fragment 适配器构造函数中的 Android gridview 丢失

Question

我正在尝试实现图像网格。我通过引用这个 link. 在 Activity 中做到了这一点现在，如果我尝试在扩展 Fragment 的类中实现同样的事情，我已经做到了这一点

package com.example.emergency1;

import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.WebView.FindListener;
import android.widget.GridView;

public class City1 extends Fragment {


    public static Fragment newInstance(Context context) {
        City1 f = new City1();
        return f;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
        ViewGroup root = (ViewGroup) inflater.inflate(R.layout.city1, null);
        GridView gv1=(GridView)getView().findViewById(R.id.gridview);
        gv1.setAdapter(new ImageAdapter(this));
        return root;
    }

}

和适配器

package com.example.emergency1;

import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;

public class ImageAdapter extends BaseAdapter {

    private Context ctx;

    public ImageAdapter(Context c)
    {
        ctx=c;
    }
    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return pics.length;
    }

    @Override
    public Object getItem(int position) {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub
        ImageView iv;
        if (convertView == null) {  // if it's not recycled, initialize some attributes
            iv = new ImageView(ctx);
            iv.setLayoutParams(new GridView.LayoutParams(350,350));
            iv.setScaleType(ImageView.ScaleType.CENTER_CROP);
            iv.setPadding(8, 8, 8, 8);
        } else {
            iv = (ImageView) convertView;
        }

        iv.setImageResource(pics[position]);
        return iv;

    }

    private Integer[] pics={
            R.drawable.sample_0,R.drawable.sample_1,
            R.drawable.sample_2,R.drawable.sample_3,
            R.drawable.sample_4,R.drawable.sample_5,
            R.drawable.sample_6,R.drawable.sample_7
    };
    }

这里，我在线上报错

gv1.setAdapter(new ImageAdapter(this));

因为我在适配器类中没有相应的构造函数。我该如何解决这个问题。您是否也可以将我重定向到某个链接，在那里我可以了解有关如何在 fragment 中实现 Activity UI 元素的更多信息？谢谢

Answer 1

使用

     gv1.setAdapter(new ImageAdapter(getActivity()));

而不是这个

     gv1.setAdapter(new ImageAdapter(this)); 

您需要传递 Activity 上下文。

还有这个

   GridView gv1=(GridView)getView().findViewById(R.id.gridview);

应该是

   GridView gv1=(GridView)root.findViewById(R.id.gridview);