1,问题:
应用长期在后台的场景下,进入前台时,fragment显示为空白
2,app框架大体实现:
1个activity+多个Fragment,使用的是add()方法以及 hide(),show()方法,显示fragment
3,相关代码:
onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // 判断 savedInstanceState是否为空: setCanResizeWindow(false); maskView = new View(getApplicationContext()); maskView.setBackground(new ColorDrawable(Color.parseColor("#30000000"))); maskView.setClickable(true); maskView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { removeMask(); } }); setContentView(R.layout.activity_home); EventBus.getDefault().register(this); //3,个推 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); //第一次登录系统时,修改数据库的Istravelrely字段 if (!SpUtils.getSynDB(getApplicationContext())) { ThreadPoolUtil.getmExecutor().execute(new Runnable() { @Override public void run() { CopyLocalContactsUtils.checkIsTravelRely(getApplication()); SpUtils.setSynDB(getApplicationContext()); } }); } //初始化mBottomDial为选中状态,fl_content填充DialFragment mBottomDial.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(); }
尝试过的解决办法:
1,为了解决多个fragment重叠显示,在activity的中执行了如下:
@Override protected void onSaveInstanceState(Bundle outState) { // super.onSaveInstanceState(outState); }
问题现象:
直接用ViewPager就行
内容有点乱,对于你这种需求,推荐使用FragmentTabHost
,也就没有这种乱七八糟的问题了。
@Override protected void onSaveInstanceState(Bundle outState) { // super.onSaveInstanceState(outState); }
这样的解决办法是不对的,这样会导致从activity被销毁是不能记住之前的显示内容,从而使界面空白、
为了解决fragment重叠,你可以在注释掉super.onSaveInstanceState(outState)的同时,加上保存当前fragment的代码
@Override protected void onSaveInstanceState(Bundle outState) { outState.putString(SPConst.SHOW_TAG, showFragmentTag); }
然后在回来的时候重新获取之前的fragment,然后再显示出来
@Override protected 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; } } } }