原型模式(Prototype)实现与研究 - bei1999/work GitHub Wiki

 //系统调用
 Intent intent = new Intent(MainActivity09.this,MainActivity08.class);
 startActivity(intent);
 // ---------------------------------------------------------------------
 //intent 的系统源码
    /**
     * Create an empty intent.
     */
    public Intent() {
    }

    /**
     * Copy constructor.
     */
    public Intent(Intent o) {
        this.mAction = o.mAction;
        this.mData = o.mData;
        this.mType = o.mType;
        this.mPackage = o.mPackage;
        this.mComponent = o.mComponent;
        this.mFlags = o.mFlags;
        this.mContentUserHint = o.mContentUserHint;
        if (o.mCategories != null) {
            this.mCategories = new ArraySet<String>(o.mCategories);
        }
        if (o.mExtras != null) {
            this.mExtras = new Bundle(o.mExtras);
        }
        if (o.mSourceBounds != null) {
            this.mSourceBounds = new Rect(o.mSourceBounds);
        }
        if (o.mSelector != null) {
            this.mSelector = new Intent(o.mSelector);
        }
        if (o.mClipData != null) {
            this.mClipData = new ClipData(o.mClipData);
        }
    }

    @Override
    public Object clone() {
        return new Intent(this);
    }

    private Intent(Intent o, boolean all) {
        this.mAction = o.mAction;
        this.mData = o.mData;
        this.mType = o.mType;
        this.mPackage = o.mPackage;
        this.mComponent = o.mComponent;
        if (o.mCategories != null) {
            this.mCategories = new ArraySet<String>(o.mCategories);
        }
    }

    /**
     * Make a clone of only the parts of the Intent that are relevant for
     * filter matching: the action, data, type, component, and categories.
     */
    public Intent cloneFilter() {
        return new Intent(this, false);
    }

  /**
     * Same as {@link #startActivity(Intent, Bundle)} with no options
     * specified.
     *
     * @param intent The intent to start.
     *
     * @throws android.content.ActivityNotFoundException
     *
     * @see {@link #startActivity(Intent, Bundle)}
     * @see #startActivityForResult
     */
    @Override
    public void startActivity(Intent intent) {
        this.startActivity(intent, null);
    }

    @Override
    public void startActivity(Intent intent, @Nullable Bundle options) {
        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(Intent intent, int requestCode, @Nullable Bundle options) {
        if (mParent == null) {
            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);
            }
        }
    }


  public ActivityResult execStartActivity(
            Context who, IBinder contextThread, IBinder token, Activity target,
            Intent intent, int requestCode, Bundle options) {
        IApplicationThread whoThread = (IApplicationThread) contextThread;
        Uri referrer = target != null ? target.onProvideReferrer() : null;
        if (referrer != null) {
            intent.putExtra(Intent.EXTRA_REFERRER, referrer);
        }
        if (mActivityMonitors != null) {
            synchronized (mSync) {
                final int N = mActivityMonitors.size();
                for (int i=0; i<N; i++) {
                    final ActivityMonitor am = mActivityMonitors.get(i);
                    if (am.match(who, null, intent)) {
                        am.mHits++;
                        if (am.isBlocking()) {
                            return requestCode >= 0 ? am.getResult() : null;
                        }
                        break;
                    }
                }
            }
        }
        try {
            intent.migrateExtraStreamToClipData();
            intent.prepareToLeaveProcess();
//ActivityManagerNative 为一个抽象类，具体的实现在ActivityManagerService
            int result = ActivityManagerNative.getDefault()
                .startActivity(whoThread, who.getBasePackageName(), 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;
    }

//ActivityManagerService 中调用了startActivityAsUser，继续调用了mStackSupervisor.startActivityMayWait

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

    @Override
    public final int startActivityAsUser(IApplicationThread caller, String callingPackage,
            Intent intent, String resolvedType, IBinder resultTo, String resultWho, int requestCode,
            int startFlags, ProfilerInfo profilerInfo, Bundle options, int userId) {
        enforceNotIsolatedCaller("startActivity");
        userId = handleIncomingUser(Binder.getCallingPid(), Binder.getCallingUid(), userId,
                false, ALLOW_FULL_ONLY, "startActivity", null);
        // TODO: Switch to user app stacks here.
        return mStackSupervisor.startActivityMayWait(caller, -1, callingPackage, intent,
                resolvedType, null, null, resultTo, resultWho, requestCode, startFlags,
                profilerInfo, null, null, options, false, userId, null, null);
    }

// ActivityStackSuper 的startActivityMayWait 部分方法，最终调用了pms 的resolveIntent 方法
 try {
                            ResolveInfo rInfo =
                                AppGlobals.getPackageManager().resolveIntent(
                                        intent, null,
                                        PackageManager.MATCH_DEFAULT_ONLY
                                        | ActivityManagerService.STOCK_PM_FLAGS, userId);
                            aInfo = rInfo != null ? rInfo.activityInfo : null;
                            aInfo = mService.getActivityInfoForUser(aInfo, userId);
                        } catch (RemoteException e) {
                            aInfo = null;
                        }
  



//queryIntentActivitityes  主要调用了pms de resolveIntent方法

    @Override
    public List<ResolveInfo> queryIntentActivityOptions(ComponentName caller,
            Intent[] specifics, String[] specificTypes, Intent intent,
            String resolvedType, int flags, int userId) {
        if (!sUserManager.exists(userId)) return Collections.emptyList();
        enforceCrossUserPermission(Binder.getCallingUid(), userId, false,
                false, "query intent activity options");
        final String resultsAction = intent.getAction();

        List<ResolveInfo> results = queryIntentActivities(intent, resolvedType, flags
                | PackageManager.GET_RESOLVED_FILTER, userId);

        if (DEBUG_INTENT_MATCHING) {
            Log.v(TAG, "Query " + intent + ": " + results);
        }

        int specificsPos = 0;
        int N;

        // todo: note that the algorithm used here is O(N^2).  This
        // isn't a problem in our current environment, but if we start running
        // into situations where we have more than 5 or 10 matches then this
        // should probably be changed to something smarter...

        // First we go through and resolve each of the specific items
        // that were supplied, taking care of removing any corresponding
        // duplicate items in the generic resolve list.
        if (specifics != null) {
            for (int i=0; i<specifics.length; i++) {
                final Intent sintent = specifics[i];
                if (sintent == null) {
                    continue;
                }

                if (DEBUG_INTENT_MATCHING) {
                    Log.v(TAG, "Specific #" + i + ": " + sintent);
                }

                String action = sintent.getAction();
                if (resultsAction != null && resultsAction.equals(action)) {
                    // If this action was explicitly requested, then don't
                    // remove things that have it.
                    action = null;
                }

                ResolveInfo ri = null;
                ActivityInfo ai = null;

                ComponentName comp = sintent.getComponent();
                if (comp == null) {
//这里最关键
                    ri = resolveIntent(
                        sintent,
                        specificTypes != null ? specificTypes[i] : null,
                            flags, userId);
                    if (ri == null) {
                        continue;
                    }
                    if (ri == mResolveInfo) {
                        // ACK!  Must do something better with this.
                    }
                    ai = ri.activityInfo;
                    comp = new ComponentName(ai.applicationInfo.packageName,
                            ai.name);
                } else {
                    ai = getActivityInfo(comp, flags, userId);
                    if (ai == null) {
                        continue;
                    }
                }

 ／／queryIntentAactivity  返回了一个acitivtyinfo的对象列表
 ResolveInfo xpResolveInfo  = querySkipCurrentProfileIntents(matchingFilters, intent,
                        resolvedType, flags, userId);
                if (xpResolveInfo != null && isUserEnabled(xpResolveInfo.targetUserId)) {
                    List<ResolveInfo> result = new ArrayList<ResolveInfo>(1);
                    result.add(xpResolveInfo);
                    return filterIfNotPrimaryUser(result, userId);
                }

                // Check for results in the current profile.
                List<ResolveInfo> result = mActivities.queryIntent(
                        intent, resolvedType, flags, userId);

                // Check for cross profile results.
                xpResolveInfo = queryCrossProfileIntents(
                        matchingFilters, intent, resolvedType, flags, userId);

这个列表其实也就是程序入口的时候通过manifest 文件进行反射后的acitivitiy 集合

 // All available activities, for your resolving pleasure.
    final ActivityIntentResolver mActivities =
            new ActivityIntentResolver();