Activity重新创建之recreate_android recreate

Android在3.0之后，Activity引入了新的一个方法：recreate()，从字面意思就知道是重新创建Activity的，3.0+版本才可以使用。

/**
 * 调用recreate方法重新创建Activity会比正常启动Activity多调用了onSaveInstanceState
 * ()和onRestoreInstanceState()两个方法，onSaveInstanceState()会在onCreate方法之前调用。
 * 所以可以在onCreate()方法中获取onSaveInstanceState()保存的Theme数据
 * 
 * @description：
 * @author ldm
 * @date 2016-4-19 上午9:34:49
 */
public class MainActivity extends Activity implements OnClickListener {
    private Button recreate;
    private int mCurrentTheme;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // 从onSaveInstanceState(Bundle outState)方法中保存的数据取出Theme
        if (savedInstanceState != null) {
            mCurrentTheme = savedInstanceState.getInt("mCurrentTheme");
            // 切换Activity的Theme
            switch (mCurrentTheme) {
            case android.R.style.Theme_Holo_Light:
                mCurrentTheme = android.R.style.Theme_Holo_Dialog;
                break;
            case android.R.style.Theme_Holo_Dialog:
                mCurrentTheme = android.R.style.Theme_Holo;
                break;
            default:
                mCurrentTheme = android.R.style.Theme_Holo_Light;
                break;
            }
            setTheme(mCurrentTheme);
        }

        setContentView(R.layout.activity_main);
        this.recreate = (Button) findViewById(R.id.recreate);
        this.recreate.setOnClickListener(this);
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putInt("mCurrentTheme", mCurrentTheme);// 把当前Theme保存
    }

    @Override
    public void onClick(View v) {
        recreate();// 直接调用Activity的recreate()方法重启Activity
    }
}
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