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異步加載怎么開啟多線程？

我發(fā)現(xiàn)一個(gè)問題，使用異步加載圖片是單線程，不能同時(shí)加載多張圖片，而且必須要等前一個(gè)圖片加載完后才能開始加載后面一張，影響速度；而用多線程的話，多張圖片基本上都是同時(shí)加載出來的，速度效率快很多。那么問題來了，在異步加載中怎么使用多線程？

刻骨銘心__

2016-09-26

源自：Android必學(xué)-異步加載

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XhstormR 回答被采納 +3 積分
2016-09-26

public?View?getView(int?position,?View?convertView,?ViewGroup?parent)?{
????String?url?=?mData.get(position);
????ViewHolder?viewHolder?=?null;
????if?(convertView?==?null)?{
????????viewHolder?=?new?ViewHolder();
????????convertView?=?mInflater.inflate(R.layout.listview_item,?null);
????????viewHolder.imageView?=?(ImageView)?convertView.findViewById(R.id.iv_lv_item);
????????convertView.setTag(viewHolder);
????}?else?{
????????viewHolder?=?(ViewHolder)?convertView.getTag();
????}
????viewHolder.imageView.setTag(url);
????viewHolder.imageView.setImageResource(R.drawable.ic_launcher);
????mImageLoader.showImageByThread(viewHolder.imageView,?url);
????return?convertView;
}
?
?
?
private?class?ImgHolder?{
????public?Bitmap?bitmap;
????public?ImageView?imageView;
????public?String?url;
??
????public?ImgHolder(ImageView?iv,?Bitmap?bm,String?url)?{
????????this.imageView?=?iv;
????????this.bitmap?=?bm;
????????this.url?=?url;
????}
}

public?void?showImageByThread(final?ImageView?imageView,?final?String?url)?{
?
????mHandler?=?new?Handler()?{
????????@Override
????????public?void?handleMessage(Message?msg)?{
????????????ImgHolder?holder?=?(ImgHolder)?msg.obj;
????????????if?(holder.imageView.getTag().equals(holder.url))?{
????????????????holder.imageView.setImageBitmap(holder.bitmap);
????????????}
????????}
????};
????new?Thread()?{
????????@Override
????????public?void?run()?{
????????????Bitmap?bitmap?=?getBitmapFromUrl(url);
????????????Message?message?=?Message.obtain();
????????????message.obj?=?new?ImgHolder(imageView,?bitmap,?url);
????????????mHandler.sendMessage(message);
????????}
????}.start();
}

這是老師的代碼。