引导页,第二次登陆消失

public class MainActivity extends Activity {


private ViewPager viewpage;
private Button enter;
private ArrayList<Image> list = new ArrayList<Image>();
private SharedPreferences sp;


@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// 获取sharedperfences对象
sp = getSharedPreferences("config", MODE_PRIVATE);
// 去文件中获取是否进来过信息
boolean flag = sp.getBoolean("flag", false);
// 如果用户点击过按钮,会进来一个true的值,直接跳转
if (flag) {
enterDeal();
return;
}
// 获取控件id
viewpage = (ViewPager) findViewById(R.id.viewpage);
enter = (Button) findViewById(R.id.enter);
addpic();
}


// 向集合添加图片
public void addpic() {
list.add(new Image(R.drawable.a));
list.add(new Image(R.drawable.b));
list.add(new Image(R.drawable.c));
list.add(new Image(R.drawable.d));
list.add(new Image(R.drawable.e));
viewpage.setAdapter(new MyPageAdapter(list, MainActivity.this));
// viewpage的监听事件
viewpage.setOnPageChangeListener(vp);
// 进入的点击事件
enter.setOnClickListener(et);
}


// 进入的点击事件
OnClickListener et = new OnClickListener() {


@Override
public void onClick(View v) {


// 设置一个标记,说明我点击过引导页的进入按钮
Editor edit = sp.edit();
edit.putBoolean("flag", true);
edit.commit();


// 点击跳转
Intent intent = new Intent(MainActivity.this, First.class);
startActivity(intent);
finish();
}
};


// viewpage的监听事件
OnPageChangeListener vp = new OnPageChangeListener() {


@Override
public void onPageSelected(int postion) {


if (postion == list.size() - 1) {// 设置按钮显示
enter.setVisibility(View.VISIBLE);
} else {// 设置按钮隐藏
enter.setVisibility(View.GONE);
}
}


@Override
public void onPageScrolled(int arg0, float arg1, int arg2) {


}


@Override
public void onPageScrollStateChanged(int arg0) {


}
};


public void enterDeal() {
// 点击跳转
Intent intent = new Intent(MainActivity.this, First.class);
startActivity(intent);
finish();
}
}