缓存图像和显示 [英] Caching images and displaying
问题描述
您好现在面临的一个特殊问题中,我需要下载图片,并显示它们到的ListView
对应其特定的 TextView中的
。在code我已经成功地显示在 TextView中的
我需要显示,但我不知道如何来显示所有这些不同的图像旁边,我的文字意见,我的ListView
。
Hello Am facing a particular problem in which I need to download images and display them onto a ListView
corresponding to their particular TextView's
. The code I have is successfully displaying the The TextView's
I need to display but I don't know how to display all these different images next to my text views in my ListView
.
在在SO经历多个线程。顶端的答案是通过解决这个 1.懒惰名单 2.通用图像装载机
After going through many threads in SO. The top answers are to solve this by 1. Lazy List 2. Universal Image Loader
我已经经历了两个解决方案了。我下载的懒列表codeS中的URL被存储在一个阵列的硬盘codeD字符串。我想要做的就是动态地创建自己的字符串。它们存储到缓存中,并显示所有相应的图像。
I have gone through both the solutions. I downloaded Lazy List codes in which the URL's are hardcoded strings stored in an Array. What I would like to do is create my own Strings dynamically. Store them onto cache and display all the corresponding images.
下面是我的code:
public class Tools_ListItemActivity extends ListActivity
{
private Context context;
String s;
private static final String TAG_POSTS = "posts";
private static final String TAG_MDNAME = "mdname";
private static final String TAG_UTCOST = "utcost";
private static final String TAG_IIMG= "iimg";
JSONArray posts = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
s=getIntent().getExtras().getString("url");
new ProgressTask(Tools_ListItemActivity.this).execute();
}
@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
// TODO Auto-generated method stub
super.onListItemClick(l, v, position, id);
}
ArrayList<HashMap<String, String>> jsonlist = new ArrayList<HashMap<String, String>>();
ListView lv ;
private class ProgressTask extends AsyncTask<String, Void, Boolean> {
private ProgressDialog dialog;
public ProgressTask(ListActivity activity) {
Log.i("1", "Called");
context = activity;
dialog = new ProgressDialog(context);
}
/** progress dialog to show user that the backup is processing. */
/** application context. */
private Context context;
protected void onPreExecute() {
this.dialog.setMessage("Progress start");
this.dialog.show();
}
@Override
protected void onPostExecute(final Boolean success) {
if (dialog.isShowing()) {
dialog.dismiss();
}
ListAdapter adapter = new SimpleAdapter(context, jsonlist,
R.layout.activity_toolsitem, new String[] { TAG_IIMG, TAG_MDNAME, TAG_UTCOST }, new int[] {
R.id.imageViewUrl, R.id.mdname, R.id.utcost });
setListAdapter(adapter);
// selecting single ListView item
lv = getListView();
}
protected Boolean doInBackground(final String... args) {
JSONParser jParser = new JSONParser();
// getting JSON string from URL
JSONObject json = jParser.getJSONFromUrl(s);
try {
posts = json.getJSONArray(TAG_POSTS);
} catch (JSONException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try
{
// looping through All Contacts
for(int i = 0; i < posts.length(); i++){
JSONObject c = posts.getJSONObject(i);
// Storing each json item in variable
String mdname = c.getString(TAG_MDNAME);
String utcost= c.getString(TAG_UTCOST);
String iimg=c.getString(TAG_IIMG);
//Forming the Url of the image to be shown in the list view
String imageUrl="My_App_URL"+iimg;
/* try {
String imageUrl="My_App_URL"+iimg;
ImageView imageView = (ImageView)findViewById(R.id.imageViewUrl);
Bitmap bitmap = BitmapFactory.decodeStream((InputStream)new URL(imageUrl).getContent());
imageView.setImageBitmap(bitmap);
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} */
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(TAG_MDNAME, mdname);
map.put(TAG_UTCOST, utcost);
map.put(TAG_IIMG, iimg);
jsonlist.add(map);
} }catch (JSONException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
}
}
在这里,我已经调试并发现了 IMAGEURL
获取正确形成。 的Json
只返回的名称 JPG
,所以我它添加到URL并将其存储在 IMAGEURL
。另外两个textviews越来越正确分析和显示。如果有任何人可以帮助我在图像视图中显示的图像太那么这将是巨大的。谢谢。
Here i have debugged and found out that imageUrl
gets formed correctly. Json
only returns the name of the jpg
so i append that to the URL and Store it in imageUrl
. The other two textviews are getting properly parsed and displayed. If any one can help me out in displaying the images in the image view too then it would be great. Thanks.
更新: 我能解决我的具体问题与潘卡共享链接的帮助下(<一href="https://github.com/AndroidBegin/Android-JSON-Parse-Images-and-Texts-Tutorial">https://github.com/AndroidBegin/Android-JSON-Parse-Images-and-Texts-Tutorial)并通过Raghunandan共享的概念知识下面的人。请继续通过这些答案进行了详细的解释,也是实现延迟加载的。我的道歉不能够奖励一个答案与赏金,因为我是走了两天。
Update: I was able to solve my particular problem with the help of the link shared by Pankaj(https://github.com/AndroidBegin/Android-JSON-Parse-Images-and-Texts-Tutorial) and the concept knowledge shared by Raghunandan down below. Please go through these answers for a detailed explanation as well as implementation of Lazy loading. My apologies for not being able to reward an answer with bounty as i was away for two days.
推荐答案
使用通用ImageLoader的延迟加载。与URL的图像更换硬盘codeD网址。
Lazy loading using Universal Imageloader. Replace the hardcoded urls with url of images.
修改根据您的要求下面的
Modify the below according to your requirements
什么LazyList?。检查此链接了解详细信息。
What's LazyList?. Check this link for details.
MainActivity.java
MainActivity.java
public class MainActivity extends Activity {
private String[] mStrings={
"http://a3.twimg.com/profile_images/670625317/aam-logo-v3-twitter.png",
"http://a3.twimg.com/profile_images/740897825/AndroidCast-350_normal.png",
"http://a3.twimg.com/profile_images/121630227/Droid_normal.jpg",
"http://a1.twimg.com/profile_images/957149154/twitterhalf_normal.jpg",
"http://a1.twimg.com/profile_images/97470808/icon_normal.png",
"http://a3.twimg.com/profile_images/511790713/AG.png",
"http://a3.twimg.com/profile_images/956404323/androinica-avatar_normal.png",
"http://a1.twimg.com/profile_images/909231146/Android_Biz_Man_normal.png",
"http://a3.twimg.com/profile_images/72774055/AndroidHomme-LOGO_normal.jpg",
"http://a1.twimg.com/profile_images/349012784/android_logo_small_normal.jpg",
"http://a1.twimg.com/profile_images/841338368/ea-twitter-icon.png",
"http://a3.twimg.com/profile_images/64827025/android-wallpaper6_2560x160_normal.png",
"http://a3.twimg.com/profile_images/77641093/AndroidPlanet_normal.png",
"http://a1.twimg.com/profile_images/605536070/twitterProfilePhoto_normal.jpg",
"http://a1.twimg.com/profile_images/850960042/elandroidelibre-logo_300x300_normal.jpg",
"http://a1.twimg.com/profile_images/655119538/andbook.png",
"http://a3.twimg.com/profile_images/768060227/ap4u_normal.jpg",
"http://a1.twimg.com/profile_images/74724754/android_logo_normal.png",
"http://a3.twimg.com/profile_images/681537837/SmallAvatarx150_normal.png",
"http://a1.twimg.com/profile_images/63737974/2008-11-06_1637_normal.png",
"http://a3.twimg.com/profile_images/548410609/icon_8_73.png",
"http://a1.twimg.com/profile_images/612232882/nexusoneavatar_normal.jpg",
"http://a1.twimg.com/profile_images/213722080/Bugdroid-phone_normal.png",
"http://a1.twimg.com/profile_images/645523828/OT_icon_090918_android_normal.png",
"http://a3.twimg.com/profile_images/64827025/android-wallpaper6_2560x160_normal.png",
"http://a3.twimg.com/profile_images/77641093/AndroidPlanet.png",
"http://a1.twimg.com/profile_images/605536070/twitterProfilePhoto_normal.jpg",
"http://a1.twimg.com/profile_images/850960042/elandroidelibre-logo_300x300_normal.jpg",
"http://a1.twimg.com/profile_images/655119538/andbook_normal.png",
"http://a3.twimg.com/profile_images/511790713/AG_normal.png",
"http://a3.twimg.com/profile_images/956404323/androinica-avatar.png",
"http://a1.twimg.com/profile_images/909231146/Android_Biz_Man_normal.png",
"http://a3.twimg.com/profile_images/72774055/AndroidHomme-LOGO_normal.jpg",
"http://a1.twimg.com/profile_images/349012784/android_logo_small_normal.jpg",
"http://a1.twimg.com/profile_images/841338368/ea-twitter-icon_normal.png",
"http://a3.twimg.com/profile_images/64827025/android-wallpaper6_2560x160_normal.png",
"http://a3.twimg.com/profile_images/77641093/AndroidPlanet.png",
"http://a1.twimg.com/profile_images/605536070/twitterProfilePhoto_normal.jpg",
"http://a3.twimg.com/profile_images/64827025/android-wallpaper6_2560x160_normal.png",
"http://a3.twimg.com/profile_images/77641093/AndroidPlanet_normal.png",
"http://a1.twimg.com/profile_images/605536070/twitterProfilePhoto_normal.jpg",
"http://a1.twimg.com/profile_images/850960042/elandroidelibre-logo_300x300.jpg",
"http://a1.twimg.com/profile_images/655119538/andbook_normal.png",
"http://a3.twimg.com/profile_images/511790713/AG_normal.png",
"http://a3.twimg.com/profile_images/956404323/androinica-avatar_normal.png",
"http://a1.twimg.com/profile_images/909231146/Android_Biz_Man_normal.png",
"http://a3.twimg.com/profile_images/121630227/Droid.jpg",
"http://a1.twimg.com/profile_images/957149154/twitterhalf_normal.jpg",
"http://a1.twimg.com/profile_images/97470808/icon_normal.png",
"http://a3.twimg.com/profile_images/511790713/AG_normal.png",
"http://a3.twimg.com/profile_images/956404323/androinica-avatar_normal.png",
"http://a1.twimg.com/profile_images/909231146/Android_Biz_Man.png",
"http://a3.twimg.com/profile_images/72774055/AndroidHomme-LOGO_normal.jpg",
"http://a1.twimg.com/profile_images/349012784/android_logo_small_normal.jpg",
"http://a1.twimg.com/profile_images/841338368/ea-twitter-icon_normal.png",
"http://a3.twimg.com/profile_images/64827025/android-wallpaper6_2560x160_normal.png",
"http://a3.twimg.com/profile_images/77641093/AndroidPlanet.png",
"http://a3.twimg.com/profile_images/670625317/aam-logo-v3-twitter_normal.png",
"http://a3.twimg.com/profile_images/740897825/AndroidCast-350_normal.png",
"http://a3.twimg.com/profile_images/121630227/Droid_normal.jpg",
"http://a1.twimg.com/profile_images/957149154/twitterhalf_normal.jpg",
"http://a1.twimg.com/profile_images/97470808/icon.png",
"http://a3.twimg.com/profile_images/511790713/AG_normal.png",
"http://a3.twimg.com/profile_images/956404323/androinica-avatar_normal.png",
"http://a1.twimg.com/profile_images/909231146/Android_Biz_Man_normal.png",
"http://a3.twimg.com/profile_images/72774055/AndroidHomme-LOGO_normal.jpg",
"http://a1.twimg.com/profile_images/349012784/android_logo_small_normal.jpg",
"http://a1.twimg.com/profile_images/841338368/ea-twitter-icon.png",
"http://a3.twimg.com/profile_images/64827025/android-wallpaper6_2560x160_normal.png",
"http://a3.twimg.com/profile_images/77641093/AndroidPlanet_normal.png",
"http://a1.twimg.com/profile_images/605536070/twitterProfilePhoto_normal.jpg",
"http://a1.twimg.com/profile_images/850960042/elandroidelibre-logo_300x300_normal.jpg",
"http://a1.twimg.com/profile_images/655119538/andbook_normal.png",
"http://a3.twimg.com/profile_images/768060227/ap4u_normal.jpg",
"http://a1.twimg.com/profile_images/74724754/android_logo.png",
"http://a3.twimg.com/profile_images/681537837/SmallAvatarx150_normal.png",
"http://a1.twimg.com/profile_images/63737974/2008-11-06_1637_normal.png",
"http://a3.twimg.com/profile_images/548410609/icon_8_73_normal.png",
"http://a1.twimg.com/profile_images/612232882/nexusoneavatar_normal.jpg",
"http://a1.twimg.com/profile_images/213722080/Bugdroid-phone_normal.png",
"http://a1.twimg.com/profile_images/645523828/OT_icon_090918_android.png",
"http://a3.twimg.com/profile_images/64827025/android-wallpaper6_2560x160_normal.png",
"http://a3.twimg.com/profile_images/77641093/AndroidPlanet_normal.png",
"http://a1.twimg.com/profile_images/605536070/twitterProfilePhoto_normal.jpg",
"http://a1.twimg.com/profile_images/850960042/elandroidelibre-logo_300x300_normal.jpg",
"http://a1.twimg.com/profile_images/655119538/andbook.png",
"http://a3.twimg.com/profile_images/511790713/AG_normal.png",
"http://a3.twimg.com/profile_images/956404323/androinica-avatar_normal.png",
"http://a1.twimg.com/profile_images/909231146/Android_Biz_Man_normal.png",
"http://a3.twimg.com/profile_images/72774055/AndroidHomme-LOGO_normal.jpg",
"http://a1.twimg.com/profile_images/349012784/android_logo_small_normal.jpg",
"http://a1.twimg.com/profile_images/841338368/ea-twitter-icon.png",
"http://a3.twimg.com/profile_images/64827025/android-wallpaper6_2560x160_normal.png",
"http://a3.twimg.com/profile_images/77641093/AndroidPlanet_normal.png",
"http://a1.twimg.com/profile_images/605536070/twitterProfilePhoto_normal.jpg",
"http://a3.twimg.com/profile_images/64827025/android-wallpaper6_2560x160_normal.png",
"http://a3.twimg.com/profile_images/77641093/AndroidPlanet_normal.png",
"http://a1.twimg.com/profile_images/605536070/twitterProfilePhoto.jpg",
"http://a1.twimg.com/profile_images/850960042/elandroidelibre-logo_300x300_normal.jpg",
"http://a1.twimg.com/profile_images/655119538/andbook_normal.png",
"http://a3.twimg.com/profile_images/511790713/AG_normal.png",
"http://a3.twimg.com/profile_images/956404323/androinica-avatar_normal.png",
"http://a1.twimg.com/profile_images/909231146/Android_Biz_Man_normal.png",
"http://a3.twimg.com/profile_images/121630227/Droid_normal.jpg",
"http://a1.twimg.com/profile_images/957149154/twitterhalf.jpg",
"http://a1.twimg.com/profile_images/97470808/icon_normal.png",
"http://a3.twimg.com/profile_images/511790713/AG_normal.png",
"http://a3.twimg.com/profile_images/956404323/androinica-avatar_normal.png",
"http://a1.twimg.com/profile_images/909231146/Android_Biz_Man_normal.png",
"http://a3.twimg.com/profile_images/72774055/AndroidHomme-LOGO_normal.jpg",
"http://a1.twimg.com/profile_images/349012784/android_logo_small.jpg",
"http://a1.twimg.com/profile_images/841338368/ea-twitter-icon_normal.png",
"http://a3.twimg.com/profile_images/64827025/android-wallpaper6_2560x160_normal.png",
"http://a3.twimg.com/profile_images/77641093/AndroidPlanet_normal.png"
};
ListView lv;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
lv= (ListView) findViewById(R.id.lv);
lv.setAdapter(new LazyAdapter(this,mStrings));
}
}
activity_main.xml
activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<ListView
android:id="@+id/lv"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#000000"
android:focusableInTouchMode="false"
android:listSelector="@android:color/transparent"
android:layout_weight="2.0"
android:divider="#000000"
android:headerDividersEnabled="false"
android:footerDividersEnabled="false"
android:dividerHeight="8dp"
android:drawSelectorOnTop="false"
/>
</RelativeLayout>
LazyAdapter.java
LazyAdapter.java
public class LazyAdapter extends BaseAdapter {
private Activity activity;
private String data[];
private LayoutInflater inflater=null;
public ImageLoader imageLoader;
DisplayImageOptions options;
public LazyAdapter(Activity a, String[] d) {
activity = a;
data=d;
inflater = (LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
File cacheDir = StorageUtils.getOwnCacheDirectory(a, "MyFolderCache");
// Get singletone instance of ImageLoader
imageLoader = ImageLoader.getInstance();
// Create configuration for ImageLoader (all options are optional)
ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(a)
// You can pass your own memory cache implementation
.discCacheExtraOptions(1024, 1024, CompressFormat.PNG, 100)
.discCache(new UnlimitedDiscCache(cacheDir)) // You can pass your own disc cache implementation
.discCacheFileNameGenerator(new HashCodeFileNameGenerator())
.enableLogging()
.build();
// Initialize ImageLoader with created configuration. Do it once.
imageLoader.init(config);
//imageLoader.init(ImageLoaderConfiguration.createDefault(a));
// imageLoader=new ImageLoader(activity.getApplicationContext());
options = new DisplayImageOptions.Builder()
.showStubImage(R.drawable.ic_launcher)
.cacheInMemory()
.cacheOnDisc()
.displayer(new RoundedBitmapDisplayer(20))
.build();
}
public int getCount() {
return data.length;
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
View vi=convertView;
ViewHolder vh = new ViewHolder();;
if(convertView==null)
{
vi = inflater.inflate(R.layout.row, null);
vh.iv=(ImageView)vi.findViewById(R.id.ivv);
vh.pb= (ProgressBar)vi.findViewById(R.id.pb);
vh.tv = (TextView) vi.findViewById(R.id.textView1);
vh.tv1= (TextView) vi.findViewById(R.id.textView2);
}
vh.tv.setText("Image in postion =");
vh.tv1.setText(""+position);
display(vh.iv, data[position], vh.pb);
//imageLoader.displayImage(data.get(position).toString(), image,options);
return vi;
}
public void display(ImageView img, String url, final ProgressBar spinner)
{
imageLoader.displayImage(url, img, options, new ImageLoadingListener() {
@Override
public void onLoadingStarted(String imageUri, View view) {
spinner.setVisibility(View.VISIBLE);
}
@Override
public void onLoadingFailed(String imageUri, View view, FailReason failReason) {
spinner.setVisibility(View.GONE);
}
@Override
public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {
spinner.setVisibility(View.GONE);
}
@Override
public void onLoadingCancelled(String imageUri, View view) {
}
});
}
public static class ViewHolder
{
ImageView iv;
TextView tv,tv1;
ProgressBar pb;
}
}
row.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:src="@drawable/ic_launcher" />
<ProgressBar
android:id="@+id/pb"
android:layout_centerInParent="true"
android:layout_gravity="center"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/textView2"
android:layout_alignParentLeft="true"
android:layout_marginBottom="21dp"
android:layout_marginLeft="31dp"
android:text="TextView" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView1"
android:layout_alignParentBottom="true"
android:text="TextView" />
</RelativeLayout>
添加许可清单
Add permission in manifest
<uses-permission android:name="android.permission.INTERNET"/>
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