Android实现ListView异步加载图片

核心提示：viewCache = (ViewCache) rowView.getTag();}ImageAndText imageAndText = getItem(position);// Load the image and set it on the ImageViewString imageUrl = imageAndT

viewCache = (ViewCache) rowView.getTag();

}

ImageAndText imageAndText = getItem(position);

// Load the image and set it on the ImageView

String imageUrl = imageAndText.getImageUrl();

ImageView imageView = viewCache.getImageView();

imageView.setTag(imageUrl);

Drawable cachedImage = asyncImageLoader.loadDrawable(imageUrl, new ImageCallback() {

public void imageLoaded(Drawable imageDrawable, String imageUrl) {

ImageView imageViewByTag = (ImageView) listView.findViewWithTag(imageUrl);

if (imageViewByTag != null) {

imageViewByTag.setImageDrawable(imageDrawable);

}

}

});

if (cachedImage == null) {

imageView.setImageResource(R.drawable.default_image);

}else{

imageView.setImageDrawable(cachedImage);

}

// Set the text on the TextView

TextView textView = viewCache.getTextView();

textView.setText(imageAndText.getText());

return rowView;

}

}

ImageAndTextListAdapter是实现ListView的Adapter，里面有个技巧就是 imageView.setTag(imageUrl)，setTag是存储数据的，这样是为了保证在回调函数时，listview去更新自己对应 item,大家仔细阅读就知道了。

最后贴出布局文件：

Xml代码

< ?xml version="1.0" encoding="utf-8"?>

< LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:orientation="horizontal"

android:layout_width="fill_parent"

android:layout_height="wrap_content">

< ImageView android:id="@+id/image"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

/>

< TextView android:id="@+id/text"

android:layout_width="wrap_content"

android:layout_height="wrap_content"/>

< /LinearLayout>