ListView加载网络图片--------闪图问题解决

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ListView解决网络图片闪图问题

闪图问题根本原因是网络图片还没缓存下来就呈现，出现异步错误。

解决的方法也就是让网络图片先缓存下来，然后再呈现出来

一种方法是导入一个SmartImageView类库，然后调用setImageUrl(url)方法

holder.mIvHead.setImageUrl(user.headImg);

url参数是一个字符串路径

具体代码

public View getView(int position, View view, ViewGroup parent) {ViewHolder holder = null;if (view == null) {view = View.inflate(context, R.layout.msg_list_item, null);holder = new ViewHolder();holder.mIvHead = (SmartImageView) view.findViewById(R.id.ivHead);holder.mTvName = (TextView) view.findViewById(R.id.tvName);view.setTag(holder);} else {holder = (ViewHolder) view.getTag();}User user = userList.get(position);holder.mTvName.setText(user.name);holder.mIvHead.setImageUrl(user.headImg);return view;}

另一种方法是添加一个Picasso jar包

加上一句代码

Picasso.with(context).load(user.headImg).into(holder.mIvHead);

具体代码

public View getView(int position, View view, ViewGroup parent) {ViewHolder holder = null;if (view == null) {view = View.inflate(context, R.layout.msg_list_item, null);holder = new ViewHolder();holder.mIvHead = (ImageView) view.findViewById(R.id.ivHead);holder.mTvName = (TextView) view.findViewById(R.id.tvName);view.setTag(holder);} else {holder = (ViewHolder) view.getTag();}// TextView mTvName = (TextView) view.findViewById(R.id.tvName);// mIvHead = (ImageView) view.findViewById(R.id.ivHead);User user = userList.get(position);holder.mTvName.setText(user.name);Picasso.with(context).load(user.headImg).into(holder.mIvHead);return view;}

以上两种问题都可以解决闪图问题，或者自己写，先把图片缓存下来，然后再做呈现工作。

第一次获得的网络请求的图片写到内存中去

public static Bitmap getImageHttpClientGet(String path) throws Exception{// 缓存// ? 本地有没有？ /aaaa.jpgString localPath = CommonApplication.context.getCacheDir().getPath()+ "/" + UUID.nameUUIDFromBytes(path.getBytes()).toString();File file = new File(localPath);if (file.exists()){FileInputStream fileInputStream = new FileInputStream(file);return BitmapFactory.decodeStream(fileInputStream);} else{// 抽象类HttpClient client = new DefaultHttpClient();// 参数编码// path = URLEncoder.encode(path);// 创建请求 httpHttpGet httpGet = new HttpGet(path);HttpResponse response = client.execute(httpGet);int statusCode = response.getStatusLine().getStatusCode();if (statusCode == 200){HttpEntity entity = response.getEntity();InputStream in = entity.getContent();byte[] bytes = StreamUtil.getBytesByInputStream(in, localPath);Bitmap decodeByteArray = BitmapFactory.decodeByteArray(bytes,0, bytes.length);return decodeByteArray;}}return null;}

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