创建应用后更新 UI答案

【问题标题】：Update UI after app is created创建应用后更新 UI
【发布时间】：2014-06-06 07:23:47
【问题描述】：

我正在开发一个在其主要布局中具有滚动视图和图像按钮的 Android 应用。我使用 drawable 文件夹中的图像并通过它们的 id 调用它们。

//AboutScreen.java class
    private ImageButton mStartButton3;

    mStartButton3 = (ImageButton) findViewById(R.id.woops3); 

    mStartButton3.setOnClickListener(this);


//MainLayout.xml
    <ImageButton
        android:id="@+id/woops3"
        android:background="@android:color/transparent"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:fontFamily="sans-serif"
        android:gravity="center_horizontal|center_vertical"
        android:src="@drawable/woops6"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
             android:layout_marginTop="10dp"
        android:text="@string/button_start"
        android:textSize="@dimen/menu_title" />

但我想通过在启动画面期间从 json Web 服务下载的图像来更新这些图像（图像按钮）。

可以吗？

谢谢。

【问题讨论】：

标签： android xml user-interface updates imagebutton

【解决方案1】：

去这个：

    public void onCreate(Bundle savedInstanceState) 

{ 

Bitmap bitmap = DownloadImage("Your URL");

ImageView img = (ImageView) findViewById(R.id.imagefromserver);

img.setImageBitmap(bitmap);

}


private InputStream OpenHttpConnection(String urlString) 
    throws IOException

 {

 InputStream in = null;

        int response = -1;

        URL url = new URL(urlString); 
        URLConnection conn = url.openConnection();

        if (!(conn instanceof HttpURLConnection))                     
            throw new IOException("Not an HTTP connection");

        try{
            HttpURLConnection httpConn = (HttpURLConnection) conn;
            httpConn.setAllowUserInteraction(false);
            httpConn.setInstanceFollowRedirects(true);
            httpConn.setRequestMethod("GET");
            httpConn.connect(); 

            response = httpConn.getResponseCode();                 
            if (response == HttpURLConnection.HTTP_OK) {
                in = httpConn.getInputStream();                                 
            }                     
        }
        catch (Exception ex)
        {
            throw new IOException("Error connecting");            
        }
        return in;     
    }
    private Bitmap DownloadImage(String URL)
    {        
        Bitmap bitmap = null;
        InputStream in = null;        
        try {
            in = OpenHttpConnection(URL);
            bitmap = BitmapFactory.decodeStream(in);
            in.close();
        } catch (IOException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }
        return bitmap;                
    }

【讨论】：