Android:在 ViewPager 中更改文本 [英] Android: Change text within ViewPager

问题描述

背景

我正在编写一个使用 ViewPager 并且运行良好的应用程序.我需要能够定位其中一种布局(xml 文件)并更新其上的 textviews 和 imageviews.我尝试使用v.findViewById"来放大视图和定位，这似乎是我研究的解决方案，但也许我将它放在正确的位置并且需要更好地向我解释.

I'm writing an app that uses the ViewPager and that's working nicely. I need to be able to target one of the layouts (xml file) and update the textviews and imageviews on it. I've tried inflating the view and targeting with "v.findViewById", which seems to be the solution from my research but maybe I'm putting it in the correct place and need it explained better to me.

我的代码(不尝试定位)

private ImageView circle;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.main);

    circle = (ImageView) findViewById(R.id.circles);

    MyPagerAdapter adapter = new MyPagerAdapter();
    ViewPager myPager = (ViewPager) findViewById(R.id.myViewPager);
    myPager.setAdapter(adapter);
    myPager.setCurrentItem(1);
    myPager.setOnPageChangeListener(new MyPageChangeListener()); 
}

private int focusedPage = 0;
private class MyPageChangeListener extends ViewPager.SimpleOnPageChangeListener {
    @Override
    public void onPageSelected(int position) {
        focusedPage = position;

        switch (focusedPage) {
            case 0: circle.setImageResource(R.drawable.circles1); break;
            case 1: circle.setImageResource(R.drawable.circles2); break;
            case 2: circle.setImageResource(R.drawable.circles3); break;
            case 3: circle.setImageResource(R.drawable.circles4); break;
        }
    }
}

private class MyPagerAdapter extends PagerAdapter {

    public int getCount() {
        return 4;
    }

    public Object instantiateItem(View collection, int position) {

        LayoutInflater inflater = (LayoutInflater) collection.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        int resId = 0;
        switch (position) {
            case 0:
                resId = R.layout.zip;
                break;
            case 1:
                resId = R.layout.forecast;
                break;
            case 2:
                resId = R.layout.settings;
                break;
            case 3:
                resId = R.layout.about;
                break;
        }

        View view = inflater.inflate(resId, null);

        ((ViewPager) collection).addView(view, 0);

        return view;
    }

    @Override
    public void destroyItem(View arg0, int arg1, Object arg2) {
        ((ViewPager) arg0).removeView((View) arg2);
    }

    @Override
    public boolean isViewFromObject(View arg0, Object arg1) {
        return arg0 == ((View) arg1);

    }

    @Override
    public Parcelable saveState() {
        return null;
    }
}

仅供参考:ImageViewcicle"是屏幕底部的 4 个圆圈的图像，会在页面更改时更新以显示您所在的屏幕.工作正常，只是想解释一下.

FYI: the ImageView "cicle" is an image of 4 circles at the bottom of the screen that gets updated on page change to show what screen you're on. working fine, just wanted to explain.

目标

在名为forecast"的布局上更新名为city"的文本视图.

Update a textview named "city" on the layout named "forecast".

提前感谢您的帮助！过了这个小障碍，应该会很轻松了.

Thanks in advance for any help! After this little hurdle, it should be easy sailing.

推荐答案

好吧，我不保证这可行，但我在 ViewPager 使用兼容性包时遇到了类似的问题，我用这个解决了这个问题:

Well I don't garantee that this works but I had a similar problem with ViewPager using compatibility pack that I solved using this:

在您的 instatiateItem 函数视图中，使用您的 resId 执行 setTag:

In your view at the instatiateItem function do a setTag with your resId:

view.setTag(resId);

那么当你需要改变你的城市"时:

Then when you need to change your "city" do:

View baseLayout = myPager.findViewWithTag(R.layout.forecast);
TextView city = (TextView) baseLayout.findViewById(R.id.city_id);

其中 R.id.city_id 是您的 TextView 的 id.

Where R.id.city_id is the id of your TextView.

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