compile 'com.squareup.picasso:picasso:2.5.2'

Picasso.with(context).load("http://i.imgur.com/DvpvklR.png").into(imageView);

@Override
public voidgetView(intposition,View convertView,ViewGroup parent) {
  SquaredImageView view = (SquaredImageView) convertView;
  if(view ==null) {
    view =newSquaredImageView(context);
  }
  String url = getItem(position);
  Picasso.with(context).load(url).into(view);
}

Picasso.with(context)
    .load(url)
    .resize(50,50)
    .centerCrop()
    .into(imageView);

public class CropSquareTransformation implements Transformation {
  @Override
  public Bitmaptransform(Bitmap source) {
    int size = Math.min(source.getWidth(),source.getHeight());
    int x = (source.getWidth() - size) /2;
    int y = (source.getHeight() - size) /2;
    Bitmap result = Bitmap.createBitmap(source,x,y,size,size);
    if(result != source) {
      source.recycle();
    }
    return result;
  }
  @Override
  public String key() {
    return "square()";
  }
}

Picasso.with(context)
    .load(url)
    .placeholder(R.drawable.user_placeholder)
    .error(R.drawable.user_placeholder_error)
    .into(imageView);

Picasso.with(context).load(R.drawable.landing_screen).into(imageView1);
Picasso.with(context).load("file:///android_asset/DvpvklR.png").into(imageView2);
Picasso.with(context).load(newFile(...)).into(imageView3);

//表示菜类（经过烹调的蔬菜、蛋品、肉类等） 
public class Dish { 
 
  private String imgUrl; // 图片地址 
  private String name; // 菜名 
  private String price; // 菜价 
   
  public Dish(String imgUrl, String name, String price) { 
    this.imgUrl = imgUrl; 
    this.name = name; 
    this.price = price; 
  } 
 
  public String getImgUrl() { 
    return imgUrl; 
  } 
 
  public void setImgUrl(String imgUrl) { 
    this.imgUrl = imgUrl; 
  } 
 
  public String getName() { 
    return name; 
  } 
 
  public void setName(String name) { 
    this.name = name; 
  } 
 
  public String getPrice() { 
    return price; 
  } 
 
  public void setPrice(String price) { 
    this.price = price; 
  } 
 
} 

import java.util.ArrayList; 
 
import android.app.Activity; 
import android.os.Bundle; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.BaseAdapter; 
import android.widget.ImageView; 
import android.widget.ListView; 
import android.widget.TextView; 
 
import com.squareup.picasso.Picasso; 
 
public class MainActivity extends Activity { 
 
  private static final String BASE_URL = "http://img1.3lian.com/img2011/w1/106/85/"; 
   
  @Override 
  protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
 
    ArrayList<Dish> dishList = new ArrayList<Dish>(); 
 
    dishList.add(new Dish(BASE_URL + "42.jpg", "水煮鱼片", "38.00")); 
    dishList.add(new Dish(BASE_URL + "34.jpg", "小炒肉", "18.00")); 
    dishList.add(new Dish(BASE_URL + "37.jpg", "清炒时蔬", "15.00")); 
    dishList.add(new Dish(BASE_URL + "11.jpg", "金牌烤鸭", "36.00")); 
    dishList.add(new Dish(BASE_URL + "12.jpg", "粉丝肉煲", "20.00")); 
 
    ListView mListView = (ListView) this.findViewById(R.id.listview); 
    MainListViewAdapter adapter = new MainListViewAdapter(dishList); 
    mListView.setAdapter(adapter); 
  } 
 
  // ListView适配器 
  private class MainListViewAdapter extends BaseAdapter { 
 
    private ArrayList<Dish> dishList; 
 
    public MainListViewAdapter(ArrayList<Dish> list) { 
      this.dishList = list; 
    } 
 
    @Override 
    public int getCount() { 
      return dishList.size(); 
    } 
 
    @Override 
    public Object getItem(int position) { 
      return dishList.get(position); 
    } 
 
    @Override 
    public long getItemId(int position) { 
      return position; 
    } 
 
    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 
      ListViewItemHolder item = null; 
      if (convertView == null) { 
        convertView = LayoutInflater.from(MainActivity.this).inflate( 
            R.layout.main_listview_item, null); 
        item = new ListViewItemHolder(); 
        item.img_iv = (ImageView) convertView 
            .findViewById(R.id.imageView1); 
        item.name_textview = (TextView) convertView 
            .findViewById(R.id.textView1); 
        item.price_textview = (TextView) convertView 
            .findViewById(R.id.textView2); 
 
        convertView.setTag(item); 
      } else { 
        item = (ListViewItemHolder) convertView.getTag(); 
      } 
 
      Dish dish = dishList.get(position); 
 
      //这里就是异步加载网络图片的地方 
      Picasso.with(MainActivity.this).load(dish.getImgUrl()) 
          .into(item.img_iv); 
 
      item.name_textview.setText(dish.getName()); 
      item.price_textview.setText(dish.getPrice() + "元"); 
 
      return convertView; 
    } 
 
  } 
 
  // ListView的Item组件类 
  private class ListViewItemHolder { 
    ImageView img_iv; 
    TextView name_textview; 
    TextView price_textview; 
  } 
}