對Activity的DecorView的包裝(二)

看了下公司的系統代碼對於根佈局decor_layout.xml的修改, 有所獲.

前些時候才開始做系統開發的時候, 總想改改系統的源碼, 至於原因: 人總是想裝裝, 在踩過幾個別人修改的坑後, 還是覺得在不改源碼的基礎上, 儘量納源碼為自己所用還是挺好的.

代碼如下:

 1     public void wrapDecor(Activity activity) {
 2 
 3         mWindow = activity.getWindow();
 4         if(mWindow == null){
 5             Log.e(TAG, "Window is null");
 6             return;
 7         }
 8         
 9         View decorView = mWindow.getDecorView();
10         if (decorView == null) {
11             Log.e(TAG, "DecorView is null");
12             return;
13         }
14 
15         ViewGroup contentView = (ViewGroup) decorView.findViewById(android.R.id.content);
16         if (contentView == null) {
17             Log.e(TAG, "DecorView is null, have you called wrapDecor after Activity#super.onCreate?");
18             return;
19         }
20 
21         final int childCount = contentView.getChildCount();
22         if (childCount == 0) {
23             // Maybe called before Activity#setContentView
24             mPotentialErrorFlag |= FLAG_POTENTIAL_ERROR_SET_CONTENT;
25         }
26 
27         View[] children = new View[childCount];
28         for (int i = 0; i < childCount; i++) {
29             children[i] = contentView.getChildAt(i);
30         }
31 
32         contentView.removeAllViews();
33 
34         LayoutInflater inflater = LayoutInflater.from(activity);
35 
36         //===================== begin ========================
37 
38         // 此處即為自定義的decor_layout.xml文件
39         View wrapper = inflater.inflate(R.layout.decor_layout, null);
40 
41         ViewGroup rawContentView = (ViewGroup) wrapper.findViewById(R.id.content);
42         if (childCount > 0) {
43             for (View child : children) {
44                 rawContentView.addView(child);
45             }
46         }
47         //change for listActivity, add view first then setContenView
48         activity.setContentView(wrapper);
49 
50         //=====================   end   =======================
51 
52         // 獲取自定義decor_layout中的控制項
53         mOptionsKey = wrapper.findViewById(R.id.feature_bar_options);
54 
55         // 此處獲取的是ActionBar的控制項, 由於項目中需要大量使用到ActionBar, 
56         // 此處對覆蓋ActionBar對OptionMenu的控制
57         ActionBarView actionBarView = (ActionBarView) decorView.findViewById(
58                 com.android.internal.R.id.action_bar);
59         if (actionBarView != null) {
60             // 覆蓋ActionBar對OptionMenu的控制
61             actionBarView.setOverrideOverflowButton(mOptionsKey);
62         } else {
63             Log.d(TAG, "actionBarView is null");
64             if (mWindow != null) {
65                 Log.d(TAG, "Attempt to invoke setShouldOverrideResources access PhoneWindow");
66                 mWindow.setShouldOverrideResources(true);
67             } else {
68                  Log.d(TAG, "mWindow is empty, pls check it");
69             }
70         }
71     }

該段代碼的核心, 就在上面的 begin 和 end 之間, 代碼挺簡單, 使用到包裝的思想, 也就是包裝設計模式.