參考两篇文章：http://blog.csdn.net/watermusicyes/article/details/47392949

    http://blog.csdn.net/droyon/article/details/21275797

recreate能够使用在日间/夜间模式的切换，那么调用recreate()函数将会运行哪些方法呢？

代码：

public class MainActivity extends FragmentActivity implements OnClickListener {

	private Button btn;

	private int mTheme;

	private String THEME = "theme";

	@Override

	protected void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);

		if (savedInstanceState != null) {

			mTheme = savedInstanceState.getInt(THEME);

			switchTheme(mTheme);

		}

		setContentView(R.layout.activity_main);

		btn = (Button) findViewById(R.id.btn);

		btn.setOnClickListener(this);

		Log.e(MainActivity.class.getName(), "onCreate");

	}

	@Override

    protected void onSaveInstanceState(Bundle savedInstanceState) {

        super.onSaveInstanceState(savedInstanceState);

        Log.e(MainActivity.class.getName(), "onSaveInstanceState");

        savedInstanceState.putInt(THEME, mTheme);

    } 

	@Override

	protected void onRestoreInstanceState(Bundle savedInstanceState) {

		super.onRestoreInstanceState(savedInstanceState);

		Log.e(MainActivity.class.getName(), "onRestoreInstanceState");

	}

	@Override

	protected void onStart() {

		super.onStart();

		Log.e(MainActivity.class.getName(), "onStart");

	}

	@Override

	protected void onResume() {

		super.onResume();

		Log.e(MainActivity.class.getName(), "onResume");

	}

	private void switchTheme(int theme) {

		switch (mTheme) {

		case android.R.style.Theme_Holo_Light:

			mTheme = android.R.style.Theme_Black_NoTitleBar;

			break;

		case android.R.style.Theme_Black_NoTitleBar:

			mTheme = android.R.style.Theme_Holo_Light;

			break;

		default:

			mTheme = android.R.style.Theme_Holo_Light;

			break;

		}

		setTheme(mTheme);

	}

	@SuppressLint("NewApi")

	@Override

	public void onClick(View v) {

		recreate();

	}

}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:paddingBottom="@dimen/activity_vertical_margin"

    android:paddingLeft="@dimen/activity_horizontal_margin"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    tools:context="com.example.testandroid.MainActivity" >

    <Button

        android:id="@+id/btn"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:text="recreate" />

</RelativeLayout>

点击recreatebutton能够看到打印相关的信息：

watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center" alt="" />

能够看到这里调用recreate方法会比正常启动Activity多调用了onSaveInstanceState和onRestoreInstanceState。而且onSaveInstanceState在onCreate方法之前调用。

注意：（1）

if (savedInstanceState != null) {

			mTheme = savedInstanceState.getInt(THEME);

			switchTheme(mTheme);

		}

这部分代码要在setContentView(R.layout.activity_main)代码之前调用，否则改变不了主题。

（2）recreate()方法是在Android3.0引入的，所以假设在3.0之前使用会出现错误。例如以下图所看到的：

watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center" alt="" />