Java 导航抽屉onNavigationDrawerItemSelected在MainActivity onCreate之前调用?
我已经用导航抽屉片段的模板实现和MainActivity设置了一个新项目 它为我提供了以下相关方法:Java 导航抽屉onNavigationDrawerItemSelected在MainActivity onCreate之前调用?,java,android,android-intent,android-fragments,navigation-drawer,Java,Android,Android Intent,Android Fragments,Navigation Drawer,我已经用导航抽屉片段的模板实现和MainActivity设置了一个新项目 它为我提供了以下相关方法: @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Intent intent = getIntent(); token = intent
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Intent intent = getIntent();
token = intent.getStringExtra(EXTRA_TOKEN);
mNavigationDrawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
mNavigationDrawerFragment.activityMain = this;
mTitle = getTitle();
// Set up the drawer.
mNavigationDrawerFragment.setUp(
R.id.navigation_drawer,
(DrawerLayout) findViewById(R.id.drawer_layout));
}
My MainActivity由一个splash活动启动,该活动通过额外的\u令牌获取一个保存的访问令牌
这是对MainActivity中导航抽屉项select listener的覆盖:
@Override
public void onNavigationDrawerItemSelected(int position) {
// update the main content by replacing fragments
FragmentManager fragmentManager = getSupportFragmentManager();
onSectionAttached(position + 1);
switch(position) {
case 0:
fragmentManager.beginTransaction()
.replace(R.id.container, FeedFragment.newInstance(token, ""))
.commit();
break;
case 1:
fragmentManager.beginTransaction()
.replace(R.id.container, PeopleFragment.newInstance("", ""))
.commit();
break;
case 2:
if(qbloggedin) {
fragmentManager.beginTransaction()
.replace(R.id.container, MessagesFragment.newInstance(token, ""))
.commit();
}
break;
default:
break;
}
}
它根据在NavDrawer中选择的项目启动三个不同的片段。在实例化新片段时,标记
字符串被传递到其构造函数中,该构造函数保存在片段的类中以供进一步使用
然而,在应用程序的第一次启动时,似乎在onCreate
之前调用了onNavigationDrawerItemSelected
!这导致我将一个空值标记传递到片段中,导致它们都被弄乱了
这怎么可能?据我所知,NavigationDrawerFragment还不应该被设置
我在onCreate
和onNavigationDrawerItemSelected switch position=0上设置断点onNavigationDrawerItemSelected
确实在onCreate
之前命中
在尝试处理已选择的onNavigationDrawerItemSelected
之前,如何确保首先获取令牌
任何帮助都将不胜感激。您可以将意图移动到构造函数,并将您的令牌保存在那里,如下所示:
Intent i;
......
public FragmentConstructor() {
i = getIntent();
token = intent.getStringExtra(EXTRA_TOKEN);
}
我相信我发现了这一点,因为这是发生在我身上的任何人谁搜索这一点,并不能找到答案 如果您使用Android Studio DrawerActivity,那么他们会为您创建样板代码。在activity_main.xml或您的DrawerActivity设置为其内容视图的任何xml中的代码中,都有一个标记 在onCreate()中调用setContentView()时,会自动创建此片段,因此技术上仍会首先调用onCreate(),但随后会在create中调用onNavigationDrawerItemSelected()方法。由于setContentView通常保持在顶部,因此在尝试将片段的状态存储到抽屉中时会出现问题 只需将任何检查savedInstanceBundle的代码移到setContentView()上方,即可解决问题 带注释的示例:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// THIS IS WHERE YOU CHECK FOR SAVED INSTANCE
// Check for frag
if (savedInstanceState != null) {
Log.i(TAG, "Get QuestionDayFragment");
mQuestionDaysFragment = (QuestionDaysFragment) getSupportFragmentManager().getFragment(savedInstanceState, QUESTION_DAY_FRAGMENT);
}
// View injection
setContentView(R.layout.activity_main);
ButterKnife.inject(this);
// THIS IS WHERE THE CODE WAS BEFORE
// THIS WOULD BE CALLED AFTER onNavigationDrawerItemSelected()
// Singleton injection
LifeboxApplication.graph().inject(this);
// Toolbar
setSupportActionBar(mToolbar);
// FB
uiHelper = new UiLifecycleHelper(this, callback);
uiHelper.onCreate(savedInstanceState);
// Drawer
mNavigationDrawerFragment = (NavigationDrawerFragment) getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
mTitle = getTitle();
mNavigationDrawerFragment.setUp(R.id.navigation_drawer, (DrawerLayout) findViewById(R.id.drawer_layout));
}
我要做的是在执行onNavigationDrawerItemSelected之前检查页面是否已加载
private Boolean loaded=false;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Your code here
this.loaded=true;
}
public void onNavigationDrawerItemSelected(int position) {
if (!this.loaded){
return;
}
我还同意使用布尔值检查onCreate()是否已完成加载。我唯一的其他建议是,对于快速修复,您可以使用onSectionAttached(int number)来处理所选的每个项目,而不是onNavigationDrawerItemSelected 例如,当intent.method()具有上下文参数时,请提供帮助。当存在上下文参数时,intent.method(Context)将获得一个空上下文。