Android技术揭秘之activity堆栈管理

Posted 2022-05-31 王永迪

定义activity基类

public class BaseActivity extends Activity 

    /** activity 入栈 */
    @Override
    protected void onCreate(Bundle savedInstanceState)
        super.onCreate(savedInstanceState);
        ActivitiesManager.getInstance().pushActivity(this);
    

    /** activity 出栈 */
    @Override
    protected void onDestroy() 
        super.onDestroy();
        ActivitiesManager.getInstance().popActivity();
    

activity堆栈管理器

public class ActivitiesManager 

    private static final String TAG = "ActivitiesManager";
    private Stack<Activity> mActivityStack = new Stack<Activity>()

    static class SingletonHolder 
        static ActivitiesManager instance = new ActivitiesManager();
    

    public static ActivitiesManager getInstance() 
        return SingletonHolder.instance;
    

    private EventDispatcher() 
    

    public int stackSize() 
        return mActivityStack.size();
    

    public Activity getCurrentActivity() 
        Activity activity = null;
        try 
            activity = mActivityStack.lastElement();
         catch (Exception e) 
            return null;
        
        return activity;
    

    public void popActivity() 
        Activity activity = mActivityStack.lastElement();
        if (null != activity) 
            activity.finish();
            mActivityStack.remove(activity);
            activity = null;
        
    

    public void popActivity(Activity activity) 
        if (null != activity) 
            mActivityStack.remove(activity);
            activity = null;
        
    

    public void pushActivity(Activity activity) 
        mActivityStack.add(activity);
    

    public void popAllActivities() 
        while (!mActivityStack.isEmpty()) 
        Activity activity = getCurrentActivity();
        if (null == activity) 
            break;
        
        activity.finish();
        popActivity(activity);
        
    

    public void popSpecialActivity(Class<?> cls) 
        try 
            Iterator<Activity> iterator = mActivityStack.iterator();
            Activity activity = null;
            while (iterator.hasNext()) 
                activity = iterator.next();
                if (activity.getClass().equals(cls)) 
                    activity.finish();
                    iterator.remove();
                    activity = null;
                
            
             catch (Exception e) 
        
    

    /** 查看当前的所有活动 */
    public void peekActivity() 
        for (Activity activity : mActivityStack) 
            if (null == activity) 
                break;