java - 使用来自 URL 的图像创建 GridView

Question

我一刻都不想离开这里，哈

我在使用 picasso 将 url 中的图像加载到 gridview 时遇到了一些问题

我一直在关注这里的教程

http://developer.android.com/guide/topics/ui/layout/gridview.html#example

本教程很容易理解，但是它不处理位图图像，所以我尝试使用自定义图像适配器中的 imageView 引用将图像从 url 应用到 ImageView

预期的结果是同一张图片在屏幕上重复多次，但应用程序加载正常，但图片是空白的。物体在那里是因为在触摸屏幕时可以看到它们。

主要 Activity 类

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.GridView;
import android.widget.Toast;


public class MainActivity extends Activity {

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        //Call JSON
        // make call to json to get the information to display



        GridView gridview = (GridView) findViewById(R.id.gridview);
        gridview.setAdapter(new ImageAdapter(this));

        gridview.setOnItemClickListener(new OnItemClickListener() {
            public void onItemClick(AdapterView<?> parent, View v,
                                    int position, long id) {
                Toast.makeText(MainActivity.this, "" + position,
                        Toast.LENGTH_SHORT).show();
            }
        });
    }


}

图像适配器类

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

import com.squareup.picasso.Picasso;

public class ImageAdapter extends BaseAdapter {
    private Context mContext;

    public ImageAdapter(Context c) {
        mContext = c;
    }

    public int getCount() {
        return mThumbIds.length;
    }

    public Object getItem(int position) {
        return null;
    }

    public long getItemId(int position) {
        return 0;
    }

    // create a new ImageView for each item referenced by the Adapter
    public View getView(int position, View convertView, ViewGroup parent) {
        ImageView imageView;
        if (convertView == null) {
            // if it's not recycled, initialize some attributes
            imageView = new ImageView(mContext);
            imageView.setLayoutParams(new GridView.LayoutParams(200, 200));
         //   imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
         //   imageView.setPadding(1, 1, 1, 1);
        } else {
            imageView = (ImageView) convertView;
        }

        // Picasso.with(this.mContext).load("http://www.bathchronicle.co.uk/user/lw-avatar/3541022/profileSmall1407142824456.png").into(imageView);

        String url = "http://www.500kgiveaway.co.uk/upload/images/1430572021716.jpg";

        Picasso.with(this.mContext).load(url)
                .resize(100, 100).into(imageView);

 //       imageView.setImageResource(mThumbIds[position]);


        return imageView;
    }

    // references to our images
    private Integer[] mThumbIds = {
            R.drawable.sample_2, R.drawable.sample_3,
            R.drawable.sample_4, R.drawable.sample_5,
            R.drawable.sample_6, R.drawable.sample_7,
            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,
            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
    };
}

Answer 1

我运行了你的代码。您可能忘记添加此权限，其余看起来没问题。

<uses-permission android:name="android.permission.INTERNET"/>

从互联网上下载图片需要它。

您还可以启用日志记录以查看幕后发生的情况。

Picasso.with(this.mContext).setLoggingEnabled(true);