【Android4.2系統源碼】Activity學習

先看看Activity繼承了哪些東西：

public class Activity extends ContextThemeWrapper
        implements LayoutInflater.Factory2,
        Window.Callback, KeyEvent.Callback,
        OnCreateContextMenuListener, ComponentCallbacks2

ContextThemeWrapper 主題包裝？
來看張圖：

接着是一些接口：
LayoutInflater.Factory2,Window.Callback, KeyEvent.Callback,OnCreateContextMenuListener,ComponentCallbacks2

關於Activity的onCreate

protected void onCreate(Bundle savedInstanceState) {
        if (DEBUG_LIFECYCLE) Slog.v(TAG, "onCreate " + this + ": " + savedInstanceState);
        if (mLastNonConfigurationInstances != null) {
            mAllLoaderManagers = mLastNonConfigurationInstances.loaders;
        }
        if (mActivityInfo.parentActivityName != null) {
            if (mActionBar == null) {
                mEnableDefaultActionBarUp = true;
            } else {
                mActionBar.setDefaultDisplayHomeAsUpEnabled(true);
            }
        }
        if (savedInstanceState != null) {
            Parcelable p = savedInstanceState.getParcelable(FRAGMENTS_TAG);
            mFragments.restoreAllState(p, mLastNonConfigurationInstances != null
                    ? mLastNonConfigurationInstances.fragments : null);
        }
        mFragments.dispatchCreate();
        getApplication().dispatchActivityCreated(this, savedInstanceState);
        mCalled = true;
    }

DEBUG_LIFECYCLE是標識生命週期，
NonConfigurationInstances在上文是這麼定義的：

static final class NonConfigurationInstances {
        Object activity;
        HashMap<String, Object> children;
        ArrayList<Fragment> fragments;
        HashMap<String, LoaderManagerImpl> loaders;
    }

然後是onpause

protected void onPause() {
        if (DEBUG_LIFECYCLE) Slog.v(TAG, "onPause " + this);
        getApplication().dispatchActivityPaused(this);
        mCalled = true;
    }

生命週期進入停止狀態，但未殺死

關於onStop

 protected void onStop() {
        if (DEBUG_LIFECYCLE) Slog.v(TAG, "onStop " + this);
        if (mActionBar != null) mActionBar.setShowHideAnimationEnabled(false);
        getApplication().dispatchActivityStopped(this);
        mCalled = true;
    }

關於OnDestory

protected void onDestroy() {
        if (DEBUG_LIFECYCLE) Slog.v(TAG, "onDestroy " + this);
        mCalled = true;

        // dismiss any dialogs we are managing.
        if (mManagedDialogs != null) {
            final int numDialogs = mManagedDialogs.size();
            for (int i = 0; i < numDialogs; i++) {
                final ManagedDialog md = mManagedDialogs.valueAt(i);
                if (md.mDialog.isShowing()) {
                    md.mDialog.dismiss();
                }
            }
            mManagedDialogs = null;
        }

        // close any cursors we are managing.
        synchronized (mManagedCursors) {
            int numCursors = mManagedCursors.size();
            for (int i = 0; i < numCursors; i++) {
                ManagedCursor c = mManagedCursors.get(i);
                if (c != null) {
                    c.mCursor.close();
                }
            }
            mManagedCursors.clear();
        }

        // Close any open search dialog
        if (mSearchManager != null) {
            mSearchManager.stopSearch();
        }

        getApplication().dispatchActivityDestroyed(this);
    }