imsdroid啟動Activity的方式很獨特

　　近來在調試imsdroid，想限制轉屏。結果發現常用的辦法無效。這是為什麼呢？後來研究了一下啟動Activity的代碼，有點獨特。具體代碼是：

@Override
    public boolean show(Class<? extends Activity> cls, String id) {
        final Main mainActivity = (Main)Engine.getInstance().getMainActivity();
        
        String screen_id = (id == null) ? cls.getCanonicalName() : id;
        Intent intent = new Intent(mainActivity, cls);
        intent.putExtra("id", screen_id);
        intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        final Window window = mainActivity.getLocalActivityManager().startActivity(screen_id, intent);
        if(window != null){
            View view = mainActivity.getLocalActivityManager().startActivity(screen_id, intent).getDecorView();
            
            LinearLayout layout = (LinearLayout) mainActivity.findViewById(R.id.main_linearLayout_principal);
            layout.removeAllViews();
            layout.addView(view, new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
            
            // add to stack
            this.mLastScreens[(++this.mLastScreensIndex % this.mLastScreens.length)] = screen_id;
            this.mLastScreensIndex %= this.mLastScreens.length;
            return true;
        }
        return false;
    }      

　　初步分析來說，相當于把一個Activity作為容器，然後把另外一個Activity放進去。也就是說，要想設定，就必須在主Activity中（或者在Manifest.xml）。