实现夜间模式,不需要recreate,不闪屏

通过资源 id 映射，回调自定义 ThemeChangeListener 接口来处理日间/夜间模式的切换。

在values下面colors.xml里面

xml version="1.0" encoding="utf-8"?>
<resources>

 <color name="colorPrimary">#3F51B5color>
 <color name="colorPrimary_night">#3b3b3bcolor>
 <color name="colorPrimaryDark">#303F9Fcolor>
 <color name="colorPrimaryDark_night">#383838color>
 <color name="colorAccent">#FF4081color>
 <color name="colorAccent_night">#a72b55color>
 <color name="textColor">#FF000000color>
 <color name="textColor_night">#FFFFFFcolor>
 <color name="backgroundColor">#FFFFFFcolor>
 <color name="backgroundColor_night">#3b3b3bcolor>

resources>

需要一个主题管理类 ThemeManager

public class ThemeManager {

 // 默认是日间模式
 private static ThemeMode mThemeMode = ThemeMode.DAY;
 // 主题模式监听器
 private static List<OnThemeChangeListener> mThemeChangeListenerList = new LinkedList<>();
 // 夜间资源的缓存，key : 资源类型, 值<key:资源名称, value:int值>
 private static HashMap<String, HashMap<String, Integer>> sCachedNightResrouces = new HashMap<>();
 // 夜间模式资源的后缀，比如日件模式资源名为：R.color.activity_bg, 那么夜间模式就为 ：R.color.activity_bg_night
 private static final String RESOURCE_SUFFIX = "_night";

 /**
  * 主题模式，分为日间模式和夜间模式
  */
 public enum ThemeMode {
  DAY, NIGHT
 }

 /**
  * 设置主题模式
  *
  * @param themeMode
  */
 public static void setThemeMode(ThemeMode themeMode) {
  if (mThemeMode != themeMode) {
   mThemeMode = themeMode;
   if (mThemeChangeListenerList.size() > 0) {
    for (OnThemeChangeListener listener : mThemeChangeListenerList) {
     listener.onThemeChanged();
    }
   }
  }
 }

 /**
  * 根据传入的日间模式的resId得到相应主题的resId，注意：必须是日间模式的resId
  *
  * @param dayResId 日间模式的resId
  * @return 相应主题的resId，若为日间模式，则得到dayResId；反之夜间模式得到nightResId
  */
 public static int getCurrentThemeRes(Context context, int dayResId) {
  if (getThemeMode() == ThemeMode.DAY) {
   return dayResId;
  }
  // 资源名
  String entryName = context.getResources().getResourceEntryName(dayResId);
  // 资源类型
  String typeName = context.getResources().getResourceTypeName(dayResId);
  HashMap<String, Integer> cachedRes = sCachedNightResrouces.get(typeName);
  // 先从缓存中去取，如果有直接返回该id
  if (cachedRes == null) {
   cachedRes = new HashMap<>();
  }
  Integer resId = cachedRes.get(entryName + RESOURCE_SUFFIX);
  if (resId != null && resId != 0) {
   return resId;
  } else {
   //如果缓存中没有再根据资源id去动态获取
   try {
    // 通过资源名，资源类型，包名得到资源int值
    int nightResId = context.getResources().getIdentifier(entryName + RESOURCE_SUFFIX, typeName, context.getPackageName());
    // 放入缓存中
    cachedRes.put(entryName + RESOURCE_SUFFIX, nightResId);
    sCachedNightResrouces.put(typeName, cachedRes);
    return nightResId;
   } catch (Resources.NotFoundException e) {
    e.printStackTrace();
   }
  }
  return 0;
 }

 /**
  * 注册ThemeChangeListener
  *
  * @param listener
  */
 public static void registerThemeChangeListener(OnThemeChangeListener listener) {
  if (!mThemeChangeListenerList.contains(listener)) {
   mThemeChangeListenerList.add(listener);
  }
 }

 /**
  * 反注册ThemeChangeListener
  *
  * @param listener
  */
 public static void unregisterThemeChangeListener(OnThemeChangeListener listener) {
  if (mThemeChangeListenerList.contains(listener)) {
   mThemeChangeListenerList.remove(listener);
  }
 }

 /**
  * 得到主题模式
  *
  * @return
  */
 public static ThemeMode getThemeMode() {
  return mThemeMode;
 }

 /**
  * 主题模式切换监听器
  */
 public interface OnThemeChangeListener {
  /**
   * 主题切换时回调
   */
  void onThemeChanged();
 }
}

activity_main.xml里面只需要写一个按钮,然后给根布局一个id(因为需要改变根布局的背景颜色)

在MainActivity.java找到按钮的id和根布局的id

在 MainActivity 中实现了 OnThemeChangeListener 接口，这样就可以在主题改变的时候执行回调方法。然后在 initTheme() 中去重新设置 UI 的相关颜色属性值。还有别忘了要在 onDestroy() 中移除 ThemeChangeListener 。

[html] view plain copy

public class MainActivity extends AppCompatActivity implements ThemeManager.OnThemeChangeListener {

 private TextView tv;
 private Button btn_theme;
 private RelativeLayout relativeLayout;
 private ActionBar supportActionBar;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  ThemeManager.registerThemeChangeListener(this);
  supportActionBar = getSupportActionBar();
  btn_theme = (Button) findViewById(R.id.btn_theme);
  relativeLayout = (RelativeLayout) findViewById(R.id.relativeLayout);
  tv = (TextView) findViewById(R.id.tv);
  btn_theme.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View v) {
    ThemeManager.setThemeMode(ThemeManager.getThemeMode() == ThemeManager.ThemeMode.DAY
      ? ThemeManager.ThemeMode.NIGHT : ThemeManager.ThemeMode.DAY);
   }
  });
 }

 public void initTheme() {
  tv.setTextColor(getResources().getColor(ThemeManager.getCurrentThemeRes(MainActivity.this, R.color.textColor)));
  btn_theme.setTextColor(getResources().getColor(ThemeManager.getCurrentThemeRes(MainActivity.this, R.color.textColor)));
  relativeLayout.setBackgroundColor(getResources().getColor(ThemeManager.getCurrentThemeRes(MainActivity.this, R.color.backgroundColor)));
  // 设置标题栏颜色
  if(supportActionBar != null){
   supportActionBar.setBackgroundDrawable(new ColorDrawable(getResources().getColor(ThemeManager.getCurrentThemeRes(MainActivity.this, R.color.colorPrimary))));
  }
  // 设置状态栏颜色
  if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
   Window window = getWindow();
   window.setStatusBarColor(getResources().getColor(ThemeManager.getCurrentThemeRes(MainActivity.this, R.color.colorPrimary)));
  }
 }

 @Override
 public void onThemeChanged() {
  initTheme();
 }

 @Override
 protected void onDestroy() {
  super.onDestroy();
  ThemeManager.unregisterThemeChangeListener(this);
 }

}