对Activity的DecorView的包装(二)

看了下公司的系统代码对于根布局decor_layout.xml的修改, 有所获.

前些时候才开始做系统开发的时候, 总想改改系统的源码, 至于原因: 人总是想装装, 在踩过几个别人修改的坑后, 还是觉得在不改源码的基础上, 尽量纳源码为自己所用还是挺好的.

代码如下:

     public void wrapDecor(Activity activity) {

         mWindow = activity.getWindow();
         if(mWindow == null){
             Log.e(TAG, "Window is null");
             return;
         }

         View decorView = mWindow.getDecorView();
         if (decorView == null) {
             Log.e(TAG, "DecorView is null");
             return;
         }

         ViewGroup contentView = (ViewGroup) decorView.findViewById(android.R.id.content);
         if (contentView == null) {
             Log.e(TAG, "DecorView is null, have you called wrapDecor after Activity#super.onCreate?");
             return;
         }

         final int childCount = contentView.getChildCount();
         if (childCount == 0) {
             // Maybe called before Activity#setContentView
             mPotentialErrorFlag |= FLAG_POTENTIAL_ERROR_SET_CONTENT;
         }

         View[] children = new View[childCount];
         for (int i = 0; i < childCount; i++) {
             children[i] = contentView.getChildAt(i);
         }

         contentView.removeAllViews();

         LayoutInflater inflater = LayoutInflater.from(activity);

         //===================== begin ========================

         // 此处即为自定义的decor_layout.xml文件
         View wrapper = inflater.inflate(R.layout.decor_layout, null);

         ViewGroup rawContentView = (ViewGroup) wrapper.findViewById(R.id.content);
         if (childCount > 0) {
             for (View child : children) {
                 rawContentView.addView(child);
             }
         }
         //change for listActivity, add view first then setContenView
         activity.setContentView(wrapper);

         //=====================   end   =======================

         // 获取自定义decor_layout中的控件
         mOptionsKey = wrapper.findViewById(R.id.feature_bar_options);

         // 此处获取的是ActionBar的控件, 由于项目中需要大量使用到ActionBar,
         // 此处对覆盖ActionBar对OptionMenu的控制
         ActionBarView actionBarView = (ActionBarView) decorView.findViewById(
                 com.android.internal.R.id.action_bar);
         if (actionBarView != null) {
             // 覆盖ActionBar对OptionMenu的控制
             actionBarView.setOverrideOverflowButton(mOptionsKey);
         } else {
             Log.d(TAG, "actionBarView is null");
             if (mWindow != null) {
                 Log.d(TAG, "Attempt to invoke setShouldOverrideResources access PhoneWindow");
                 mWindow.setShouldOverrideResources(true);
             } else {
                  Log.d(TAG, "mWindow is empty, pls check it");
             }
         }
     }

该段代码的核心, 就在上面的 begin 和 end 之间, 代码挺简单, 使用到包装的思想, 也就是包装设计模式.