下载图像并将其加载到listitem中的imageview中

Question

我是新来的android，我在一个应用程序上工作。我想下载一个图像并将其显示在列表项中。我为此使用了许多功能。我的代码无误地运行，但图像不显示在我的代码的一部分屏幕上。

public loader(Context context, String[] img) { 
     super(context, R.layout.item, img); 

     this.context = context; 
     this.img = img; 

     inflater = LayoutInflater.from(context); 

    } 

    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 
     // ImageView imgshow = (ImageView) findViewById(R.id.image1); 

     if (null == convertView) { 
      convertView = inflater.inflate(R.layout.item, parent, false); 

     } 
     ImageView imageView = (ImageView) convertView.findViewById(R.id.imageview); 
     //first method 
     // Glide.with(context) 
     // .load(img[position]) 
     //.into(imageView); 
     //second method 
     DownloadImageTask download=new DownloadImageTask((ImageView) convertView.findViewById(R.id.imageview)); 
     download.execute("http://previews.123rf.com/images/faysalfarhan/faysalfarhan1402/faysalfarhan140200008/25989999-Back-left-arrow-icon-glossy-purple-button-Stock-Photo.jpg"); 
     //new DownloadImageTask((ImageView) convertView.findViewById(R.id.imageview)) 
     //.execute(img[position]); 
     //third method 
     //Picasso.with(context).load(img[position]).into(imageView); 
     //Log.e("image_url","https://upload.wikimedia.org/wikipedia/commons/thumb/2/27/Square_200x200.svg/1024px-Square_200x200.svg.png"); 
     return convertView; 





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


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

     protected Bitmap doInBackground(String... urls) { 
      String urldisplay = "http://previews.123rf.com/images/faysalfarhan/faysalfarhan1402/faysalfarhan140200008/25989999-Back-left-arrow-icon-glossy-purple-button-Stock-Photo.jpg"; 

      Bitmap mIcon11 = null; 
      // Toast.makeText(mainpage.this ,urldisplay ,Toast.LENGTH_SHORT).show(); 

      TextView t=(TextView)findViewById(R.id.texttt); 
      // t.setText(urldisplay); 

      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); 


     } 
    } 


} 

我把用在我的名单（IMG是一个字符串我保存网址，并显示它们的阵列，但对于测试我的装载机类中一个图像的URL替换）

String[] img = new String[1000]; 
    loader im=new loader(mainpage.this,img); 

    lv.setAdapter(im); 

Answer 1

你无法直接在ImageView中设置图像。你必须到图像转换成位图，然后设置

public static Bitmap getBitmapFromURL(String src) { 
    try { 
     Log.e("src",src); 
     URL url = new URL(src); 
     HttpURLConnection connection = (HttpURLConnection) url.openConnection(); 
     connection.setDoInput(true); 
     connection.connect(); 
     InputStream input = connection.getInputStream(); 
     Bitmap myBitmap = BitmapFactory.decodeStream(input); 
     Log.e("Bitmap","returned"); 
     return myBitmap; 
    } catch (IOException e) { 
     e.printStackTrace(); 
     Log.e("Exception",e.getMessage()); 
     return null; 
    } 
} 

然后设置ImageView的：

imageView.setImageBitmap(getBitmapFromURL(url)); 

试试这个，希望它可以帮助你

Answer 2

使用piccasso。

要使用piccasso增加其添加

compile 'com.squareup.picasso:picasso:2.5.2' 

到您的应用水平gradle这个。而 使用这种

Picasso.with(context).load("http://previews.123rf.com/images/faysalfarhan/faysalfarhan1402/faysalfarhan140200008/25989999-Back-left-arrow-icon-glossy-purple-button-Stock-Photo.jpg").into(imageview); 

或者你getCount将（）方法返回0。 （或添加它）将其更改为

@Override 
    public int getCount() { 
     return img.length; 
    } 

Answer 3

Picasso.with(context).load("http://i.imgur.com/DvpvklR.png").into(imageView); 

Answer 4

使用滑翔

依赖滑翔：编译 'com.github.bumptech.glide：滑翔：3.7.0'

，并添加代码

ImageView imageView = (ImageView) findViewById(R.id.my_image_view); 

    Glide.with(this).load("https://s3-us-west-1.amazonaws.com/powr/defaults/image-slider2.jpg").into(imageView);