問題描述

1,問題： 應用長期在后臺的場景下，進入前臺時，fragment顯示為空白2,app框架大體實現： 1個activity+多個Fragment,使用的是add（）方法以及 hide(),show()方法，顯示fragment3,相關代碼：

onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // 判斷 savedInstanceState是否為空: setCanResizeWindow(false); maskView = new View(getApplicationContext()); maskView.setBackground(new ColorDrawable(Color.parseColor('#30000000'))); maskView.setClickable(true); maskView.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) { removeMask();} }); setContentView(R.layout.activity_home); EventBus.getDefault().register(this); //3,個推 PushManager.getInstance().initialize(getApplicationContext()); initView(savedInstanceState); getUserData(); getDataFromMsgBrief();} private void initView(Bundle savedInstanceState) {mBottomDial = (LinearLayout) findViewById(R.id.btn_Dial);mBottomComm = (LinearLayout) findViewById(R.id.btn_comm);mBottomContact = (LinearLayout) findViewById(R.id.btn_contact);mBottomLife = (LinearLayout) findViewById(R.id.btn_life);mBottomDialIv = (ImageView) findViewById(R.id.tab_dial_image);mBottomDiaTv = (TextView) findViewById(R.id.tab_dial_text);mSmsIV = (SmsImageView) findViewById(R.id.siv_sms_icon_homeact);//第一次登錄系統時，修改數據庫的Istravelrely字段if (!SpUtils.getSynDB(getApplicationContext())) { ThreadPoolUtil.getmExecutor().execute(new Runnable() {@Overridepublic void run() { CopyLocalContactsUtils.checkIsTravelRely(getApplication()); SpUtils.setSynDB(getApplicationContext());} });}//初始化mBottomDial為選中狀態，fl_content填充DialFragmentmBottomDial.setSelected(true);//if (savedInstanceState != null) {// LogUtils.d('HomeActivity savedInstanceState != null');//// Fragment dialFragment = getSupportFragmentManager().findFragmentByTag(DIAL_TAG);// Fragment contactFragment = getSupportFragmentManager().findFragmentByTag(CONTACT_TAG);// Fragment commFragment = getSupportFragmentManager().findFragmentByTag(COMM_TAG);// Fragment lifeFragment = getSupportFragmentManager().findFragmentByTag(LIFE_TAG);//// getSupportFragmentManager().beginTransaction()//// getSupportFragmentManager().beginTransaction().hide(contactFragment)// .hide(commFragment).hide(lifeFragment).show(dialFragment).commit();////} else { getSupportFragmentManager().beginTransaction(). add(R.id.fl_content, FragmentFactory.createFragment(0), 'DialFragment'). add(R.id.fl_content, FragmentFactory.createFragment(1), 'CommFragment'). add(R.id.fl_content, FragmentFactory.createFragment(2), 'ContactFragment'). add(R.id.fl_content, FragmentFactory.createFragment(3), 'LifeFragment'). hide(FragmentFactory.createFragment(1)). hide(FragmentFactory.createFragment(2)). hide(FragmentFactory.createFragment(3)). show(FragmentFactory.createFragment(0)).commit();//}initClick(); }

嘗試過的解決辦法：1，為了解決多個fragment重疊顯示，在activity的中執行了如下：

@Override protected void onSaveInstanceState(Bundle outState) {//super.onSaveInstanceState(outState); }

問題現象：

問題解答

@Override protected void onSaveInstanceState(Bundle outState) {//super.onSaveInstanceState(outState); }

這樣的解決辦法是不對的，這樣會導致從activity被銷毀是不能記住之前的顯示內容，從而使界面空白、為了解決fragment重疊，你可以在注釋掉super.onSaveInstanceState(outState)的同時，加上保存當前fragment的代碼

@Overrideprotected void onSaveInstanceState(Bundle outState) { outState.putString(SPConst.SHOW_TAG, showFragmentTag);}

然后在回來的時候重新獲取之前的fragment，然后再顯示出來

@Overrideprotected void onRestoreInstanceState(Bundle savedInstanceState) { super.onRestoreInstanceState(savedInstanceState); if (savedInstanceState != null) {showFragmentTag = savedInstanceState.getString(SPConst.SHOW_TAG);if (showFragmentTag != null) { showFragment = fragmentManager.findFragmentByTag(showFragmentTag); switch (showFragmentTag) {case fragmentTag1: workFragment = showFragment; break;case fragmentTag2: patientFragment = showFragment; break;case fragmentTag3: synergyFragment = showFragment; break;case fragmentTag4: toolFragment = showFragment; break;case fragmentTag5: mineFragment = showFragment; break; }} }}回答2：

內容有點亂，對于你這種需求，推薦使用FragmentTabHost,也就沒有這種亂七八糟的問題了。

直接用ViewPager就行