Question

这是第二个类，它为我使用的图像提供格式

public ViewPagerAdapter(Activity activity, String[] images) {
    this.activity = activity;
    this.images = images;


}

@Override
public int getCount() {
    return images.length;
}

@Override
public boolean isViewFromObject(@NonNull View view, @NonNull Object object) {
    return view==object;
}


@Override
public Object instantiateItem(ViewGroup container, int position) {
    inflater =(LayoutInflater)activity.getApplicationContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    View itemView= inflater.inflate(R.layout.viewpager_item,container,false);

    ImageView image;
    DisplayMetrics dis = new DisplayMetrics();
    activity.getWindowManager().getDefaultDisplay().getMetrics(dis);
    int height = dis.heightPixels;
    int width = dis.widthPixels;
    image.setMinimumHeight(height);
    image.setMinimumWidth(width);

    try {
        Picasso.with(activity.getApplicationContext())
                .load(images[position])
                .placeholder(R.mipmap.ic_launcher)
                .error(R.mipmap.ic_launcher)
                .into(image);

    }
    catch (Exception ex) {
    }
    container.addView(itemView);
    return itemView;


}

@Override
public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {
    ((ViewPager) container).removeView((View)object);
}}`

这是主要的课程

    ViewPager viewPager;
ViewPagerAdapter adapter;
private String [] images = {




};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_search);

    viewPager = (ViewPager)findViewById(R.id.viewpager);
    adapter = new ViewPagerAdapter(Search.this,images);
    viewPager.setAdapter(adapter);




}}

我正在关注这个youtube教程，我有相同的代码，但我的代码不起作用https://www.youtube.com/watch?v=SX8l9vv-N_4
如果强迫我将变量声明为null，但在视频中没有。

Answer 1

你忘记了findViewById image = findViewById(...);

为什么它会给出错误“初始化变量图像”？但是当我初始化应用程序崩溃时

1 个答案: