应用程序采用片段架构(单个MainActivity与导航抽屉,调用具体的片段)。
DayPagerFragment使用ViewPager与无限数量的页面(动态片段)。每一页代表一天。
DayPagerFragment:
public class DayPagerFragment extends Fragment {
private ViewPager mViewPager;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_day, container, false);
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
mViewPager = (ViewPager) view.findViewById(R.id.pager);
mViewPager.setOffscreenPageLimit(1);
mViewPager.setAdapter(new DayAdapter(getChildFragmentManager()));
}
private static class DayAdapter extends FragmentStatePagerAdapter {
public DayAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
return DayFragment.newInstance(null);
}
@Override
public int getCount() {
// I don't know the number to put here becauseI don't have
// a defined number of fragments (= dynamic fragments)
return 1;
}
@Override
public int getItemPosition(Object object){
return DayAdapter.POSITION_NONE;
}
}
public void setCurrentPagerItemPrev() {
//mViewPager.setCurrentItem(mViewPager.getCurrentItem() - 1);
mAdapterViewPager.getRegisteredFragment(mViewPager.getCurrentItem() - 1);
}
public void setCurrentPagerItemNext() {
//mViewPager.setCurrentItem(mViewPager.getCurrentItem() + 1);
mAdapterViewPager.getRegisteredFragment(mViewPager.getCurrentItem() + 1);
}
}
第一项优化:使用FragmentStatePagerAdapter
进行管理,因为FragmentPagerAdapter
不适用于我的用途/动态片段(将整个片段存储在内存中)。
第二项优化:我使用setOffscreenPageLimit(1)
设置了当前页面两侧应保留的页面数量。
DayFragment
public class DayFragment extends Fragment {
private TextView mDay;
private TextView mMonth;
private Button mPrevDay;
private Button mNextDay;
private ImageView mCenter;
private ImageView mLeft;
private ImageView mRight;
...
private DayRepository dayRepository;
private Day currentDay;
private Day prevDay;
private Day nextDay;
private DayUtil dayUtil;
private DayUtil dayUtilPrev;
private DayUtil dayUtilNext;
private Calendar cal;
private Calendar calPrev;
private Calendar calNext;
public static DayFragment newInstance(Calendar calendar) {
DayFragment dayFragment = new DayFragment();
Bundle args = new Bundle();
args.putInt("year", calendar.get(Calendar.YEAR));
args.putInt("month", calendar.get(Calendar.MONTH));
args.putInt("day", calendar.get(Calendar.DAY_OF_MONTH));
dayFragment.setArguments(args);
return dayFragment;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_day_nested, container, false);
mDay = (TextView) view.findViewById(R.id.textView_day);
mMonth = (TextView) view.findViewById(R.id.textView_month);
mCenter = (ImageView) view.findViewById(R.id.imageView_center); // Weather symbol (sun, cloud...) of D-Day
mLeft = (ImageView) view.findViewById(R.id.imageView_left); // Weather symbol of D-1
mRight = (ImageView) view.findViewById(R.id.imageView_right); // Weather symbol of D-2
//... get 6 others TextView/ImageView
MyApplication app = (MyApplication) getActivity().getApplicationContext();
// Get bundle args
int day = getArguments().getInt("day");
int month = getArguments().getInt("month");
int year = getArguments().getInt("year");
// Date
this.cal = new GregorianCalendar(year, month, day);
// Get prev/next day (for nav arrows)
this.calPrev = (GregorianCalendar) this.cal.clone();
this.calPrev.add(Calendar.DAY_OF_YEAR, -1);
this.calNext = (GregorianCalendar) this.cal.clone();
this.calNext.add(Calendar.DAY_OF_YEAR, 1);
// Get data from database
//...
// Utils
this.dayUtil = new DayUtil(currentDay, getActivity());
this.dayUtilPrev = new DayUtil(this.prevDay, getActivity());
this.dayUtilNext = new DayUtil(this.nextDay, getActivity());
String dateCurrentDayName = FormatUtil.getDayName(app.getLocale()).format(this.cal.getTime());
String dateCurrentDayNameCap = dateCurrentDayName.substring(0,1).toUpperCase() + dateCurrentDayName.substring(1);
String dateCurrentMonthName = FormatUtil.getMonthName(month, app.getLocale());
// Update UI
//... lot of setText(...) using day object and utils
mLeft.setImageResource(this.dayUtilPrev.getDrawable());
mCenter.setImageResource(dayUtil.getDrawable());
mRight.setImageResource(this.dayUtilNext.getDrawable());
return view;
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
// Custom fonts
MyApplication app = (MyApplication) getActivity().getApplication();
ViewGroup vg = (ViewGroup)getActivity().getWindow().getDecorView();
ViewUtil.setTypeFace(app.getTrebuchet(), vg);
// Navigation between days
mMoonPrevDay.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
((MainActivity)getActivity()).viewDay(calPrev);
}
});
mMoonNextDay.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
((MainActivity) getActivity()).viewDay(calNext);
}
});
}
// Never called!
@Override
public void onDestroy() {
super.onDestroy();
Log.w("com.example", "Fragment day destroyed");
}
}
问题:
我的应用非常图形化,因为每个页面都显示:
- 10个文本框(内部文本根据日期变化)
- 4个ImageView(D-1、D-Day、D+1的天气符号)+ 另一个ImageView
当我浏览ViewPager页面时,很快就会出现OutOfMemoryError(大约在30页后)。
就像Fragment没有从内存中被释放一样。垃圾回收器并不像我期望的那样工作(我认为是因为某些内容引用了旧的片段)。
Logcat
04-06 20:01:21.683 27008-27008/com.example D/dalvikvm﹕ GC_BEFORE_OOM freed 348K, 2% free 194444K/196608K, paused 93ms, total 93ms
04-06 20:01:21.683 27008-27008/com.example E/dalvikvm-heap﹕ Out of memory on a 1790260-byte allocation.
04-06 20:01:21.693 27008-27008/com.example E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example, PID: 27008
java.lang.OutOfMemoryError
at android.graphics.BitmapFactory.nativeDecodeAsset(Native Method)
at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:587)
at android.graphics.BitmapFactory.decodeResourceStream(BitmapFactory.java:422)
at android.graphics.drawable.Drawable.createFromResourceStream(Drawable.java:840)
at android.content.res.Resources.loadDrawable(Resources.java:2110)
at android.content.res.Resources.getDrawable(Resources.java:700)
at android.widget.ImageView.resolveUri(ImageView.java:638)
at android.widget.ImageView.setImageResource(ImageView.java:367)
at com.example.ui.DayFragment.onCreateView(DayFragment.java:126) //...mLeft.setImageResource()
at android.support.v4.app.Fragment.performCreateView(Fragment.java:1500)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:927)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1467)
at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:440)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
04-06 20:01:21.773 27008-27008/com.example I/dalvikvm-heap﹕ Clamp target GC heap from 197.480MB to 192.000MB
04-06 20:01:21.773 27008-27008/com.example D/dalvikvm﹕ GC_FOR_ALLOC freed 565K, 2% free 193932K/196608K, paused 73ms, total 73ms
我有一个内存泄漏问题,但不知道出在哪里和为什么。我尝试使用Eclipse MAT (Memory Analyser),但是还是找不到问题所在。
你能帮我吗?
编辑: 为了加载字体,我使用了以下代码: DayFragment.java
// Custom fonts
MyApplication app = (MyApplication) getActivity().getApplication();
ViewGroup vg = (ViewGroup)getActivity().getWindow().getDecorView();
ViewUtil.setTypeFace(app.getTrebuchet(), vg);
MyApplication.java
public Typeface getTrebuchet() {
if (trebuchet == null){
trebuchet = Typeface.createFromAsset(getAssets(), Consts.PATH_TYPEFACE_TREBUCHET);
}
return trebuchet;
}
我的DDMS显示了内存泄漏:
编辑2:重要提示!
我的应用程序中使用了导航抽屉,由唯一的活动MainActivity
处理。导航抽屉使用碎片(而不是活动)。
这就是为什么DayPagerFragment
扩展自Fragment
(而不是FragmentActivity
或Activity
)。
为了在日期之间进行滑动,用户必须触摸两个按钮(prev / next)。我在DayFragment
上使用setOnClickListener
来处理这些按钮(请参见我的更新代码)。
问题是我调用了((MainActivity)getActivity()).viewDay(calPrev);
MainActivity
public class MainActivity extends ActionBarActivity implements NavigationDrawerFragment.NavigationDrawerCallbacks {
private NavigationDrawerFragment mNavigationDrawerFragment;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
...
// Set up the navigation drawer
mNavigationDrawerFragment.setUp(R.id.navigation_drawer, (DrawerLayout) findViewById(R.id.drawer_layout));
}
...
public void viewDay(Calendar calendar) {
DayFragment dayFragment = DayFragment.newInstance(calendar); // The problem is here I think !
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction()
.setCustomAnimations(android.R.anim.fade_in, android.R.anim.fade_out)
.replace(R.id.container, dayFragment)
.addToBackStack(null)
.commit();
}
}
所以...我认为因为我每次实例化一个新的fragment,ViewPager
就不能发挥它的作用!而且MainActivity
保留了对每个Fragment的引用:这就是为什么垃圾回收器不释放内存的原因。
现在:
- 我不知道我的理论是否正确
- 如何更正?如何从
setOnClickListener
调用setCurrentPagerItemPrev
和setCurrentPagerItemNext
方法(请查看我在DayPagerFragment
中的更新代码)?
NB: 我使用mAdapterViewPager.getRegisteredFragment()
代替mViewPager.setCurrentItem
,因为我的DayAdapter
扩展自SmartFragmentStatePagerAdapter
,但它们是相同的。