如何在Android中通过URL加载ImageView？ [关闭]-Java 学习之路

483

如何在_849658中使用URL引用的图像？

23 回答

imageView.setImageBitmap(BitmapFactory.decodeStream(imageUrl.openStream()));//try/catch IOException and MalformedURLException outside

回复于 2024-05-10T12:50:41+08:00

来自Android developer：

// show The Image in a ImageView
new DownloadImageTask((ImageView) findViewById(R.id.imageView1))
            .execute("http://java.sogeti.nl/JavaBlog/wp-content/uploads/2009/04/android_icon_256.png");

public void onClick(View v) {
    startActivity(new Intent(this, IndexActivity.class));
    finish();

}

private class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {
    ImageView bmImage;

    public DownloadImageTask(ImageView bmImage) {
        this.bmImage = bmImage;
    }

    protected Bitmap doInBackground(String... urls) {
        String urldisplay = urls[0];
        Bitmap mIcon11 = null;
        try {
            InputStream in = new java.net.URL(urldisplay).openStream();
            mIcon11 = BitmapFactory.decodeStream(in);
        } catch (Exception e) {
            Log.e("Error", e.getMessage());
            e.printStackTrace();
        }
        return mIcon11;
    }

    protected void onPostExecute(Bitmap result) {
        bmImage.setImageBitmap(result);
    }
}

确保您在 AndroidManifest.xml 中设置了以下权限才能访问互联网 .

<uses-permission android:name="android.permission.INTERNET" />

回复于 2024-05-10T12:50:41+08:00

你必须先下载图像

public static Bitmap loadBitmap(String url) {
    Bitmap bitmap = null;
    InputStream in = null;
    BufferedOutputStream out = null;

    try {
        in = new BufferedInputStream(new URL(url).openStream(), IO_BUFFER_SIZE);

        final ByteArrayOutputStream dataStream = new ByteArrayOutputStream();
        out = new BufferedOutputStream(dataStream, IO_BUFFER_SIZE);
        copy(in, out);
        out.flush();

        final byte[] data = dataStream.toByteArray();
        BitmapFactory.Options options = new BitmapFactory.Options();
        //options.inSampleSize = 1;

        bitmap = BitmapFactory.decodeByteArray(data, 0, data.length,options);
    } catch (IOException e) {
        Log.e(TAG, "Could not load Bitmap from: " + url);
    } finally {
        closeStream(in);
        closeStream(out);
    }

    return bitmap;
}

然后使用Imageview.setImageBitmap将位图设置为ImageView

回复于 2024-05-10T12:50:41+08:00

70
1. Picasso允许在您的应用程序中轻松加载图像 - 通常在一行代码中！

Use Gradle:
```
implementation 'com.squareup.picasso:picasso:2.71828'
```
只需一行代码！
```
Picasso.get().load("http://i.imgur.com/DvpvklR.png").into(imageView);
```
2. Glide适用于Android的图像加载和缓存库专注于平滑滚动

Use Gradle:
```
repositories {
  mavenCentral() 
  google()
}

dependencies {
   implementation 'com.github.bumptech.glide:glide:4.7.1'
   annotationProcessor 'com.github.bumptech.glide:compiler:4.7.1'
}
```
// For a simple view:
```
Glide.with(this).load("http://i.imgur.com/DvpvklR.png").into(imageView);
```
3. fresco是一个功能强大的系统，用于在Android应用程序中显示图像.Fresco负责图像加载和显示，因此您不必这样做 .

Getting Started with Fresco
回复于 2024-05-10T12:50:41+08:00
3

我写了一个类来处理这个问题，因为它似乎是我各种项目中反复出现的需求：

https://github.com/koush/UrlImageViewHelper

UrlImageViewHelper将使用在URL处找到的图像填充ImageView . 该示例将执行Google图像搜索并异步加载/显示结果 . UrlImageViewHelper将自动下载，保存和缓存BitmapDrawables的所有图像URL . 重复的网址不会被加载到内存中两次 . 位图内存通过使用弱引用哈希表进行管理，因此只要您不再使用该图像，就会自动对其进行垃圾回收 .

回复于 2024-05-10T12:50:41+08:00

无论如何，人们会将我的评论发布为答案 . 我发布了 .

URL newurl = new URL(photo_url_str); 
mIcon_val = BitmapFactory.decodeStream(newurl.openConnection() .getInputStream());
profile_photo.setImageBitmap(mIcon_val);

谢谢 .

回复于 2024-05-10T12:50:41+08:00

如果您基于按钮单击加载图像，则上面接受的答案很棒，但是如果您在新活动中执行此操作，则会将UI冻结一两秒 . 环顾四周，我发现一个简单的asynctask消除了这个问题 .

要使用asynctask，请在活动结束时添加此类：

private class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {
    ImageView bmImage;

    public DownloadImageTask(ImageView bmImage) {
        this.bmImage = bmImage;
    }

    protected Bitmap doInBackground(String... urls) {
        String urldisplay = urls[0];
        Bitmap mIcon11 = null;
        try {
            InputStream in = new java.net.URL(urldisplay).openStream();
            mIcon11 = BitmapFactory.decodeStream(in);
        } catch (Exception e) {
            Log.e("Error", e.getMessage());
            e.printStackTrace();
        }
        return mIcon11;
    }

    protected void onPostExecute(Bitmap result) {
        bmImage.setImageBitmap(result);
    }    
}

并使用以下命令从onCreate（）方法调用：

new DownloadImageTask((ImageView) findViewById(R.id.imageView1))
        .execute(MY_URL_STRING);

结果是一个快速加载的活动和一个图像视图，它会在一瞬间显示，具体取决于用户的网络速度 .

回复于 2024-05-10T12:50:41+08:00

您还可以使用此LoadingImageView视图从URL加载图像：

http://blog.blundellapps.com/imageview-with-loading-spinner/

从该链接添加类文件后，您可以实例化URL图像视图：

在xml中：

<com.blundell.tut.LoaderImageView
  android:id="@+id/loaderImageView"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  image="http://developer.android.com/images/dialog_buttons.png"
 />

在代码中：

final LoaderImageView image = new LoaderImageView(this, "http://developer.android.com/images/dialog_buttons.png");

并使用以下方法更新它

image.setImageDrawable("http://java.sogeti.nl/JavaBlog/wp-content/uploads/2009/04/android_icon_256.png");

回复于 2024-05-10T12:50:41+08:00

public class LoadWebImg extends Activity {

String image_URL=
 "http://java.sogeti.nl/JavaBlog/wp-content/uploads/2009/04/android_icon_256.png";

   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.main);

       ImageView bmImage = (ImageView)findViewById(R.id.image);
    BitmapFactory.Options bmOptions;
    bmOptions = new BitmapFactory.Options();
    bmOptions.inSampleSize = 1;
    Bitmap bm = LoadImage(image_URL, bmOptions);
    bmImage.setImageBitmap(bm);
   }

   private Bitmap LoadImage(String URL, BitmapFactory.Options options)
   {       
    Bitmap bitmap = null;
    InputStream in = null;       
       try {
           in = OpenHttpConnection(URL);
           bitmap = BitmapFactory.decodeStream(in, null, options);
           in.close();
       } catch (IOException e1) {
       }
       return bitmap;               
   }

private InputStream OpenHttpConnection(String strURL) throws IOException{
 InputStream inputStream = null;
 URL url = new URL(strURL);
 URLConnection conn = url.openConnection();

 try{
  HttpURLConnection httpConn = (HttpURLConnection)conn;
  httpConn.setRequestMethod("GET");
  httpConn.connect();

  if (httpConn.getResponseCode() == HttpURLConnection.HTTP_OK) {
   inputStream = httpConn.getInputStream();
  }
 }
 catch (Exception ex)
 {
 }
 return inputStream;
}
}

回复于 2024-05-10T12:50:41+08:00

嗨，我有最简单的代码试试这个

public class ImageFromUrlExample extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);  
            ImageView imgView =(ImageView)findViewById(R.id.ImageView01);
            Drawable drawable = LoadImageFromWebOperations("http://www.androidpeople.com/wp-content/uploads/2010/03/android.png");
            imgView.setImageDrawable(drawable);

    }

    private Drawable LoadImageFromWebOperations(String url)
    {
          try{
        InputStream is = (InputStream) new URL(url).getContent();
        Drawable d = Drawable.createFromStream(is, "src name");
        return d;
      }catch (Exception e) {
        System.out.println("Exc="+e);
        return null;
      }
    }
   }

main.xml中

<LinearLayout 
    android:id="@+id/LinearLayout01"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    xmlns:android="http://schemas.android.com/apk/res/android">
   <ImageView 
       android:id="@+id/ImageView01"
       android:layout_height="wrap_content" 
       android:layout_width="wrap_content"/>

试试这个

回复于 2024-05-10T12:50:41+08:00

5
我最近发现了一个线程here，因为我必须对带有图像的列表视图做类似的事情，但原理很简单，因为你可以在那里显示的第一个示例类中读取（通过jleedev） . 你得到图像的输入流（来自网络）
```
private InputStream fetch(String urlString) throws MalformedURLException, IOException {
    DefaultHttpClient httpClient = new DefaultHttpClient();
    HttpGet request = new HttpGet(urlString);
    HttpResponse response = httpClient.execute(request);
    return response.getEntity().getContent();
}
```
然后将图像存储为Drawable，然后将其传递给ImageView（通过setImageDrawable） . 再从上面的代码片段看一下整个线程 .
```
InputStream is = fetch(urlString);
Drawable drawable = Drawable.createFromStream(is, "src");
```
回复于 2024-05-10T12:50:41+08:00
59

这里有很多好消息...我最近发现了一个名为SmartImageView的类，到目前为止看起来效果非常好 . 非常容易合并和使用 .

http://loopj.com/android-smart-image-view/

https://github.com/loopj/android-smart-image-view

UPDATE ：我最后写了一个blog post about this，所以请查看它以获得有关使用SmartImageView的帮助 .

2ND UPDATE ：我现在总是使用Picasso（见上文）并强烈推荐它 . :)

回复于 2024-05-10T12:50:41+08:00
7
对我来说这个任务最好的现代图书馆是Square的Picasso . 它允许通过URL使用单行将图像加载到ImageView：
```
Picasso.with(context).load("http://i.imgur.com/DvpvklR.png").into(imageView);
```
回复于 2024-05-10T12:50:41+08:00

这是一个迟到的回复，正如上面提到的 AsyncTask 将会和谷歌搜索后我找到了另一种方法来解决这个问题 .

Drawable drawable = Drawable.createFromStream((InputStream) new URL("url").getContent(), "src");

imageView.setImageDrawable(drawable);

这是完整的功能：

public void loadMapPreview () {
    //start a background thread for networking
    new Thread(new Runnable() {
        public void run(){
            try {
                //download the drawable
                final Drawable drawable = Drawable.createFromStream((InputStream) new URL("url").getContent(), "src");
                //edit the view in the UI thread
                imageView.post(new Runnable() {
                    public void run() {
                        imageView.setImageDrawable(drawable);
                    }
                });
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }).start();
}

不要忘记在 AndroidManifest.xml 中添加以下权限以访问互联网 .

<uses-permission android:name="android.permission.INTERNET" />

我自己尝试了这个，但我还没有遇到任何问题 .

回复于 2024-05-10T12:50:41+08:00

129

这会对你有所帮助......

定义imageview并将图像加载到其中.....

Imageview i = (ImageView) vv.findViewById(R.id.img_country);
i.setImageBitmap(DownloadFullFromUrl(url));

然后定义此方法：

public Bitmap DownloadFullFromUrl(String imageFullURL) {
    Bitmap bm = null;
    try {
        URL url = new URL(imageFullURL);
        URLConnection ucon = url.openConnection();
        InputStream is = ucon.getInputStream();
        BufferedInputStream bis = new BufferedInputStream(is);
        ByteArrayBuffer baf = new ByteArrayBuffer(50);
        int current = 0;
        while ((current = bis.read()) != -1) {
            baf.append((byte) current);
        }
        bm = BitmapFactory.decodeByteArray(baf.toByteArray(), 0,
                baf.toByteArray().length);
    } catch (IOException e) {
        Log.d("ImageManager", "Error: " + e);
    }
    return bm;
}

回复于 2024-05-10T12:50:41+08:00

private Bitmap getImageBitmap(String url) {
        Bitmap bm = null;
        try {
            URL aURL = new URL(url);
            URLConnection conn = aURL.openConnection();
            conn.connect();
            InputStream is = conn.getInputStream();
            BufferedInputStream bis = new BufferedInputStream(is);
            bm = BitmapFactory.decodeStream(bis);
            bis.close();
            is.close();
       } catch (IOException e) {
           Log.e(TAG, "Error getting bitmap", e);
       }
       return bm;
    }

回复于 2024-05-10T12:50:41+08:00

6

一个简单而干净的方法是使用开源库Prime .

回复于 2024-05-10T12:50:41+08:00

String img_url= //url of the image
    URL url=new URL(img_url);
    Bitmap bmp; 
    bmp=BitmapFactory.decodeStream(url.openConnection().getInputStream());
    ImageView iv=(ImageView)findviewById(R.id.imageview);
    iv.setImageBitmap(bmp);

回复于 2024-05-10T12:50:41+08:00

这段代码经过测试，完全正常 .

URL req = new URL(
"http://java.sogeti.nl/JavaBlog/wp-content/uploads/2009/04/android_icon_256.png"
);
Bitmap mIcon_val = BitmapFactory.decodeStream(req.openConnection()
                  .getInputStream());

回复于 2024-05-10T12:50:41+08:00

150

Working for imageView in any container , like listview grid view , normal layout

private class LoadImagefromUrl extends AsyncTask< Object, Void, Bitmap > {
        ImageView ivPreview = null;

        @Override
        protected Bitmap doInBackground( Object... params ) {
            this.ivPreview = (ImageView) params[0];
            String url = (String) params[1];
            System.out.println(url);
            return loadBitmap( url );
        }

        @Override
        protected void onPostExecute( Bitmap result ) {
            super.onPostExecute( result );
            ivPreview.setImageBitmap( result );
        }
    }

    public Bitmap loadBitmap( String url ) {
        URL newurl = null;
        Bitmap bitmap = null;
        try {
            newurl = new URL( url );
            bitmap = BitmapFactory.decodeStream( newurl.openConnection( ).getInputStream( ) );
        } catch ( MalformedURLException e ) {
            e.printStackTrace( );
        } catch ( IOException e ) {

            e.printStackTrace( );
        }
        return bitmap;
    }
/** Usage **/
  new LoadImagefromUrl( ).execute( imageView, url );

回复于 2024-05-10T12:50:41+08:00

具有异常处理和异步任务的版本：

AsyncTask<URL, Void, Boolean> asyncTask = new AsyncTask<URL, Void, Boolean>() {
    public Bitmap mIcon_val;
    public IOException error;

    @Override
    protected Boolean doInBackground(URL... params) {
        try {
            mIcon_val = BitmapFactory.decodeStream(params[0].openConnection().getInputStream());
        } catch (IOException e) {
            this.error = e;
            return false;
        }
        return true;
    }

    @Override
    protected void onPostExecute(Boolean success) {
        super.onPostExecute(success);
        if (success) {
            image.setImageBitmap(mIcon_val);
        } else {
            image.setImageBitmap(defaultImage);
        }
    }
};
try {
    URL url = new URL(url);
    asyncTask.execute(url);
} catch (MalformedURLException e) {
    e.printStackTrace();
}

回复于 2024-05-10T12:50:41+08:00

676

Try this way,hope this will help you to solve your problem.

在这里，我解释了如何使用“AndroidQuery”外部库以asyncTask方式从url / server加载图像，同时还将缓存加载的图像添加到设备文件或缓存区域 .

下载"AndroidQuery" library from here
将此jar复制/粘贴到项目lib文件夹，并将此库添加到项目构建路径
现在我展示了如何使用它的演示 .

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center">

        <FrameLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content">

            <ImageView
                android:id="@+id/imageFromUrl"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:adjustViewBounds="true"/>
            <ProgressBar
                android:id="@+id/pbrLoadImage"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="center"/>

        </FrameLayout>
    </LinearLayout>

MainActivity.java

public class MainActivity extends Activity {

private AQuery aQuery;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    aQuery = new AQuery(this);
    aQuery.id(R.id.imageFromUrl).progress(R.id.pbrLoadImage).image("http://itechthereforeiam.com/wp-content/uploads/2013/11/android-gone-packing.jpg",true,true);
 }
}

Note : Here I just implemented common method to load image from url/server but you can use various types of method which can be provided by "AndroidQuery"to load your image easily.

回复于 2024-05-10T12:50:41+08:00

3

Android Query可以为您处理更多内容（如缓存和加载进度） .

看看here .

我认为这是最好的方法 .

回复于 2024-05-10T12:50:41+08:00

如何在Android中通过URL加载ImageView？ [关闭]

23 回答

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