{"id":955,"date":"2015-08-14T09:53:51","date_gmt":"2015-08-14T01:53:51","guid":{"rendered":"https:\/\/ai.zhousir.top\/?p=955"},"modified":"2015-08-14T10:29:19","modified_gmt":"2015-08-14T02:29:19","slug":"android%e5%8a%a0%e8%bd%bd%e7%bd%91%e7%bb%9c%e5%9b%be%e7%89%87","status":"publish","type":"post","link":"https:\/\/ai.zhousir.top\/?p=955","title":{"rendered":"Android\u52a0\u8f7d\u7f51\u7edc\u56fe\u7247"},"content":{"rendered":"

Android\u52a0\u8f7d\u7f51\u7edc\u56fe\u7247\u8d44\u6e90\u65b9\u5f0f\u548c\u52a0\u8f7d\u5b57\u7b26\u4e32\u8d44\u6e90\u7c7b\u5f0f\uff0c\u4e5f\u662f\u901a\u8fc7Http\u8fde\u63a5\u89e3\u6790\u8fd4\u56de\u7684\u5b57\u8282\u6d41InputStream\u5b9e\u73b0
\n<\/p>\n

[java]\/\/\u6784\u9020URL\u7c7b
\nURL url = new URL(httpUrl);
\n\/\/\u4eceurl\u4e2d\u5f97\u5230\u56fe\u7247\u8f93\u5165\u6d41
\nInputStream in = url.openStream();
\n\/\/\u4f7f\u7528BitmapFactory\u7c7b\u89e3\u6790\u6d41\u5f97\u5230Bitmap\u5bf9\u8c61
\nBitmap bitmap = BitmapFactory.decodeStream(in);[\/java]<\/p>\n

\u6ce8:InputStream in = url.openStream()
\n\u7b49\u4ef7\u4e8e
\nHttpURLConnection conn = (HttpURLConnection) url.openConnection();
\nInputStream is = conn.getInputStream();<\/p>\n

openStream()\u65b9\u6cd5\u5176\u5b9e\u662f\u5bf9\u4e0a\u9762\u4e24\u884c\u4ee3\u7801\u7684\u5c01\u88c5<\/p>\n

[java] \/**
\n * Equivalent to {@code openConnection().getInputStream(types)}.
\n *\/
\n public final InputStream openStream() throws IOException {
\n return openConnection().getInputStream();
\n}[\/java]<\/p>\n

\u63a5\u7740\u6211\u4eec\u6765\u5b9e\u73b0\u4e00\u4e2a\u7f51\u7edc\u52a0\u8f7d\u5355\u5f20\u56fe\u7247\u5b9e\u4f8b
\n\u9996\u5148\u5b9a\u4e49\u4e00\u4e2a\u65b9\u6cd5\u6839\u636e\u56fe\u7247\u5730\u5740\u83b7\u53d6\u56fe\u7247<\/p>\n

[java]public Bitmap downLoadBitmap(String httpUrl) {
\n\t\tInputStream in = null;
\n\t\ttry {
\n\t\t\tURL url = new URL(httpUrl);
\n\t\t\tin = url.openStream();
\n\t\t\tBitmap bitmap = BitmapFactory.decodeStream(in);
\n\t\t\treturn bitmap;<\/p>\n

\t\t} catch (MalformedURLException e) {
\n\t\t\te.printStackTrace();
\n\t\t} catch (IOException e) {
\n\t\t\te.printStackTrace();
\n\t\t} finally {
\n\t\t\tif (in != null) {
\n\t\t\t\ttry {
\n\t\t\t\t\tin.close();
\n\t\t\t\t} catch (IOException e) {
\n\t\t\t\t\te.printStackTrace();
\n\t\t\t\t}
\n\t\t\t}
\n\t\t}<\/p>\n

\t\treturn null;
\n\t}[\/java]<\/p>\n

\u52a0\u8f7d\u7f51\u7edc\u56fe\u7247\u662f\u8017\u65f6\u64cd\u4f5c\u6211\u4eec\u9700\u8981\u5728\u5f02\u6b65\u4efb\u52a1\u4e2d\u8c03\u7528<\/p>\n

[java]
\nString httpUrl = "http:\/\/d.hiphotos.baidu.com\/image\/h%3D360\/sign=
\nba3bf5f839c79f3d90e1e2368aa1cdbc\/f636afc379310a55c01f6ef3b54543a9822610f9.jpg";<\/p>\n

\t\t\tnew AsyncTask<String, Void, Bitmap>() {
\n\t\t\t\tprotected void onPreExecute() {
\n\t\t\t\t\tmProgressBar.setVisibility(View.VISIBLE);
\n\t\t\t\t}<\/p>\n

\t\t\t\t@Override
\n\t\t\t\tprotected Bitmap doInBackground(String… params) {
\n\t\t\t\t\tString httpUrl = params[0];
\n\t\t\t\t\tBitmap bitmap = downLoadBitmap(httpUrl);<\/p>\n

\t\t\t\t\treturn bitmap;
\n\t\t\t\t}<\/p>\n

\t\t\t\t@Override
\n\t\t\t\tprotected void onPostExecute(Bitmap result) {
\n\t\t\t\t\tmProgressBar.setVisibility(View.GONE);
\n\t\t\t\t\tif (result != null)
\n\t\t\t\t\t\tmShowImg.setImageBitmap(result);<\/p>\n

\t\t\t\t}
\n\t\t\t}.execute(httpUrl);[\/java]<\/p>\n

\u754c\u9762\u90e8\u4efd\u4f7f\u7528imageView\u63a7\u4ef6\uff0cProgressBar\u663e\u793a\u52a0\u8f7d\u4e2d\u6548\u679c\u5982\u4e0b
\n\"imageloader1\"<\/a><\/p>\n

\u63a5\u7740\u6211\u4eec\u5728\u6765\u770b\u4e0b\u5b9e\u73b0\u591a\u56fe\u52a0\u8f7d\u64cd\u4f5c<\/strong>
\n\u83b7\u53d6\u56fe\u7247\u8d44\u6e90\u65b9\u5f0f\u548c\u5355\u5f20\u56fe\u7247\u4e00\u6837\uff0c\u663e\u793a\u63a7\u4ef6\u6211\u4eec\u6362\u7528GridView.
\n\u4e3b\u8981\u4ee3\u7801\u5982\u4e0b
\n[java]@Override
\npublic View getView(int position, View convertView, ViewGroup parent) {<\/p>\n

\tfinal ImageView loaderImageView;<\/p>\n

\tif (convertView == null) {
\n\t\tconvertView = mInflater.inflate(R.layout.item_my_gridview_layout, null);<\/p>\n

\t\tloaderImageView = (ImageView) convertView.findViewById(R.id.my_gridview_img);
\n\t\tconvertView.setTag(loaderImageView);
\n\t} else {
\n\t\tloaderImageView = (ImageView) convertView.getTag();
\n\t}<\/p>\n

\tString itemUrl = (String) getItem(position);<\/p>\n

\tnew AsyncTask<String, Void, Bitmap>() {<\/p>\n

\t\t@Override
\n\t\tprotected Bitmap doInBackground(String… params) {
\n\t\t\tString httpUrl = params[0];
\n\t\t\t\/\/\u6839\u636ehttpUrl\u5730\u5740\u52a0\u8f7d\u7f51\u7edc\u56fe\u7247
\n\t\t\t\tBitmap bitmap = downLoadBitmap(httpUrl);
\n\t\t\t\treturn bitmap;
\n\t\t\t}<\/p>\n

\t\t\t@Override
\n\t\t\tprotected void onPostExecute(Bitmap result) {<\/p>\n

\t\t\t\tif (result != null)
\n\t\t\t\t\tloaderImageView.setImageBitmap(result);<\/p>\n

\t\t\t}
\n\t\t}.execute(itemUrl);<\/p>\n

\t\treturn convertView;
\n\t}<\/p>\n

}[\/java]<\/p>\n

\u6548\u679c\u5982\u4e0b:
\n\"imageloader2\"<\/a><\/p>\n

\u5c06AsyncTask\u653e\u5230\u9002\u914d\u5668getView\u65b9\u6cd5\u83b7\u53d6\u56fe\u7247\u4e00\u5c4f\u7684\u65f6\u5019\u611f\u89c9\u4e0d\u5230\u95ee\u9898\uff0c\u5f53\u6211\u4eec\u56fe\u7247\u5f88\u591a\u65f6\uff0c\u4e0a\u4e0b\u6eda\u52a8\uff0c\u8fd9\u65f6\u4f1a\u53d1\u73b0\u56fe\u7247\u9519\u4f4d\u73b0\u8c61.
\n\u8fd9\u662f\u56e0\u4e3a\u4e0a\u4e0b\u6eda\u52a8\u65f6\u4f1a\u4e0d\u4f46\u91cd\u590d\u8c03\u7528getView\u65b9\u6cd5\u542f\u52a8AsyncTask.\u4e3a\u4e86\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\u6211\u4eec\u53ef\u4ee5\u5c06AsyncTask\u8fdb\u884c\u4fdd\u5b58\uff0c\u6839\u636eUrl\u6765\u63a7\u5236\u662f\u5426\u542f\u52a8AsyncTask,\u5177\u4f53\u4ee3\u7801\u5982\u4e0b:
\n[java]
\npublic void loadBitmap(Resources res,String imageUrl, ImageView imageView, int resId) {
\n\tif (cancelPotentialWork(imageUrl, imageView)) {
\n\t\tBitmapWorkerTask task = new BitmapWorkerTask(imageView);<\/p>\n

\t\tAsyncDrawable asyncDrawable = new AsyncDrawable(res,
\n\t\t\t\tBitmapFactory.decodeResource(res, resId), task);
\n\t\timageView.setImageDrawable(asyncDrawable);<\/p>\n

\t\ttask.execute(imageUrl);<\/p>\n

\t}<\/p>\n

}<\/p>\n

public static boolean cancelPotentialWork(String imageUrl,
\n\t\tImageView imageView) {
\n\tfinal BitmapWorkerTask bitmapWorkerTask = getBitmapWorkerTask(imageView);<\/p>\n

\tif (bitmapWorkerTask != null) {
\n\t\tfinal String bitmapData = bitmapWorkerTask.imageUrl;
\n\t\tif (!bitmapData.equals(imageUrl)) {
\n\t\t\t\/\/ Cancel previous task
\n\t\t\tbitmapWorkerTask.cancel(true);
\n\t\t} else {
\n\t\t\t\/\/ The same work is already in progress
\n\t\t\treturn false;
\n\t\t}
\n\t}
\n\t\/\/ No task associated with the ImageView, or an existing task was
\n\t\/\/ cancelled
\n\treturn true;
\n}<\/p>\n

private static BitmapWorkerTask getBitmapWorkerTask(ImageView imageView) {
\n\tif (imageView != null) {
\n\t\tfinal Drawable drawable = imageView.getDrawable();
\n\t\tif (drawable instanceof AsyncDrawable) {
\n\t\t\tfinal AsyncDrawable asyncDrawable = (AsyncDrawable) drawable;
\n\t\t\treturn asyncDrawable.getBitmapWorkerTask();
\n\t\t}
\n\t}
\n\treturn null;
\n}<\/p>\n

\/**
\n * \u521b\u5efa\u4e00\u4e2a\u4e13\u7528\u7684Drawable\u7684\u5b50\u7c7b\u6765\u50a8\u5b58\u8fd4\u56de\u5de5\u4f5c\u4efb\u52a1\u7684\u5f15\u7528\u3002\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0c\u5f53\u4efb\u52a1\u5b8c\u6210\u65f6BitmapDrawable\u4f1a\u88ab\u4f7f\u7528
\n *
\n *\/
\nstatic class AsyncDrawable extends BitmapDrawable {
\n\tprivate final WeakReference<BitmapWorkerTask> bitmapWorkerTaskReference;<\/p>\n

\tpublic AsyncDrawable(Resources res, Bitmap bitmap,
\n\t\t\tBitmapWorkerTask bitmapWorkerTask) {
\n\t\tsuper(res, bitmap);
\n\t\tbitmapWorkerTaskReference = new WeakReference<BitmapWorkerTask>(
\n\t\t\t\tbitmapWorkerTask);
\n\t}<\/p>\n

\tpublic BitmapWorkerTask getBitmapWorkerTask() {
\n\t\treturn (BitmapWorkerTask) bitmapWorkerTaskReference.get();
\n\t}
\n}<\/p>\n

class BitmapWorkerTask extends AsyncTask<String, Void, Bitmap> {
\n\tprivate final WeakReference<ImageView> imageViewReference;
\n\tprivate String imageUrl = "";<\/p>\n

\tpublic BitmapWorkerTask(ImageView imageView) {
\n\t\t\/\/ Use a WeakReference to ensure the ImageView can be garbage
\n\t\t\/\/ collected
\n\t\timageViewReference = new WeakReference<ImageView>(imageView);
\n\t}<\/p>\n

\t\/\/ Decode image in background.
\n\t@Override
\n\tprotected Bitmap doInBackground(String… params) {
\n\t\timageUrl = params[0];
\n\t\treturn downLoadBitmap(imageUrl);
\n\t}<\/p>\n

\t\/\/ Once complete, see if ImageView is still around and set bitmap.
\n\t@Override
\n\tprotected void onPostExecute(Bitmap bitmap) {
\n\t\tif (isCancelled()) {
\n\t\t\tbitmap = null;
\n\t\t}<\/p>\n

\t\tif (imageViewReference != null && bitmap != null) {
\n\t\t\tfinal ImageView imageView = (ImageView) imageViewReference
\n\t\t\t\t\t.get();
\n\t\t\tfinal BitmapWorkerTask bitmapWorkerTask = getBitmapWorkerTask(imageView);
\n\t\t\tif (this == bitmapWorkerTask && imageView != null) {
\n\t\t\t\timageView.setImageBitmap(bitmap);
\n\t\t\t}
\n\t\t}
\n\t}
\n}
\n[\/java]<\/p>\n","protected":false},"excerpt":{"rendered":"

Android\u52a0\u8f7d\u7f51\u7edc\u56fe\u7247\u8d44\u6e90\u65b9\u5f0f\u548c\u52a0\u8f7d\u5b57\u7b26\u4e32\u8d44\u6e90\u7c7b\u5f0f\uff0c\u4e5f\u662f\u901a\u8fc7Http\u8fde\u63a5\u89e3\u6790\u8fd4\u56de\u7684\u5b57\u8282\u6d41InputStre […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[8],"tags":[],"_links":{"self":[{"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/posts\/955"}],"collection":[{"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=955"}],"version-history":[{"count":5,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/posts\/955\/revisions"}],"predecessor-version":[{"id":963,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/posts\/955\/revisions\/963"}],"wp:attachment":[{"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=955"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=955"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=955"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}