<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
        <!--toolbar小汉堡样式-->
        <item name="drawerArrowStyle">@style/DrawerArrowStyle</item>
        <item name="android:windowBackground">@android:color/white</item>
    </style>

    <style name="AppTheme.Black">
        <item name="android:windowBackground">@android:color/black</item>
    </style>

    <!--小汉堡颜色为白色-->
    <style name="DrawerArrowStyle" parent="@style/Widget.AppCompat.DrawerArrowToggle">
        <item name="color">@android:color/white</item>
    </style>

           private static int mTheme = -1;

           @Override
           protected void onCreate(Bundle savedInstanceState) {

          // 设置主题，必须在 super.onCreate 之前执行
          if (mTheme!=-1){
               setTheme(mTheme);
          }

          super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

         findViewById(R.id.btn_default).setOnClickListener(this);
             findViewById(R.id.btn_black).setOnClickListener(this);

         }

    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.btn_default:
                mTheme = R.style.AppTheme;

                break;
            case R.id.btn_black:
                mTheme = R.style.AppTheme_Black;
                break;
        }

        Intent intent = new Intent(this,MainActivity.class);
        startActivity(intent);
        // 设置转场动画，不设置的话 切换界面 会执行动画
        overridePendingTransition(0,0);
        finish();
        overridePendingTransition(0,0);//退出时候的动画
    }