Question

如果操作系统版本为4.3，“BitmapFactory.decodeStream（inputStream）”在AsyncTask中返回null有一点问题，但如果操作系统版本是2.3.3则运行良好，这里有一个示例：

public class GetImagesTask extends AsyncTask<Void, Void, InputStream> {

private URL url;
private BitmapFactory.Options opts;
private ImageView imageView;

public GetImagesTask(URL url, BitmapFactory.Options opts,
        ImageView imageView) {
    this.url = url;
    this.opts = opts;
    this.imageView = imageView;
}

@Override
protected InputStream doInBackground(Void... arg0) {
    // TODO Auto-generated method stub
    InputStream inputStream = null;
    try {
        inputStream = url.openConnection().getInputStream();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        return null;
    }

    return inputStream;
}

@Override
protected void onPostExecute(InputStream inputStream) {
    // TODO Auto-generated method stub
    super.onPostExecute(inputStream);

    Bitmap bitmap = null;
    try {
        bitmap = BitmapFactory.decodeStream(inputStream);
        System.out.println();
    } catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    if (bitmap != null) {
        imageView.setImageBitmap(bitmap);
    } else {
        imageView.setImageResource(R.drawable.loader);
    }

}

}

这里我称之为asynctask，：

 @Override
public View getView(int position, View convertView, ViewGroup parent) {

    Model.LoadModel(items);

    LayoutInflater inflater = (LayoutInflater) context
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

    View rowView = inflater.inflate(rowResourceId, parent, false);
    ImageView imageView = (ImageView) rowView.findViewById(R.id.imageView);
    TextView textView = (TextView) rowView.findViewById(R.id.textView);

    int id = items.get(position).getId();
    String imageFile = Model.GetbyId(id).iconFile;

    textView.setText(Model.GetbyId(id).name);

    // Loader image - will be shown before loading image
    int loader = R.drawable.loader;

    // Image url
    String image_url = "IP and PORT" + imageFile;

    URL url = null;
    Bitmap bmp = null;

    try {
        url = new URL(image_url);
    } catch (MalformedURLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    BitmapFactory.Options opts = new BitmapFactory.Options();
    opts.inDither = false; // Disable Dithering mode
    opts.inPurgeable = true; // Tell to gc that whether it needs free
                                // memory, the Bitmap can be cleared
    opts.inInputShareable = true; // Which kind of reference will be
                                    // used to recover the Bitmap data
                                    // after being clear, when it will
                                    // be used in the future
    opts.inTempStorage = new byte[32 * 1024];
    opts.inSampleSize = 8;
    getImagesTask = new GetImagesTask(url, opts, imageView);
    getImagesTask.execute((Void) null);

    return rowView;

}

任何人都可以帮忙吗？

这是logcat：

09-05 08:15:59.975: W/System.err(1060):     at java.net.PlainSocketImpl$PlainSocketInputStream.read(PlainSocketImpl.java:240)
09-05 08:15:59.975: W/System.err(1060):     at java.io.BufferedInputStream.read(BufferedInputStream.java:304)
09-05 08:15:59.975: W/System.err(1060):     at libcore.net.http.FixedLengthInputStream.read(FixedLengthInputStream.java:45)
09-05 08:15:59.975: W/System.err(1060):     at java.io.BufferedInputStream.fillbuf(BufferedInputStream.java:168)
09-05 08:15:59.975: W/System.err(1060):     at java.io.BufferedInputStream.read(BufferedInputStream.java:309)
09-05 08:15:59.975: W/System.err(1060):     at android.graphics.BitmapFactory.nativeDecodeStream(Native Method)
09-05 08:15:59.975: W/System.err(1060):     at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:530)
09-05 08:15:59.975: W/System.err(1060):     at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:603)
09-05 08:15:59.975: W/System.err(1060):     at com.domainintegrators.fitnessyard.tasks.GetImagesTask.onPostExecute(GetImagesTask.java:49)
09-05 08:15:59.975: W/System.err(1060):     at com.domainintegrators.fitnessyard.tasks.GetImagesTask.onPostExecute(GetImagesTask.java:1)
09-05 08:15:59.975: W/System.err(1060):     at android.os.AsyncTask.finish(AsyncTask.java:631)
09-05 08:15:59.975: W/System.err(1060):     at android.os.AsyncTask.access$600(AsyncTask.java:177)
09-05 08:15:59.975: W/System.err(1060):     at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:644)
09-05 08:15:59.975: W/System.err(1060):     at android.os.Handler.dispatchMessage(Handler.java:99)
09-05 08:15:59.975: W/System.err(1060):     at android.os.Looper.loop(Looper.java:137)
09-05 08:15:59.975: W/System.err(1060):     at android.app.ActivityThread.main(ActivityThread.java:5103)
09-05 08:15:59.975: W/System.err(1060):     at java.lang.reflect.Method.invokeNative(Native Method)
09-05 08:15:59.975: W/System.err(1060):     at java.lang.reflect.Method.invoke(Method.java:525)
09-05 08:15:59.975: W/System.err(1060):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
09-05 08:15:59.975: W/System.err(1060):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
09-05 08:15:59.975: W/System.err(1060):     at dalvik.system.NativeStart.main(Native Method)
09-05 08:15:59.975: D/skia(1060): ---- read threw an exception
09-05 08:15:59.975: D/skia(1060): --- SkImageDecoder::Factory returned null

Answer 1

您无法在UI线程中使用互联网连接。重新定位

 Bitmap bitmap = null;
try {
    bitmap = BitmapFactory.decodeStream(inputStream);
    System.out.println();
} catch (Exception e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}

到doInBackground程序部分和

if (bitmap != null) {
    imageView.setImageBitmap(bitmap);
}

留在onPostExecute。 Actualy你不能在＆＃34; doInBackground＆＃34;只得到连接。您在后台和UI线程中的所有工作仅用于操纵UI元素。

Android：BitmapFactory.decodeStream（inputStream）返回null

1 个答案: