Question

我写了一个代码来从互联网上下载图像。我必须在动态创建的ImageView中显示它。

我收到的错误是只有创建视图层次结构的原始线程才能触及其视图。我知道我必须写一个句柄，但我该怎么做？

这是我的代码：

public class ResimCek implements Runnable {

        int resimID = 0;

        public ResimCek(int parcaID) {
            // store parameter for later user
            resimID = parcaID;
        }

        public void run() {

            int resID = getResources().getIdentifier(Integer.toString(resimID) , "tag", getPackageName()); 
            ImageView resim = (ImageView) findViewById(resID);

            Drawable image = ImageOperations(getBaseContext(),"http://141.11.11.206/parca/" + Integer.toString(resimID) + ".jpg" ,"I" + Integer.toString(resimID) + ".jpg");

            // I AM GETTING ERROR HERE ******************
            resim.setImageDrawable(image); // *************************
        }
    }

    private Drawable ImageOperations(Context ctx, String url, String saveFilename) {
        try {
            InputStream is = (InputStream) this.fetch(url);
            Drawable d = Drawable.createFromStream(new URL(url).openConnection().getInputStream(),saveFilename);
            return d;
        } catch (MalformedURLException e) {
            e.printStackTrace();
            return null;
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }
    }

    public Object fetch(String address) throws MalformedURLException,IOException {
        URL url = new URL(address);
        Object content = url.getContent();
        return content;
    }
    private void MalzemeEkle(String malzemeKodu, String malzemeTanimi) {
        ImageView parcaresmi = new ImageView(this);
        parcaresmi.setId(Integer.parseInt(malzemeKodu));
        Runnable r = new ResimCek(Integer.parseInt(malzemeKodu)); 
        new Thread(r).start(); 
}

Answer 1

public class ResimCek implements Runnable {

        int resimID = 0;

        public ResimCek(int parcaID) {
            // store parameter for later user
            resimID = parcaID;
        }

        public void run() {

            int resID = getResources().getIdentifier(Integer.toString(resimID) , "tag", getPackageName()); 
            ImageView resim = (ImageView) findViewById(resID);

            Drawable image = ImageOperations(getBaseContext(),"http://141.11.11.206/parca/" + Integer.toString(resimID) + ".jpg" ,"I" + Integer.toString(resimID) + ".jpg");

            // I AM GETTING ERROR HERE ******************
            resim.setImageDrawable(image); // *************************
        }
    }



new Handler().post(new ResimCek(Integer.parseInt(malzemeKodu))); instead of new Thread(r).start();

无论如何，如果这是一个活动..那么

runOnUIThread(new ResimCek(Integer.parseInt(malzemeKodu))); `instead of new Thread(r).start();`

也会有效..

Answer 2

您应该创建一个处理程序：

    final Handler   myHandler   = new Handler() {
                                    @Override
                                    public void handleMessage(Message msg)
                                    {
                                        /*do all your ui action here to display the image ()*/
                                        resim.setImageDrawable(image);
                                    }
                                };

在下载图像时你的runnable中调用：

myHandler.sendEmptyMessage(0);

您可以在此处找到处理程序的其他选项 http://developer.android.com/reference/android/os/Handler.html

从其他线程更改视图

2 个答案: