最近需求多了个日夜模式变换，但是大多页面都是WindowManager的弹窗。每次都要写大量的代码来动态设置背景文字颜色啥的（弹窗不管悬浮在哪，都要实时和日夜模式保持一致），感觉太浪费时间。所以最近抽空研究了一下，最后想了个办法，解析xml获取属性，传个RootView和xml，让他自己去干这些重复设置样式的活。

public interface UIModeListener {
    void uiModeChanged(boolean isLight);
}

public class UIModeManager {
    private List<UIModeListener> uiModeListenerList = new ArrayList<>();
    private static UIModeManager instance = new UIModeManager();

    public static UIModeManager getInstance() {
        return instance;
    }

    public void registerUIModeListener(UIModeListener uiModeListener) {
        boolean hava = false;
        for (int i = 0; i < uiModeListenerList.size(); i++) {
            if (uiModeListenerList.get(i) == uiModeListener) {
                hava = true;
            }
        }
        if (!hava) {
            uiModeListenerList.add(uiModeListener);
        }
    }

    public void unRegisterUIModeListener(UIModeListener uiModeListener) {
        uiModeListenerList.remove(uiModeListener);
    }

    public void broadCastUiModeChanged(boolean isLight) {
        for (int i = 0; i < uiModeListenerList.size(); i++) {
            uiModeListenerList.get(i).uiModeChanged(isLight);
        }
    }

}


/**
 * @author XHD
 * Date 2022/08/25
 * Description:View上必须设置Id，src textColor background如果引用了资源文件会重新更新
 */
public class LayoutUtils {
    private static final String TAG = LayoutUtils.class.getSimpleName() + "-------->";

    public static void updateResUI(Context context, @LayoutRes int layoutId, View rootView) {
        XmlResourceParser xmlParser = context.getResources().getLayout(layoutId);
        try {
            int event = xmlParser.getEventType();
            while (event != XmlPullParser.END_DOCUMENT) {
                switch (event) {
                    case XmlPullParser.START_DOCUMENT:
                        Log.i(TAG, "xml解析开始");
                        break;
                    case XmlPullParser.START_TAG:
                        String id = xmlParser.getAttributeValue("http://schemas.android.com/apk/res/android", "id");
                        if (checkAttr(id)) {
                            id = id.replace("@", "");
                            View view = rootView.findViewById(Integer.parseInt(id));
                            String background = xmlParser.getAttributeValue("http://schemas.android.com/apk/res/android", "background");
                            String src = xmlParser.getAttributeValue("http://schemas.android.com/apk/res/android", "src");
                            String textColor = xmlParser.getAttributeValue("http://schemas.android.com/apk/res/android", "textColor");
                            if (checkAttr(background)) {
                                background = background.replace("@", "");
                                view.setBackground(context.getResources().getDrawable(Integer.parseInt(background)));
                                Log.e(TAG, "update background");
                            }
                            if (view instanceof ImageView && checkAttr(src)) {
                                src = src.replace("@", "");
                                ((ImageView) view).setImageDrawable(context.getResources().getDrawable(Integer.parseInt(src)));
                                Log.e(TAG, "update src");
                            }
                            if (view instanceof TextView && checkAttr(textColor)) {
                                textColor = textColor.replace("@", "");
                                ((TextView) view).setTextColor(context.getResources().getColor(Integer.parseInt(textColor)));
                                Log.e(TAG, "update textColor");
                            }
                        }
                        break;
                    case XmlPullParser.TEXT:
                        Log.d(TAG, "Text:" + xmlParser.getText());
                        break;
                    case XmlPullParser.END_TAG:
                        break;
                    default:
                        break;
                }
                event = xmlParser.next();
            }
        } catch (XmlPullParserException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private static boolean checkAttr(String attr) {
        if (!TextUtils.isEmpty(attr) && !attr.equals("null") && attr.contains("@")) {
            return true;
        }
        return false;
    }
}

MainApplication中注册日夜模式变化监听

public class MainApplication extends Application {
    public static MainApplication instance;

    @Override
    public void onCreate() {
        super.onCreate();
        instance = this;
    }

    @Override
    public void onConfigurationChanged(@NonNull Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        int currentNightMode = newConfig.uiMode & Configuration.UI_MODE_NIGHT_MASK;
        switch (currentNightMode) {
            case Configuration.UI_MODE_NIGHT_NO:
                log("onConfigurationChanged: uiMode=白天模式");
                UIModeManager.getInstance().broadCastUiModeChanged(true);
                break;
            case Configuration.UI_MODE_NIGHT_YES:
                log("onConfigurationChanged: uiMode=黑夜模式");
                UIModeManager.getInstance().broadCastUiModeChanged(false);
                break;
        }
    }

    private void log(String msg) {
        Log.e(MainApplication.class.getSimpleName() + "-------->", msg);
    }
}

Activity中进行注册

public class MainActivity extends AppCompatActivity implements UIModeListener {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        UIModeManager.getInstance().registerUIModeListener(this);
    }

    @Override
    public void uiModeChanged(boolean isLight) {
        Log.e(MainActivity.class.getSimpleName() + "------->", "uiModeChanged: isLight=" + isLight);
        LayoutUtils.updateResUI(MainApplication.instance, R.layout.activity_main, getWindow().getDecorView());
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        UIModeManager.getInstance().unRegisterUIModeListener(this);
    }
}

最后又利用插件化思路，改进了上面的方法，可以直接加载插件apk，获取插件的Resource，再从插件的Resource中获取资源文件或样式，这样就可以实现通用的动态换肤了。

最后附上完整demo地址

DarkDemo