imsdroid啓動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。這是爲什麼呢？後來研究了一下啓動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，相當於把一個Activity作爲容器，然後把另外一個Activity放進去。也就是說，要想設置，就必須在主Activity中（或者在Manifest.xml）。