Android主题切换日夜间模式与换肤框架小结

1、Android主题切换日夜间模式

1、Google提供了夜间模式方案

• 首先你需要准备两套资源，一套日见一套夜间，以color为例：在res中新建values-night，然后新建color.xml，日间夜间资源命名要相同，但颜色不同。

• 第一步准备好，就可以这样使用，配合SharedPreferences，记录我们是开夜间还是日间，在Application这样写：

    SharedPreferences sp = getSharedPreferences("theme_mode",MODE_PRIVATE);
    boolean nightMode = sp.getBoolean("is_night_mode", false);
    AppCompatDelegate.setDefaultNightMode(nightMode ?
            AppCompatDelegate.MODE_NIGHT_YES : AppCompatDelegate.MODE_NIGHT_NO);
  

• 对于上面的，介绍下 AppCompatDelegate.setDefaultNightMode几种模式：

  MODE_NIGHT_NO： 亮色(light)主题，不使用夜间模式
  MODE_NIGHT_YES：暗色(dark)主题，使用夜间模式
  MODE_NIGHT_AUTO：根据当前时间自动切换 亮色( light )/暗色( dark )主题（22：00-07：00时间段内自动切换为夜间模式）
  MODE_NIGHT_FOLLOW_SYSTEM(默认选项)：设置为跟随系统，通常为MODE_NIGHT_NO 
  

• 在Activity中切换：

    //  获取当前模式
    int currentNightMode = getResources().getConfiguration().uiMode & Configuration.UI_MODE_NIGHT_MASK;
    //  将为夜间模式保存到SharedPreferences
    SharedPreferences sp = getSharedPreferences("theme_mode",MODE_PRIVATE);
    sp.edit().putBoolean("is_night_mode",currentNightMode == Configuration.UI_MODE_NIGHT_NO).commit();
    //  切换模式
    getDelegate().setDefaultNightMode(currentNightMode == Configuration.UI_MODE_NIGHT_NO ?
            AppCompatDelegate.MODE_NIGHT_YES : AppCompatDelegate.MODE_NIGHT_NO);
    //  重启Activity
    //recreate();  recreate存在一些问题
    startActivity(new Intent(this,MainActivity.class));
    finish();
  

2、Android-skin-support

1、使用：
github写的很详细
https://github.com/ximsfei/Android-skin-support#%E5%AF%BC%E5%85%A5
2、原理分析：
LayoutInflater有一个内部接口Factory，系统会使用它去做XML到View的转换，而系统也提供了setFactory的方法，用户设置了，则用我们设置的，这样系统就会走我们Factory的onCreateView,他会返回一个我们定制化的View。

• 首先，Activity会在onCreate中初始化Factory，我们没有设置就返回系统默认的：

  @Override
  public void installViewFactory() {
    LayoutInflater layoutInflater = LayoutInflater.from(mContext);
    if (layoutInflater.getFactory() == null) {
        LayoutInflaterCompat.setFactory(layoutInflater, this);  //系统默认的
    } else {
        if (!(LayoutInflaterCompat.getFactory(layoutInflater)
                instanceof AppCompatDelegateImplV9)) {
            Log.i(TAG, "The Activity's LayoutInflater already has a Factory installed"
                    + " so we can not install AppCompat's");
        }
    }
  }
  

• Factory会在layoutInflater.inflate，最终会走Factory.createView，看看系统的：

   @Override
  public View createView(View parent, final String name, @NonNull Context context,
        @NonNull AttributeSet attrs) {
    if (mAppCompatViewInflater == null) {
        mAppCompatViewInflater = new AppCompatViewInflater();
    }
  
    boolean inheritContext = false;
    if (IS_PRE_LOLLIPOP) {
        inheritContext = (attrs instanceof XmlPullParser)
                // If we have a XmlPullParser, we can detect where we are in the layout
                ? ((XmlPullParser) attrs).getDepth() > 1
                // Otherwise we have to use the old heuristic
                : shouldInheritContext((ViewParent) parent);
    }
  
    return mAppCompatViewInflater.createView(parent, name, context, attrs, inheritContext,
            IS_PRE_LOLLIPOP, /* Only read android:theme pre-L (L+ handles this anyway) */
            true, /* Read read app:theme as a fallback at all times for legacy reasons */
            VectorEnabledTintResources.shouldBeUsed() /* Only tint wrap the context if enabled */
    );
  }
  

• 再看下去：

  public final View createView(View parent, final String name, @NonNull Context context,
        @NonNull AttributeSet attrs, boolean inheritContext,
        boolean readAndroidTheme, boolean readAppTheme, boolean wrapContext) {
    final Context originalContext = context;
  
    // We can emulate Lollipop's android:theme attribute propagating down the view hierarchy
    // by using the parent's context
    if (inheritContext && parent != null) {
        context = parent.getContext();
    }
    if (readAndroidTheme || readAppTheme) {
        // We then apply the theme on the context, if specified
        context = themifyContext(context, attrs, readAndroidTheme, readAppTheme);
    }
    if (wrapContext) {
        context = TintContextWrapper.wrap(context);
    }
  
    View view = null;
  
    // We need to 'inject' our tint aware Views in place of the standard framework versions
    switch (name) {
        case "TextView":
            view = new AppCompatTextView(context, attrs);
            break;
        case "ImageView":
            view = new AppCompatImageView(context, attrs);
            break;
        case "Button":
            view = new AppCompatButton(context, attrs);
            break;
        case "EditText":
            view = new AppCompatEditText(context, attrs);
            break;
        case "Spinner":
            view = new AppCompatSpinner(context, attrs);
            break;
        case "ImageButton":
            view = new AppCompatImageButton(context, attrs);
            break;
        case "CheckBox":
            view = new AppCompatCheckBox(context, attrs);
            break;
        case "RadioButton":
            view = new AppCompatRadioButton(context, attrs);
            break;
        case "CheckedTextView":
            view = new AppCompatCheckedTextView(context, attrs);
            break;
        case "AutoCompleteTextView":
            view = new AppCompatAutoCompleteTextView(context, attrs);
            break;
        case "MultiAutoCompleteTextView":
            view = new AppCompatMultiAutoCompleteTextView(context, attrs);
            break;
        case "RatingBar":
            view = new AppCompatRatingBar(context, attrs);
            break;
        case "SeekBar":
            view = new AppCompatSeekBar(context, attrs);
            break;
    }
  
    if (view == null && originalContext != context) {
        // If the original context does not equal our themed context, then we need to manually
        // inflate it using the name so that android:theme takes effect.
        view = createViewFromTag(context, name, attrs);
    }
  
    if (view != null) {
        // If we have created a view, check it's android:onClick
        checkOnClickListener(view, attrs);
    }
  
    return view;
  }
  

• 可以看到系统也是根据XML解析的名字new出控件，但上面都是AppCompat类型，其他类型其实的通过类加载器创建出来的，那么XML使用TextView其实是AppCompatTextView，利用这一个原理，看看Android-skin-support：

   private View createViewFromFV(Context context, String name, AttributeSet attrs) {
    View view = null;
    if (name.contains(".")) {
        return null;
    }
    switch (name) {
        case "View":
            view = new SkinCompatView(context, attrs);
            break;
        case "LinearLayout":
            view = new SkinCompatLinearLayout(context, attrs);
            break;
        case "RelativeLayout":
            view = new SkinCompatRelativeLayout(context, attrs);
            break;
        case "FrameLayout":
            view = new SkinCompatFrameLayout(context, attrs);
            break;
        case "TextView":
            view = new SkinCompatTextView(context, attrs);
            break;
        case "ImageView":
            view = new SkinCompatImageView(context, attrs);
            break;
        case "Button":
            view = new SkinCompatButton(context, attrs);
            break;
        case "EditText":
            view = new SkinCompatEditText(context, attrs);
            break;
        case "Spinner":
            view = new SkinCompatSpinner(context, attrs);
            break;
        case "ImageButton":
            view = new SkinCompatImageButton(context, attrs);
            break;
        case "CheckBox":
            view = new SkinCompatCheckBox(context, attrs);
            break;
        case "RadioButton":
            view = new SkinCompatRadioButton(context, attrs);
            break;
        case "RadioGroup":
            view = new SkinCompatRadioGroup(context, attrs);
            break;
        case "CheckedTextView":
            view = new SkinCompatCheckedTextView(context, attrs);
            break;
        case "AutoCompleteTextView":
            view = new SkinCompatAutoCompleteTextView(context, attrs);
            break;
        case "MultiAutoCompleteTextView":
            view = new SkinCompatMultiAutoCompleteTextView(context, attrs);
            break;
        case "RatingBar":
            view = new SkinCompatRatingBar(context, attrs);
            break;
        case "SeekBar":
            view = new SkinCompatSeekBar(context, attrs);
            break;
        case "ProgressBar":
            view = new SkinCompatProgressBar(context, attrs);
            break;
        case "ScrollView":
            view = new SkinCompatScrollView(context, attrs);
            break;
    }
    return view;
  }
  

• 这就返回了自己定制好的View了，那么回到前面，我们需要在super.onCreate前设置自己的Factory，不可能每个Activity都设置一遍，那么利用Application.ActivityLifecycleCallbacks统一设置：

   @Override
    public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
        if (activity instanceof AppCompatActivity) {
            LayoutInflater layoutInflater = activity.getLayoutInflater();
            try {
                Field field = LayoutInflater.class.getDeclaredField("mFactorySet");
                field.setAccessible(true);
                field.setBoolean(layoutInflater, false);
                LayoutInflaterCompat.setFactory(activity.getLayoutInflater(),
                        getSkinDelegate((AppCompatActivity) activity));
            } catch (NoSuchFieldException | IllegalArgumentException | IllegalAccessException e) {
                e.printStackTrace();
            }
            updateStatusBarColor(activity);
            updateWindowBackground(activity);
        }
    }