如何使用Dagger2将FragmentPagerAdapter正确地插入我的活动类中？
Posted
tags:
篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了如何使用Dagger2将FragmentPagerAdapter正确地插入我的活动类中？相关的知识，希望对你有一定的参考价值。
我正在尝试制作一个提供ViewPagerAdapter的模块类AdaptersModules。 ViewPagerAdapter是扩展FragmentPagerAdapter的类。 ViewPagerAdapter构造函数需要FragmentManager。
我的活动分类是：
public class TabsActivity extends AppCompatActivity
public FragmentManager fm = getSupportFragmentManager();
@Inject ViewPagerAdapter adapter;
@Inject HomeFragment homeFragment;
@Inject ChallengeFragment challengeFragment;
@Inject FriendsFragment friendsFragment;
@Inject OptionsFragment optionsFragment;
@Inject QuickPhotoFragment quickPhotoFragment;
@Inject TrophiesFragment trophiesFragment;
@BindView(R.id.toolbar) Toolbar toolbar;
@BindView(R.id.tabsTabLayout) TabLayout tabLayout;
@BindView(R.id.tabsViewPager) ViewPager viewPager;
private int[] tabIcons = R.drawable.ic_home,
R.drawable.ic_quick_photo,
R.drawable.ic_challenge,
R.drawable.ic_friends,
R.drawable.ic_trophies,
R.drawable.ic_settings ;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_tabs);
ButterKnife.bind(this);
((MeetBamApplication)getApplication())
.getComponent()
.inject(this);
setSupportActionBar(toolbar);
getSupportActionBar().setDefaultDisplayHomeAsUpEnabled(true);
setupViewPager(viewPager);
tabLayout.setupWithViewPager(viewPager);
for (int i=0; i<viewPager.getAdapter().getCount(); i++)
tabLayout.getTabAt(i).setIcon(tabIcons[i]);
private void setupViewPager(ViewPager viewPager)
adapter.addFragment(homeFragment);
adapter.addFragment(quickPhotoFragment);
adapter.addFragment(challengeFragment);
adapter.addFragment(friendsFragment);
adapter.addFragment(trophiesFragment);
adapter.addFragment(optionsFragment);
viewPager.setAdapter(adapter);
我的模块类别：
@Module
public class AdaptersModules extends TabsActivity
@Singleton
@Provides
protected ViewPagerAdapter provideViewPagerAdapter()
return new ViewPagerAdapter(fm);
和组件：
@Singleton
@Component(modules =
AppModule.class,
TabsModules.class,
AdaptersModules.class)
public interface ApplicationComponent
void inject(MeetBamApplication meetBamApplication);
void inject(TabsActivity activity);
ViewPagerAdapter类是：
public class ViewPagerAdapter extends FragmentPagerAdapter
private final List<Fragment> mFragmentList = new ArrayList<>();
public void addFragment(Fragment fragment) mFragmentList.add(fragment);
public ViewPagerAdapter(FragmentManager fm) super(fm);
@Override
public Fragment getItem(int position) return mFragmentList.get(position);
@Override
public int getCount() return mFragmentList.size();
当我运行并测试应用程序时，我得到：
FATAL EXCEPTION: main
Process: com.thomsoncompany.meetbamgo, PID: 23733
java.lang.IllegalStateException: Activity has been destroyed
at android.support.v4.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1515)
at android.support.v4.app.BackStackRecord.commitInternal(BackStackRecord.java:638)
at android.support.v4.app.BackStackRecord.commitAllowingStateLoss(BackStackRecord.java:621)
at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:139)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1177)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1025)
at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1545)
at android.view.View.measure(View.java:17782)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5625)
at android.support.design.widget.CoordinatorLayout.onMeasureChild(CoordinatorLayout.java:668)
at android.support.design.widget.CoordinatorLayout.onMeasure(CoordinatorLayout.java:735)
at android.view.View.measure(View.java:17782)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5625)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:459)
at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:135)
at android.view.View.measure(View.java:17782)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5625)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1692)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:760)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:629)
at android.view.View.measure(View.java:17782)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5625)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:459)
at android.view.View.measure(View.java:17782)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5625)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1692)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:760)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:629)
at android.view.View.measure(View.java:17782)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5625)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:459)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2644)
at android.view.View.measure(View.java:17782)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2389)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1399)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1623)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1277)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6483)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:802)
at android.view.Choreographer.doCallbacks(Choreographer.java:605)
at android.view.Choreographer.doFrame(Choreographer.java:574)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:788)
at android.os.Handler.handleCallback(Handler.java:815)
at android.os.Handler.dispatchMessage(Handler.java:104)
at android.os.Looper.loop(Looper.java:194)
at android.app.ActivityThread.main(ActivityThread.java:5549)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:964)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:759)
我该怎么办？
答案
[当您在Android中使用Dagger 2时，需要非常小心以确保您注入的成员正确跟踪注入目标的lifecycles。
ViewPagerAdapter取决于FragmentManager。 FragmentManager是应用程序单例。 FragmentManager之后的某个时间，单个FragmentManager将对Activity可用，并将仅遵循该Activity的生命周期。换句话说，当该活动被销毁时，onCreate()不可用。如果以后通过将其设为单例来保留对它的引用，则将发生内存泄漏和上述错误，因为与其关联的活动将不再存在。处理此问题的正确方法是制作一个新组件来跟踪您的Activity的生命周期：
FragmentManager
然后为您的活动创建一个模块，该模块可以提供需要跟踪该活动的生命周期的成员：
@PerActivity
@Component( dependencies = ApplicationComponent.class , modules = TabsModule.class, AdaptersModule.class, TabActivityModule.class
public interface TabComponent
void inject(TabsActivtiy activity);
以上是关于如何使用Dagger2将FragmentPagerAdapter正确地插入我的活动类中？的主要内容，如果未能解决你的问题，请参考以下文章