Question

我正在尝试通过从服务器获取到ImageView的URL来设置圆形位图，但有时会强制停止，因此这是我的异步圆形图像加载类：

public class AsyncTaskLoadImage  extends AsyncTask<String, String, Bitmap> {
private final static String TAG = "AsyncTaskLoadImage";
private ImageView imageView;
public AsyncTaskLoadImage(ImageView imageView) {
  this.imageView = imageView;
}

@Override
protected Bitmap doInBackground(String... params) {
  Bitmap bitmap = null;
  try {
    URL url = new URL(params[0]);
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inSampleSize = 8;
    bitmap = BitmapFactory.decodeStream((InputStream)url.getContent(), null, options);

  } catch (Exception e) {
    Log.e(TAG, e.getMessage());
  }
  return bitmap;
}

@Override
protected void onPostExecute(Bitmap bitmap) {
  Bitmap circleBitmap = null;
  circleBitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Bitmap.Config.ARGB_4444);
  BitmapShader shader = new BitmapShader (bitmap,  Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
  Paint paint = new Paint();
  paint.setShader(shader);
  paint.setAntiAlias(true);
  Canvas c = new Canvas(circleBitmap);
  c.drawCircle(bitmap.getWidth()/2, bitmap.getHeight()/2, bitmap.getWidth()/2, paint);
  imageView.setImageBitmap(circleBitmap);
}
}

这是我的日志猫：

10-27 13:43:07.482 19717-19717/com.morlunk.mumbleclient.free E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.morlunk.mumbleclient.free, PID: 19717
java.lang.NullPointerException
    at com.morlunk.mumbleclient.app.SearchListAdapter$AsyncTaskLoadImage.onPostExecute(SearchListAdapter.java:140)
    at com.morlunk.mumbleclient.app.SearchListAdapter$AsyncTaskLoadImage.onPostExecute(SearchListAdapter.java:115)
    at android.os.AsyncTask.finish(AsyncTask.java:632)
    at android.os.AsyncTask.access$600(AsyncTask.java:177)
    at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:645)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:136)
    at android.app.ActivityThread.main(ActivityThread.java:5105)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:515)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:792)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:608)
    at dalvik.system.NativeStart.main(Native Method)

其中发生错误的行是：

circleBitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Bitmap.Config.ARGB_4444);
BitmapShader shader = new BitmapShader (bitmap,  Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);

太奇怪了，因为有时错误发生在第一行，有时发生在第二行，有时没有强制停止。有人知道我该怎么解决吗？

Answer 1

我认为使用“库”在Imageview中设置服务器图像的最佳方法，

类似于以下代码：

Picasso
  .with(context)
  .load(url)
  .placeholder(placeHolderDrawable)
  .error(errorDrawable)
  .transform(circleTransform)
  .into(imageView);

，以及从此链接复制的circleTransform的代码：https://gist.github.com/julianshen/5829333

public class CircleTransform implements Transformation {
    @Override
    public Bitmap transform(Bitmap source) {
        int size = Math.min(source.getWidth(), source.getHeight());

        int x = (source.getWidth() - size) / 2;
        int y = (source.getHeight() - size) / 2;

        Bitmap squaredBitmap = Bitmap.createBitmap(source, x, y, size, size);
        if (squaredBitmap != source) {
            source.recycle();
        }

        Bitmap bitmap = Bitmap.createBitmap(size, size, source.getConfig());

        Canvas canvas = new Canvas(bitmap);
        Paint paint = new Paint();
        BitmapShader shader = new BitmapShader(squaredBitmap, BitmapShader.TileMode.CLAMP, BitmapShader.TileMode.CLAMP);
        paint.setShader(shader);
        paint.setAntiAlias(true);

        float r = size/2f;
        canvas.drawCircle(r, r, r, paint);

        squaredBitmap.recycle();
        return bitmap;
    }

    @Override
    public String key() {
        return "circle";
    }
}

强制停止创建圆形位图

1 个答案: