我在这里关注 developer.android 网站,我正在尝试从 url 加载大图像(即 1024 x 900)我的代码在我的 Google Nexus 中运行良好,但在 Nexus 上不起作用。
这是我的代码
public static Bitmap getBitmapFromURL(String src) {
Bitmap bmImg;
URL myFileUrl = null;
try {
myFileUrl = new URL(src);
HttpURLConnection conn= (HttpURLConnection)myFileUrl.openConnection();
conn.setDoInput(true);
conn.connect();
InputStream is = conn.getInputStream();
final BitmapFactory.Options options = new BitmapFactory.Options();
BufferedInputStream bis = new BufferedInputStream(is, 4*1024);
ByteArrayBuffer baf = new ByteArrayBuffer(50);
int current = 0;
while ((current = bis.read()) != -1) {
baf.append((byte)current);
}
byte[] imageData = baf.toByteArray();
BitmapFactory.decodeByteArray(imageData, 0, imageData.length, options);
options.inJustDecodeBounds = true;
options.inSampleSize = calculateInSampleSize(options, 1024, 128);
options.inJustDecodeBounds = false;
Bitmap bitmap = BitmapFactory.decodeByteArray(imageData, 0, imageData.length,options);
return bitmap;
} catch (Exception e) {
// TODO Auto-generated catch block
return null;
}
}
和
public static int calculateInSampleSize(
BitmapFactory.Options options, int reqWidth, int reqHeight) {
// Raw height and width of image
// Raw height and width of image
final int height = options.outHeight;
final int width = options.outWidth;
int inSampleSize = 1;
if (height > reqHeight || width > reqWidth) {
final int halfHeight = height / 2;
final int halfWidth = width / 2;
// Calculate the largest inSampleSize value that is a power of 2 and keeps both
// height and width larger than the requested height and width.
while ((halfHeight / inSampleSize) > reqHeight
&& (halfWidth / inSampleSize) > reqWidth) {
inSampleSize *= 2;
}
}
return inSampleSize;
}
异步任务类
class BitmapWorkerTask extends AsyncTask<String, Void, Bitmap> {
private final WeakReference<ImageView> imageViewReference;
private String data = null;
public BitmapWorkerTask(ImageView imageView) {
// Use a WeakReference to ensure the ImageView can be garbage collected
imageViewReference = new WeakReference<ImageView>(imageView);
}
// Decode image in background.
@Override
protected Bitmap doInBackground(String... params) {
data = params[0];
return Util.getBitmapFromURL(data);
}
// Once complete, see if ImageView is still around and set bitmap.
@Override
protected void onPostExecute(Bitmap bitmap) {
if (imageViewReference != null && bitmap != null) {
final ImageView imageView = imageViewReference.get();
if (imageView != null) {
imageView.setImageBitmap(Bitmap.createBitmap(bitmap, 0, bitmap.getHeight()/2, bitmap.getWidth(), bitmap.getHeight()/2));
}
}
}
}
当我在 Nexus 上运行时,出现内存不足异常。在关注 android 开发者网站时,我不明白我在这里做错了什么以及为什么我的应用程序在旧设备中崩溃。请帮忙。
注意:我的图像宽度应始终为 match_parent。这就是为什么我把 calculateInSampleSize(option, 1024 ,128)