Question

我希望能够在Android上预先加载动态内容的下一个ViewPager页面。在创建视图后，我将视图添加到视图中。

@Override
public Object instantiateItem(ViewGroup collection, int position) {
    LayoutInflater inflater = (LayoutInflater) collection.getContext()
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    View view = inflater.inflate(R.layout.test_layout, null);
    view.setTag("rel" + position);
    collection.addView(view, 0);
    return view;
}

如果我尝试使用findViewWithTag("rel" + (view1.getCurrentItem() + 1));获取下一个视图，则会返回null。那么，我怎样才能获得下一个视图，或者手动充气呢？

Answer 1

尝试使用setOffscreenPageLimit(int limit)类的ViewPager方法。

Answer 2

在进入下一个位置之前调用getItem方法，这样你就可以在getInstance中传递你想要的任何动态数据

私有类MyPagerAdapter扩展了FragmentPagerAdapter {

    public MyPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int pos) {
        switch(pos) {

        case 0: return FirstFragment.newInstance("FirstFragment, Instance 1");
        case 1: return SecondFragment.newInstance("SecondFragment, Instance 1");
        case 2: return ThirdFragment.newInstance("ThirdFragment, Instance 1");
        case 3: return ThirdFragment.newInstance("ThirdFragment, Instance 2");
        case 4: return ThirdFragment.newInstance("ThirdFragment, Instance 3");
        default: return ThirdFragment.newInstance("ThirdFragment, Default");
        }
    }

    @Override
    public int getCount() {
        return 5;
    }       
}

公共类FirstFragment扩展了Fragment {

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View v = inflater.inflate(R.layout.first_frag, container, false);

    TextView tv = (TextView) v.findViewById(R.id.tvFragFirst);
    tv.setText(getArguments().getString("msg"));

    return v;
}

public static FirstFragment newInstance(String text) {

    FirstFragment f = new FirstFragment();
    Bundle b = new Bundle();
    b.putString("msg", text);

    f.setArguments(b);

    return f;
}

}

ViewPager如何预加载下一个视图Android

2 个答案: