码，只留下onCreate中所需的最小值，或将其保留在那里并将其相关部分添加到{{1} }}
更新（Emil Adz）：
如您所建议，我添加了onRestart方法并将其更改如下：
onResume从我的检查看起来好像它解决了我的问题，非常感谢。
编辑（朱利安）：查看您的@Override
protected void onResume() {
super.onResume();
if (mTabHost == null)
{
this.initialiseTabHost(null);
}
}
我想知道为什么mTabHost是onResume。我预计它不会出现由于某些初始化需要在null之后完成，但我没想到它会完全消失。
理想情况下，我们应该找出mTabHost最终为onStop的原因，问题是我无法重现该错误。如果我删除了我无法访问的每个类的代码，我会得到以下活动，显示3个选项卡，当我将设备置于睡眠状态并将其唤醒时仍显示它们：
null我使用了这种布局（来自http://getquery.com/android-fragment-tab-example/）：
package com.example.tabhost;
import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.view.ViewPager;
import android.util.Log;
import android.view.Display;
import android.view.View;
import android.view.WindowManager;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TabHost;
import android.widget.TabHost.TabContentFactory;
import android.widget.TextView;
public class TabsViewPagerFragmentActivity extends FragmentActivity implements ViewPager.OnPageChangeListener, TabHost.OnTabChangeListener
{
static final String TAG = TabsViewPagerFragmentActivity.class.getSimpleName();
private TabHost mTabHost; // TabHost? Why not a FragmentTabHost?
private ViewPager mViewPager;
private TextView tvTabTitle;
private Display display;
public static final int POPUP_MARGIN = 6;
public void NotifyTabActivityViewPagerAdapter() {}
public boolean getTabActivityViewPagerAdapter()
{
return true;
}
public ViewPager getTabActivityViewPager()
{
return mViewPager;
}
public void setCurrentTabTitle (String title)
{
tvTabTitle.setText(title);
Log.d(TAG, "set tab title from activity: "+title);
}
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;
public TabFactory(Context context) {
mContext = context;
}
public View createTabContent(String tag) {
View v = new View(mContext);
v.setMinimumWidth(0);
v.setMinimumHeight(0);
return v;
}
}
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
display = ((WindowManager)getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
// Inflate the layout
setContentView(R.layout.activity_main);
// Initialise the TabHost
this.initialiseTabHost(savedInstanceState);
if (savedInstanceState != null) {
mTabHost.setCurrentTabByTag(savedInstanceState.getString("tab")); //set the tab as per the saved state
}
}
protected void onSaveInstanceState(Bundle outState) {
outState.putString("tab", mTabHost.getCurrentTabTag()); //save the tab selected
super.onSaveInstanceState(outState);
}
public void initialiseTabHost(Bundle args) {
mTabHost = (TabHost)findViewById(android.R.id.tabhost);
/*
* Why not use a FragmentTabHost and setup (Context context, FragmentManager manager, int containerId)
* see: http://getquery.com/android-fragment-tab-example/
*/
mTabHost.setup();
int numberOfTabs = 3;//application.currentReport.getTabsList().size();
for (int i = 0; i < numberOfTabs; i++)
{
String str = "Tab " + String.valueOf(i);
TabsViewPagerFragmentActivity.AddTab(this, this.mTabHost, this.mTabHost.newTabSpec(str).setIndicator(str), null);
}
mTabHost.setOnTabChangedListener(this);
}
private static void AddTab(TabsViewPagerFragmentActivity activity, TabHost tabHost, TabHost.TabSpec tabSpec, TabInfo tabInfo)
{
// Attach a Tab view factory to the spec
ImageView indicator = new ImageView(activity.getBaseContext());
indicator.setPadding(10, 10, 10, 10);
indicator.setImageResource(R.drawable.ic_launcher);
LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,
LinearLayout.LayoutParams.WRAP_CONTENT);
lp.setMargins(10, 10, 10, 10);
indicator.setLayoutParams(lp);
tabSpec.setIndicator(indicator);
tabSpec.setContent(activity.new TabFactory(activity));
tabHost.addTab(tabSpec);
}
@Override
public void onStart() {
super.onStart();
Log.e("onStart", "mTabHost = " + mTabHost);
}
public void onTabChanged(String tag) {
//TabInfo newTab = this.mapTabInfo.get(tag);
int pos = this.mTabHost.getCurrentTab();
this.mViewPager.setCurrentItem(pos);
}
@Override
public void onPageScrolled(int position, float positionOffset,
int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
this.mTabHost.setCurrentTab(position);
}
@Override
public void onPageScrollStateChanged(int state) {
}
}
该代码是否适用于您的设备或您的标签仍然消失？