Question

我在纵向模式下有一个视图寻呼机。在横向模式下，我有完全不同的布局。从风景回到肖像后，我想看看最后看到的viewpager页面。但总是第一页在屏幕上。

以下是我的代码：

public class MainActivity extends FragmentActivity {

    public static ViewPager pager=null;
    public static FragmentAdapter adapter;
    PageIndicator mIndicator;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_delict);
        if(getResources().getConfiguration().orientation==Configuration.ORIENTATION_PORTRAIT){
                pager = (ViewPager) findViewById(R.id.pager);
                adapter = new FragmentAdapter(getSupportFragmentManager());
                pager.setOffscreenPageLimit(4);
                pager.setAdapter(adapter);
                mIndicator = (CirclePageIndicator)findViewById(R.id.indicator);
                mIndicator.setViewPager(pager);
                mIndicator.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
                    @Override
                    public void onPageSelected(int position) {
                        Toast.makeText(MainActivity.this, "Changed to page " + position, Toast.LENGTH_SHORT).show();
                    }

                    @Override
                    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
                    }

                    @Override
                    public void onPageScrollStateChanged(int state) {
                    }
                });
            }

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.delict, menu);
        return true;
    }
    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        if(getResources().getConfiguration().orientation==Configuration.ORIENTATION_PORTRAIT){
            if(pager!=null){
                outState.putInt("PAGE", pager.getCurrentItem());
            }
        }

    }
    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);
        if(pager!=null){
         pager.setCurrentItem(savedInstanceState.getInt("PAGE"));
        }
    }
}

Answer 1

我目前没有打开IDE，因此可能需要进行语法更正：

@Override
protected void onSaveInstanceState(Bundle bundle) {
  super.onSaveInstanceState(bundle);
  bundle.putInt("currentItem", pager.getCurrentItem());
}

public void onCreate(Bundle savedInstanceState) {

    ...

    if (savedInstanceState != null) {
        pager.setCurrentItem(savedInstanceState.getInt("currentItem", 0));
    }
}

保存查看寻呼机的当前页面

1 个答案: