Fragment的生命周期我们都不陌生，但是其如何利用FragmentManager从Activity生命周期挂载而来的呢,尤其是看了glide源码后，发现其巧妙的利用了FragmentManager来绑定自己的生命周期，那么为了更清晰的深入理解，一起来看下6.0的源码是如何处理的。
FragmentActivity
- 1.从启动一个FragmentActivity开始。从onCreate()方法中
final FragmentController mFragments = FragmentController.createController(new HostCallbacks());
@SuppressWarnings("deprecation")
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
mFragments.attachHost(null /*parent*/);
super.onCreate(savedInstanceState);
NonConfigurationInstances nc =
(NonConfigurationInstances) getLastNonConfigurationInstance();
if (nc != null) {
mFragments.restoreLoaderNonConfig(nc.loaders);
}
if (savedInstanceState != null) {
Parcelable p = savedInstanceState.getParcelable(FRAGMENTS_TAG);
mFragments.restoreAllState(p, nc != null ? nc.fragments : null);
}
mFragments.dispatchCreate();
}- 1.1 重点关注一下 mFragments 的操作。当前的mFragments其实是FragmentController，而FragmentHostCallback在FragmentController初始化时进行初始化，在FragmentHostCallback中可以拿到FragmentManager的子类FragmentManagerImpl。继续看FragmentController的代码
//FragmentController初始化CallBack
public static final FragmentController createController(FragmentHostCallback<?> callbacks) {
return new FragmentController(callbacks);
}
private FragmentController(FragmentHostCallback<?> callbacks) {
mHost = callbacks;
}
public void attachHost(Fragment parent) {
mHost.mFragmentManager.attachController(
mHost, mHost /*container*/, parent);
}
public void restoreAllState(Parcelable state, FragmentManagerNonConfig nonConfig) {
mHost.mFragmentManager.restoreAllState(state, nonConfig);
}
public void dispatchCreate() {
mHost.mFragmentManager.dispatchCreate();
}- 1.2当前的操作其实都是对FragmentManager进行操作，继续看FragmentManagerImpl代码
// 初始化赋值操作
public void attachController(FragmentHostCallback host,
FragmentContainer container, Fragment parent) {
if (mHost != null) throw new IllegalStateException("Already attached");
mHost = host;
mContainer = container;
mParent = parent;
}
void restoreAllState(Parcelable state, FragmentManagerNonConfig nonConfig) {
......
if (nonConfig != null) {
List<Fragment> nonConfigFragments = nonConfig.getFragments();
childNonConfigs = nonConfig.getChildNonConfigs();
final int count = nonConfigFragments != null ? nonConfigFragments.size() : 0;
for (int i = 0; i < count; i++) {
Fragment f = nonConfigFragments.get(i);
if (DEBUG) Log.v(TAG, "restoreAllState: re-attaching retained " + f);
FragmentState fs = fms.mActive[f.mIndex];
fs.mInstance = f;
f.mSavedViewState = null;
f.mBackStackNesting = 0;
f.mInLayout = false;
f.mAdded = false;
f.mTarget = null;
if (fs.mSavedFragmentState != null) {
fs.mSavedFragmentState.setClassLoader(mHost.getContext().getClassLoader());
f.mSavedViewState = fs.mSavedFragmentState.getSparseParcelableArray(
FragmentManagerImpl.VIEW_STATE_TAG);
f.mSavedFragmentState = fs.mSavedFragmentState;
}
}
}
// Build the full list of active fragments, instantiating them from
// their saved state.
mActive = new ArrayList<>(fms.mActive.length);
// 注意，后面会用到
...
}
public void dispatchCreate() {
mStateSaved = false;
mExecutingActions = true;
moveToState(Fragment.CREATED, false);
mExecutingActions = false;
}
- 1.3 以上，attachController() 只是简单的初始化的赋值操作，并无对生命周期相关的，继续看restoreAllState(),同样的初始化的重置操作,这里
mActive = new ArrayList(fms.mActive.length)初始化了一个空的mActive的list。继续看dispatchCreate()，其中moveToState
void moveToState(int newState, boolean always) {
if (mHost == null && newState != Fragment.INITIALIZING) {
throw new IllegalStateException("No activity");
}
if (!always && newState == mCurState) {
return;
}
mCurState = newState;
if (mActive != null) {
boolean loadersRunning = false;
// Must add them in the proper order. mActive fragments may be out of order
if (mAdded != null) {
final int numAdded = mAdded.size();
for (int i = 0; i < numAdded; i++) {
Fragment f = mAdded.get(i);
moveFragmentToExpectedState(f);
if (f.mLoaderManager != null) {
loadersRunning |= f.mLoaderManager.hasRunningLoaders();
}
}
}
// Now iterate through all active fragments. These will include those that are removed
// and detached.
final int numActive = mActive.size();
for (int i = 0; i < numActive; i++) {
Fragment f = mActive.get(i);
if (f != null && (f.mRemoving || f.mDetached) && !f.mIsNewlyAdded) {
moveFragmentToExpectedState(f);
if (f.mLoaderManager != null) {
loadersRunning |= f.mLoaderManager.hasRunningLoaders();
}
}
}
if (!loadersRunning) {
startPendingDeferredFragments();
}
if (mNeedMenuInvalidate && mHost != null && mCurState == Fragment.RESUMED) {
mHost.onSupportInvalidateOptionsMenu();
mNeedMenuInvalidate = false;
}
}
}1.4 moveToState() 其实是更新FragmentManager的状态至Fragment，但是当前并无Fragment,mActive在restoreAllState()初始化出来后只是个空的list，因此并没有实质的操作。至此FragmentActivity onCreate()都是初始化的操作。
2 Fragment的真正启动是当我们调用FragmentManager.beginTransaction().add(fragmet).commit()时触发。看下代码
public abstract class FragmentTransaction {
......
public abstract int commit();
/**
* Calls {@link #add(int, Fragment, String)} with a 0 containerViewId.
*/
public abstract FragmentTransaction add(Fragment fragment, String tag);
/**
* Calls {@link #add(int, Fragment, String)} with a null tag.
*/
public abstract FragmentTransaction add(@IdRes int containerViewId, Fragment fragment);
public abstract FragmentTransaction add(@IdRes int containerViewId, Fragment fragment,
@Nullable String tag);
......
}- 2.1 抽象类FragmentTransaction，这里有个add(Fragment fragment, String tag)方法，添加一个Fragment，只设置tag,不设置viewId,说白了添加一个不妨碍业务的空Fragment方法，这是glide的绑定生命周期的一个点。继续看实现类
final class BackStackRecord extends FragmentTransaction implements
FragmentManager.BackStackEntry, Runnable {
...
public FragmentTransaction add(int containerViewId, Fragment fragment) {
doAddOp(containerViewId, fragment, null, OP_ADD);
return this;
}
private void doAddOp(int containerViewId, Fragment fragment, String tag, int opcmd) {
fragment.mFragmentManager = mManager;
if (tag != null) {
if (fragment.mTag != null && !tag.equals(fragment.mTag)) {
throw new IllegalStateException("Can't change tag of fragment "
+ fragment + ": was " + fragment.mTag
+ " now " + tag);
}
fragment.mTag = tag;
}
if (containerViewId != 0) {
if (fragment.mFragmentId != 0 && fragment.mFragmentId != containerViewId) {
throw new IllegalStateException("Can't change container ID of fragment "
+ fragment + ": was " + fragment.mFragmentId
+ " now " + containerViewId);
}
fragment.mContainerId = fragment.mFragmentId = containerViewId;
}
Op op = new Op();
op.cmd = opcmd;
op.fragment = fragment;
addOp(op);
}
void addOp(Op op) {
if (mHead == null) {
mHead = mTail = op;
} else {
op.prev = mTail;
mTail.next = op;
mTail = op;
}
op.enterAnim = mEnterAnim;
op.exitAnim = mExitAnim;
op.popEnterAnim = mPopEnterAnim;
op.popExitAnim = mPopExitAnim;
mNumOp++;
}
public int commit() {
return commitInternal(false);
}
int commitInternal(boolean allowStateLoss) {
if (mCommitted) throw new IllegalStateException("commit already called");
if (FragmentManagerImpl.DEBUG) {
Log.v(TAG, "Commit: " + this);
LogWriter logw = new LogWriter(TAG);
PrintWriter pw = new PrintWriter(logw);
dump(" ", null, pw, null);
}
mCommitted = true;
if (mAddToBackStack) {
mIndex = mManager.allocBackStackIndex(this);
} else {
mIndex = -1;
}
mManager.enqueueAction(this, allowStateLoss);
return mIndex;
}
...
}- 2.2 先看add(),在实现类中调用到了doAddOp(),而在doAddOp方法内去对当前的Fragment进栈操作,这里OP_ADD为op.cmd = opcmd;的赋值，对应的操作如下，mManager.addFragment(f, false)很明显添加一个Fragment。并break;
public void run() {
...
while (op != null) {
int enterAnim = state != null ? 0 : op.enterAnim;
int exitAnim = state != null ? 0 : op.exitAnim;
switch (op.cmd) {
case OP_ADD: {
Fragment f = op.fragment;
f.mNextAnim = enterAnim;
mManager.addFragment(f, false);
} break;
case OP_REPLACE: {
...
if (f != null) {
f.mNextAnim = enterAnim;
mManager.addFragment(f, false);
}
} break;
case OP_REMOVE: {
Fragment f = op.fragment;
f.mNextAnim = exitAnim;
mManager.removeFragment(f, transition, transitionStyle);
} break;
case OP_HIDE: {
Fragment f = op.fragment;
f.mNextAnim = exitAnim;
mManager.hideFragment(f, transition, transitionStyle);
} break;
case OP_SHOW: {
Fragment f = op.fragment;
f.mNextAnim = enterAnim;
mManager.showFragment(f, transition, transitionStyle);
} break;
case OP_DETACH: {
Fragment f = op.fragment;
f.mNextAnim = exitAnim;
mManager.detachFragment(f, transition, transitionStyle);
} break;
case OP_ATTACH: {
Fragment f = op.fragment;
f.mNextAnim = enterAnim;
mManager.attachFragment(f, transition, transitionStyle);
} break;
default: {
throw new IllegalArgumentException("Unknown cmd: " + op.cmd);
}
}
op = op.next;
}
mManager.moveToState(mManager.mCurState, transition, transitionStyle, true);
...
}
public void addFragment(Fragment fragment, boolean moveToStateNow) {
if (mAdded == null) {
mAdded = new ArrayList<Fragment>();
}
if (DEBUG) Log.v(TAG, "add: " + fragment);
makeActive(fragment);
if (!fragment.mDetached) {
if (mAdded.contains(fragment)) {
throw new IllegalStateException("Fragment already added: " + fragment);
}
mAdded.add(fragment);
fragment.mAdded = true;
fragment.mRemoving = false;
if (fragment.mHasMenu && fragment.mMenuVisible) {
mNeedMenuInvalidate = true;
}
if (moveToStateNow) {
moveToState(fragment);
}
}
}- 2.3 最后肯定是走到moveToState(fragment)；moveToState(fragment)这个方法很重要，break后走这里，这个方法一会继续看，我们顺带看一下其他的commit()操作。当前BackStackRecord实现类中的mManager是FragmentManagerImpl。这就很好理解了，又转到了熟悉的FragmentManagerImpl中了，继续看代码。
mManager.enqueueAction(this, allowStateLoss);
final class FragmentManagerImpl extends FragmentManager implements LayoutInflaterFactory {
/**
* Adds an action to the queue of pending actions.
*
* @param action the action to add
* @param allowStateLoss whether to allow loss of state information
* @throws IllegalStateException if the activity has been destroyed
*/
public void enqueueAction(Runnable action, boolean allowStateLoss) {
if (!allowStateLoss) {
checkStateLoss();
}
synchronized (this) {
if (mDestroyed || mHost == null) {
throw new IllegalStateException("Activity has been destroyed");
}
if (mPendingActions == null) {
mPendingActions = new ArrayList<Runnable>();
}
mPendingActions.add(action);
if (mPendingActions.size() == 1) {
mHost.getHandler().removeCallbacks(mExecCommit);
mHost.getHandler().post(mExecCommit);
}
}
}
Runnable mExecCommit = new Runnable() {
@Override
public void run() {
execPendingActions();
}
};
}- 2.4 在 mPendingActions.add(action)中，mPendingActions为action的list，添加一个事件，如果是第一个，发送消息mHost.getHandler().post(mExecCommit)，继续看mExecCommit消息就走到了execPendingActions(),上代码看下
/**
* Only call from main thread!
*/
public boolean execPendingActions() {
if (mExecutingActions) {
throw new IllegalStateException("Recursive entry to executePendingTransactions");
}
if (Looper.myLooper() != mHost.getHandler().getLooper()) {
throw new IllegalStateException("Must be called from main thread of process");
}
boolean didSomething = false;
while (true) {
int numActions;
synchronized (this) {
if (mPendingActions == null || mPendingActions.size() == 0) {
break;
}
numActions = mPendingActions.size();
if (mTmpActions == null || mTmpActions.length < numActions) {
mTmpActions = new Runnable[numActions];
}
mPendingActions.toArray(mTmpActions);
mPendingActions.clear();
mHost.getHandler().removeCallbacks(mExecCommit);
}
mExecutingActions = true;
for (int i=0; i<numActions; i++) {
mTmpActions[i].run();
mTmpActions[i] = null;
}
mExecutingActions = false;
didSomething = true;
}
if (mHavePendingDeferredStart) {
boolean loadersRunning = false;
for (int i=0; i<mActive.size(); i++) {
Fragment f = mActive.get(i);
if (f != null && f.mLoaderManager != null) {
loadersRunning |= f.mLoaderManager.hasRunningLoaders();
}
}
if (!loadersRunning) {
mHavePendingDeferredStart = false;
startPendingDeferredFragments();
}
}
return didSomething;
}
- 2.5 这里关注startPendingDeferredFragments()就可以了
void startPendingDeferredFragments() {
if (mActive == null) return;
for (int i=0; i<mActive.size(); i++) {
Fragment f = mActive.get(i);
if (f != null) {
performPendingDeferredStart(f);
}
}
}
public void performPendingDeferredStart(Fragment f) {
if (f.mDeferStart) {
if (mExecutingActions) {
// Wait until we're done executing our pending transactions
mHavePendingDeferredStart = true;
return;
}
f.mDeferStart = false;
moveToState(f, mCurState, 0, 0, false);
}
}- 2.6 重点来了，最后我们可以看到ragmentManager.beginTransaction().add(fragmet).commit()的操作，commit最终调用到了moveToState()。也走到了这里
void moveToState(Fragment f, int newState, int transit, int transitionStyle,
boolean keepActive) {
if (f.mState < newState) {
switch (f.mState) {
case Fragment.INITIALIZING:
...
f.mHost = mHost;
f.mParentFragment = mParent;
f.mFragmentManager = mParent != null
? mParent.mChildFragmentManager :mHost.getFragmentManagerImpl();
f.mCalled = false;
f.onAttach(mHost.getContext());
if (f.mParentFragment == null) {
mHost.onAttachFragment(f);
}
if (!f.mRetaining) { f.performCreate(f.mSavedFragmentState);
}
f.mRetaining = false;
if (f.mFromLayout) {
// For fragments that are part of the content view
// layout, we need to instantiate the view immediately
// and the inflater will take care of adding it.
f.mView = f.performCreateView(f.getLayoutInflater(
f.mSavedFragmentState), null,f.mSavedFragmentState);
if (f.mView != null) {
f.mInnerView = f.mView;
if (f.mHidden) f.mView.setVisibility(View.GONE);
f.onViewCreated(f.mView, f.mSavedFragmentState);
...
}
}
case Fragment.CREATED:
if (newState > Fragment.CREATED) {
if (DEBUG) Log.v(TAG, "moveto ACTIVITY_CREATED: " + f);
if (!f.mFromLayout) {
ViewGroup container = null;
if (f.mContainerId != 0) {
container = (ViewGroup)mContainer.onFindViewById(f.mContainerId);
}
f.mContainer = container;
f.mView = f.performCreateView(f.getLayoutInflater(
f.mSavedFragmentState), container, f.mSavedFragmentState);
if (f.mView != null) {
f.mInnerView = f.mView;
if (Build.VERSION.SDK_INT >= 11) {
ViewCompat.setSaveFromParentEnabled(f.mView, false);
} else {
f.mView = NoSaveStateFrameLayout.wrap(f.mView);
}
if (container != null) {
Animation anim = loadAnimation(f, transit, true,
transitionStyle);
if (anim != null) {
setHWLayerAnimListenerIfAlpha(f.mView, anim);
f.mView.startAnimation(anim);
}
container.addView(f.mView);
}
if (f.mHidden) f.mView.setVisibility(View.GONE);
f.onViewCreated(f.mView, f.mSavedFragmentState);
} else {
f.mInnerView = null;
}
}
f.performActivityCreated(f.mSavedFragmentState);
if (f.mView != null) {
f.restoreViewState(f.mSavedFragmentState);
}
f.mSavedFragmentState = null;
}
case Fragment.ACTIVITY_CREATED:
case Fragment.STOPPED:
if (newState > Fragment.STOPPED) {
if (DEBUG) Log.v(TAG, "moveto STARTED: " + f);
f.performStart();
}
case Fragment.STARTED:
if (newState > Fragment.STARTED) {
if (DEBUG) Log.v(TAG, "moveto RESUMED: " + f);
f.mResumed = true;
f.performResume();
f.mSavedFragmentState = null;
f.mSavedViewState = null;
}
}
} else if (f.mState > newState) {
switch (f.mState) {
case Fragment.RESUMED:
if (newState < Fragment.RESUMED) {
if (DEBUG) Log.v(TAG, "movefrom RESUMED: " + f);
f.performPause();
f.mResumed = false;
}
case Fragment.STARTED:
if (newState < Fragment.STARTED) {
if (DEBUG) Log.v(TAG, "movefrom STARTED: " + f);
f.performStop();
}
case Fragment.STOPPED:
if (newState < Fragment.STOPPED) {
if (DEBUG) Log.v(TAG, "movefrom STOPPED: " + f);
f.performReallyStop();
}
case Fragment.ACTIVITY_CREATED:
if (newState < Fragment.ACTIVITY_CREATED) {
if (DEBUG) Log.v(TAG, "movefrom ACTIVITY_CREATED: " + f);
if (f.mView != null) {
// Need to save the current view state if not
// done already.
if (mHost.onShouldSaveFragmentState(f) && f.mSavedViewState == null) {
saveFragmentViewState(f);
}
}
f.performDestroyView();
if (f.mView != null && f.mContainer != null) {
Animation anim = null;
if (mCurState > Fragment.INITIALIZING && !mDestroyed) {
anim = loadAnimation(f, transit, false,
transitionStyle);
}
if (anim != null) {
final Fragment fragment = f;
f.mAnimatingAway = f.mView;
f.mStateAfterAnimating = newState;
final View viewToAnimate = f.mView;
anim.setAnimationListener(new AnimateOnHWLayerIfNeededListener(
viewToAnimate, anim) {
@Override
public void onAnimationEnd(Animation animation) {
super.onAnimationEnd(animation);
if (fragment.mAnimatingAway != null) {
fragment.mAnimatingAway = null;
moveToState(fragment, fragment.mStateAfterAnimating,
0, 0, false);
}
}
});
f.mView.startAnimation(anim);
}
f.mContainer.removeView(f.mView);
}
f.mContainer = null;
f.mView = null;
f.mInnerView = null;
}
case Fragment.CREATED:
if (newState < Fragment.CREATED) {
if (mDestroyed) {
if (f.mAnimatingAway != null) {
// The fragment's containing activity is
// being destroyed, but this fragment is
// currently animating away. Stop the
// animation right now -- it is not needed,
// and we can't wait any more on destroying
// the fragment.
View v = f.mAnimatingAway;
f.mAnimatingAway = null;
v.clearAnimation();
}
}
if (f.mAnimatingAway != null) {
// We are waiting for the fragment's view to finish
// animating away. Just make a note of the state
// the fragment now should move to once the animation
// is done.
f.mStateAfterAnimating = newState;
newState = Fragment.CREATED;
} else {
if (DEBUG) Log.v(TAG, "movefrom CREATED: " + f);
if (!f.mRetaining) {
f.performDestroy();
}
f.mCalled = false;
f.onDetach();
if (!f.mCalled) {
throw new SuperNotCalledException("Fragment " + f
+ " did not call through to super.onDetach()");
}
if (!keepActive) {
if (!f.mRetaining) {
makeInactive(f);
} else {
f.mHost = null;
f.mParentFragment = null;
f.mFragmentManager = null;
f.mChildFragmentManager = null;
}
}
}
}
} - 3.moveToState()代码有点多，精简一下
void moveToState(Fragment f, int newState, int transit, int transitionStyle,
boolean keepActive) {
if ((!f.mAdded || f.mDetached) && newState > Fragment.CREATED) {
newState = Fragment.CREATED;
}
if (f.mRemoving && newState > f.mState) {
newState = f.mState;
}
if (f.mDeferStart && f.mState < Fragment.STARTED && newState > Fragment.STOPPED) {
newState = Fragment.STOPPED;
}
if (f.mState < newState) {
switch (f.mState) {
case Fragment.INITIALIZING:
f.onAttach(mHost.getContext());
mHost.onAttachFragment(f);
f.onViewCreated(f.mView, f.mSavedFragmentState);
case Fragment.CREATED:
container.addView(f.mView);
f.onViewCreated(f.mView, f.mSavedFragmentState);
f.performActivityCreated(f.mSavedFragmentState);
f.restoreViewState(f.mSavedFragmentState);
case Fragment.ACTIVITY_CREATED:
case Fragment.STOPPED:
f.performStart();
case Fragment.STARTED:
f.performResume();
}
} else if (f.mState > newState) {
switch (f.mState) {
case Fragment.RESUMED:
if (newState < Fragment.RESUMED) {
f.performPause();
}
case Fragment.STARTED:
if (newState < Fragment.STARTED) {
f.performStop();
}
case Fragment.STOPPED:
if (newState < Fragment.STOPPED) {
f.performReallyStop();
}
case Fragment.ACTIVITY_CREATED:
if (newState < Fragment.ACTIVITY_CREATED) {
f.performDestroyView();
}
case Fragment.CREATED:
if (newState < Fragment.CREATED) {
if (f.mAnimatingAway != null) {
newState = Fragment.CREATED;
} else {
f.performDestroy();
f.mCalled = false;
f.onDetach();
}
}
}
}
}public class Fragment implements ComponentCallbacks, OnCreateContextMenuListener {
static final int INITIALIZING = 0; // Not yet created.
static final int CREATED = 1; // Created.
static final int ACTIVITY_CREATED = 2; // The activity has finished its creation.
static final int STOPPED = 3; // Fully created, not started.
static final int STARTED = 4; // Created and started, not resumed.
static final int RESUMED = 5; // Created started and resumed.
}3.1 当前switch的各个case并没有break;这里有个
mCurState = newState;对mCurState的赋值操作
当FragmentActivity启动后，newState已经是Fragment.RESUMED了。所以现在是f.mState = Fragment.INITIALIZING，newState = RESUMED；根据switch中的case依次走了Fragment的创建的生命周期。4 销毁过程同理了，还是在moveToState()。依次来看
- 4.1 getFragmentManager().beginTransaction().remove(fragment()).commit();
FragmentTransaction{
public abstract FragmentTransaction remove(Fragment var1)
}
BackStackRecord{
public FragmentTransaction remove(Fragment fragment) {
Op op = new Op();
op.cmd = OP_REMOVE;
op.fragment = fragment;
addOp(op);
return this;
}
}
- 4.2 这里op.cmd = OP_REMOVE下面会用到，还是开始的run()内，可以看到add()也是在这里进行操作。remove也一样:mManager.removeFragment();
public void run() {
...
while (op != null) {
int enterAnim = state != null ? 0 : op.enterAnim;
int exitAnim = state != null ? 0 : op.exitAnim;
switch (op.cmd) {
case OP_ADD: {
Fragment f = op.fragment;
f.mNextAnim = enterAnim;
mManager.addFragment(f, false);
} break;
case OP_REPLACE: {
...
if (f != null) {
f.mNextAnim = enterAnim;
mManager.addFragment(f, false);
}
} break;
case OP_REMOVE: {
Fragment f = op.fragment;
f.mNextAnim = exitAnim;
mManager.removeFragment(f, transition, transitionStyle);
} break;
case OP_HIDE: {
Fragment f = op.fragment;
f.mNextAnim = exitAnim;
mManager.hideFragment(f, transition, transitionStyle);
} break;
case OP_SHOW: {
Fragment f = op.fragment;
f.mNextAnim = enterAnim;
mManager.showFragment(f, transition, transitionStyle);
} break;
case OP_DETACH: {
Fragment f = op.fragment;
f.mNextAnim = exitAnim;
mManager.detachFragment(f, transition, transitionStyle);
} break;
case OP_ATTACH: {
Fragment f = op.fragment;
f.mNextAnim = enterAnim;
mManager.attachFragment(f, transition, transitionStyle);
} break;
default: {
throw new IllegalArgumentException("Unknown cmd: " + op.cmd);
}
}
op = op.next;
}
mManager.moveToState(mManager.mCurState, transition, transitionStyle, true);
...
}
public void removeFragment(Fragment fragment, int transition, int transitionStyle) {
if (DEBUG) Log.v(TAG, "remove: " + fragment + " nesting=" + fragment.mBackStackNesting);
final boolean inactive = !fragment.isInBackStack();
if (!fragment.mDetached || inactive) {
if (mAdded != null) {
mAdded.remove(fragment);
}
if (fragment.mHasMenu && fragment.mMenuVisible) {
mNeedMenuInvalidate = true;
}
fragment.mAdded = false;
fragment.mRemoving = true;
moveToState(fragment, inactive ? Fragment.INITIALIZING : Fragment.CREATED,
transition, transitionStyle, false);
}
}- 走进moveToState，else if (f.mState > newState) {}这里依次进行生命周期调用。
- 所以你看。绑定最重要的看懂moveToState就好咯。