StartActivity 호출 시 코드 진행 순서 1

같이 한 번 알아봅시다~

분석 내용에 대한 sequence

 

Activity.java

---

	...

    @Override
    public void startActivity(Intent intent) {
        this.startActivity(intent, null);
    }
 
	...
 
    @Override
    public void startActivity(Intent intent, @Nullable Bundle options) {
        if (mIntent != null && mIntent.hasExtra(AutofillManager.EXTRA_RESTORE_SESSION_TOKEN)
                && mIntent.hasExtra(AutofillManager.EXTRA_RESTORE_CROSS_ACTIVITY)) {
            if (TextUtils.equals(getPackageName(),
                    intent.resolveActivity(getPackageManager()).getPackageName())) {
                // Apply Autofill restore mechanism on the started activity by startActivity()
                final IBinder token =
                        mIntent.getIBinderExtra(AutofillManager.EXTRA_RESTORE_SESSION_TOKEN);
                // Remove restore ability from current activity
                mIntent.removeExtra(AutofillManager.EXTRA_RESTORE_SESSION_TOKEN);
                mIntent.removeExtra(AutofillManager.EXTRA_RESTORE_CROSS_ACTIVITY);
                // Put restore token
                intent.putExtra(AutofillManager.EXTRA_RESTORE_SESSION_TOKEN, token);
                intent.putExtra(AutofillManager.EXTRA_RESTORE_CROSS_ACTIVITY, true);
            }
        }
        if (options != null) {
            startActivityForResult(intent, -1, options);
        } else {
            // Note we want to go through this call for compatibility with
            // applications that may have overridden the method.
            startActivityForResult(intent, -1);
        }
    }
    
    ...
    
    public void startActivityForResult(@RequiresPermission Intent intent, int requestCode) {
        startActivityForResult(intent, requestCode, null);
    }
    
    public void startActivityForResult(@RequiresPermission Intent intent, int requestCode,
            @Nullable Bundle options) {
        if (mParent == null) {
            options = transferSpringboardActivityOptions(options);
            Instrumentation.ActivityResult ar =
                mInstrumentation.execStartActivity(
                    this, mMainThread.getApplicationThread(), mToken, this,
                    intent, requestCode, options);
            if (ar != null) {
                mMainThread.sendActivityResult(
                    mToken, mEmbeddedID, requestCode, ar.getResultCode(),
                    ar.getResultData());
            }
            if (requestCode >= 0) {
                // If this start is requesting a result, we can avoid making
                // the activity visible until the result is received.  Setting
                // this code during onCreate(Bundle savedInstanceState) or onResume() will keep the
                // activity hidden during this time, to avoid flickering.
                // This can only be done when a result is requested because
                // that guarantees we will get information back when the
                // activity is finished, no matter what happens to it.
                mStartedActivity = true;
            }

            cancelInputsAndStartExitTransition(options);
            // TODO Consider clearing/flushing other event sources and events for child windows.
        } else {
            if (options != null) {
                mParent.startActivityFromChild(this, intent, requestCode, options);
            } else {
                // Note we want to go through this method for compatibility with
                // existing applications that may have overridden it.
                mParent.startActivityFromChild(this, intent, requestCode);
            }
        }
    }

Activity 내에서 startActivity를 호출해주게 될 경우, 프레임워크 단의 

public void startActivityForResult(@RequiresPermission Intent intent, int requestCode,
        @Nullable Bundle options) {

메서드가 불리게 된다

결국 해당 메서드를 확인해보면 mInstrumentation.execStartActivity 부분이 호출되게 된다

 

mInstrumentation.execStartActivity(
    this, mMainThread.getApplicationThread(), mToken, this, // 혹은 child
    intent, requestCode, options);

 

 

 

 

instrumentation.java

---

    @UnsupportedAppUsage
    public ActivityResult execStartActivity(
            Context who, IBinder contextThread, IBinder token, Activity target,
            Intent intent, int requestCode, Bundle options) {
            
            ...
            
                    try {
            intent.migrateExtraStreamToClipData(who);
            intent.prepareToLeaveProcess(who);
            int result = ActivityTaskManager.getService().startActivity(whoThread,
                    who.getOpPackageName(), who.getAttributionTag(), intent,
                    intent.resolveTypeIfNeeded(who.getContentResolver()), token,
                    target != null ? target.mEmbeddedID : null, requestCode, 0, null, options);
            checkStartActivityResult(result, intent);
        } catch (RemoteException e) {
            throw new RuntimeException("Failure from system", e);
        }
        return null;
    }

ActivityTaskManagerService의 startActivity를 호출 해 준다

 

 

 

 

 

 

ActivityTaskManagerService.java

---

	...
    
	ActivityStartController getActivityStartController() {
        return mActivityStartController;
    }
    
	...
    
    @Override
    public final int startActivity(IApplicationThread caller, String callingPackage,
            String callingFeatureId, Intent intent, String resolvedType, IBinder resultTo,
            String resultWho, int requestCode, int startFlags, ProfilerInfo profilerInfo,
            Bundle bOptions) {
        return startActivityAsUser(caller, callingPackage, callingFeatureId, intent, resolvedType,
                resultTo, resultWho, requestCode, startFlags, profilerInfo, bOptions,
                UserHandle.getCallingUserId());
    }


	...
 
     @Override
    public int startActivityAsUser(IApplicationThread caller, String callingPackage,
            String callingFeatureId, Intent intent, String resolvedType, IBinder resultTo,
            String resultWho, int requestCode, int startFlags, ProfilerInfo profilerInfo,
            Bundle bOptions, int userId) {
        return startActivityAsUser(caller, callingPackage, callingFeatureId, intent, resolvedType,
                resultTo, resultWho, requestCode, startFlags, profilerInfo, bOptions, userId,
                true /*validateIncomingUser*/);
    }
    
 	...
    
     private int startActivityAsUser(IApplicationThread caller, String callingPackage,
            @Nullable String callingFeatureId, Intent intent, String resolvedType,
            IBinder resultTo, String resultWho, int requestCode, int startFlags,
            ProfilerInfo profilerInfo, Bundle bOptions, int userId, boolean validateIncomingUser) {
        assertPackageMatchesCallingUid(callingPackage);
        enforceNotIsolatedCaller("startActivityAsUser");

        userId = getActivityStartController().checkTargetUser(userId, validateIncomingUser,
                Binder.getCallingPid(), Binder.getCallingUid(), "startActivityAsUser");

        // TODO: Switch to user app stacks here.
        return getActivityStartController().obtainStarter(intent, "startActivityAsUser")
                .setCaller(caller)
                .setCallingPackage(callingPackage)
                .setCallingFeatureId(callingFeatureId)
                .setResolvedType(resolvedType)
                .setResultTo(resultTo)
                .setResultWho(resultWho)
                .setRequestCode(requestCode)
                .setStartFlags(startFlags)
                .setProfilerInfo(profilerInfo)
                .setActivityOptions(bOptions)
                .setUserId(userId)
                .execute();

    }

ActivityTaskManagerService의 startActivityAsUser에서는

Builder patter 형식으로 ActivityStartController를 통해 ontainStarter를 해주고

ActivityStarter의 execute 메서드를 호출 시킨다

 

 

 

 

 

 

ActivityStartController.java

---

...

    private final Factory mFactory;
    
    ...
    
    ActivityStartController(ActivityTaskManagerService service) {
        this(service, service.mTaskSupervisor,
                new DefaultFactory(service, service.mTaskSupervisor,
                    new ActivityStartInterceptor(service, service.mTaskSupervisor)));
    }
    
    ...

	ActivityStarter obtainStarter(Intent intent, String reason) {
        return mFactory.obtain().setIntent(intent).setReason(reason);
    }

ActivityStartController는 생성시에 ActivityStarter에서 static으로 선언되어 있는 DefaultFactory를 생성한다

그리고, ActivityTaskManager의 startActivityAsUser에서 ActivityStarter의 execute를 호출해준다

 

 

 

 

 

 

 

ActivityStarter.java (Factory)

---

    @VisibleForTesting
    interface Factory {
        /**
         * Sets the {@link ActivityStartController} to be passed to {@link ActivityStarter}.
         */
        void setController(ActivityStartController controller);

        /**
         * Generates an {@link ActivityStarter} that is ready to handle a new start request.
         * @param controller The {@link ActivityStartController} which the starter who will own
         *                   this instance.
         * @return an {@link ActivityStarter}
         */
        ActivityStarter obtain();

        /**
         * Recycles a starter for reuse.
         */
        void recycle(ActivityStarter starter);
    }
    
	...
    
     /**
     * Default implementation of {@link StarterFactory}.
     */
    static class DefaultFactory implements Factory {
    
    ...
  
          DefaultFactory(ActivityTaskManagerService service,
                ActivityTaskSupervisor supervisor, ActivityStartInterceptor interceptor) {
            mService = service;
            mSupervisor = supervisor;
            mInterceptor = interceptor;
        }
        
     ...
  
         @Override
        public ActivityStarter obtain() {
            ActivityStarter starter = mStarterPool.acquire();

            if (starter == null) {
                if (mService.mRootWindowContainer == null) {
                    throw new IllegalStateException("Too early to start activity.");
                }
                starter = new ActivityStarter(mController, mService, mSupervisor, mInterceptor);
            }

            return starter;
        }
        
	...

 

 

 

 

 

 

ActivityStarter.java (execute)

---

    /**
     * Resolve necessary information according the request parameters provided earlier, and execute
     * the request which begin the journey of starting an activity.
     * @return The starter result.
     */
    int execute() {
        try {
            // Refuse possible leaked file descriptors
            if (mRequest.intent != null && mRequest.intent.hasFileDescriptors()) {
                throw new IllegalArgumentException("File descriptors passed in Intent");
            }
            
     ...
     
            int res;
            synchronized (mService.mGlobalLock) {
                final boolean globalConfigWillChange = mRequest.globalConfig != null
                        && mService.getGlobalConfiguration().diff(mRequest.globalConfig) != 0;
                final Task rootTask = mRootWindowContainer.getTopDisplayFocusedRootTask();
                if (rootTask != null) {
                    rootTask.mConfigWillChange = globalConfigWillChange;
                }
                ProtoLog.v(WM_DEBUG_CONFIGURATION, "Starting activity when config "
                        + "will change = %b", globalConfigWillChange);

                final long origId = Binder.clearCallingIdentity();

                res = resolveToHeavyWeightSwitcherIfNeeded();
                if (res != START_SUCCESS) {
                    return res;
                }
                res = executeRequest(mRequest);  // 여기
                
 	...
    
                mSupervisor.getActivityMetricsLogger().notifyActivityLaunched(launchingState, res,
                        newActivityCreated, mLastStartActivityRecord, originalOptions);
                if (mRequest.waitResult != null) {
                    mRequest.waitResult.result = res;
                    res = waitResultIfNeeded(mRequest.waitResult, mLastStartActivityRecord,
                            launchingState);
                }
                return getExternalResult(res);
            }
        } finally {
            onExecutionComplete();
        }

ActivityStarter의 execute 에서 중요한 것은 executeRequest를 호출 해주는 부분입니다

 

 

 

 

 

 

 

 

ActivityStarter.java (executeRequest)

---

    private int executeRequest(Request request) {
        if (TextUtils.isEmpty(request.reason)) {
            throw new IllegalArgumentException("Need to specify a reason.");
        }
        
        ...
        
        WindowProcessController homeProcess = mService.mHomeProcess;
        boolean isHomeProcess = homeProcess != null
                && aInfo.applicationInfo.uid == homeProcess.mUid;
        if (!restrictedBgActivity && !isHomeProcess) {
            mService.resumeAppSwitches();
        }

        mLastStartActivityResult = startActivityUnchecked(r, sourceRecord, voiceSession,
                request.voiceInteractor, startFlags, true /* doResume */, checkedOptions,
                inTask, inTaskFragment, restrictedBgActivity, intentGrants);

        if (request.outActivity != null) {
            request.outActivity[0] = mLastStartActivityRecord;
        }

        return mLastStartActivityResult;
    }

executeRequest 메서드 안도 매우 복잡하지만 startActivity가 이루어지는 부분을 보려면 

startActivityUnchecked 부분만 보면 됩니다

 

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