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我从 javaCameraView 加载位图中的图像。这是发送到异步任务以便将其发送到 php 文件。在第一秒没有问题。在这段时间之后，我遇到了线程问题，但我没有找到解决方案。这是 LogCat ：

    07-25 16:36:29.492: E/AndroidRuntime(17507): FATAL EXCEPTION: AsyncTask #5
    07-25 16:36:29.492: E/AndroidRuntime(17507): java.lang.RuntimeException: An error occured while executing doInBackground()
    07-25 16:36:29.492: E/AndroidRuntime(17507):    at   android.os.AsyncTask$3.done(AsyncTask.java:299)
    07-25 16:36:29.492: E/AndroidRuntime(17507):    at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
    07-25 16:36:29.492: E/AndroidRuntime(17507):    at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
    07-25 16:36:29.492: E/AndroidRuntime(17507):    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
    07-25 16:36:29.492: E/AndroidRuntime(17507):    at java.util.concurrent.FutureTask.run(FutureTask.java:137)
    07-25 16:36:29.492: E/AndroidRuntime(17507):    at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
    07-25 16:36:29.492: E/AndroidRuntime(17507):    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
    07-25 16:36:29.492: E/AndroidRuntime(17507):    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
    07-25 16:36:29.492: E/AndroidRuntime(17507):    at java.lang.Thread.run(Thread.java:856)
    07-25 16:36:29.492: E/AndroidRuntime(17507): Caused by: java.lang.OutOfMemoryError
    07-25 16:36:29.492: E/AndroidRuntime(17507):    at java.lang.String.<init>(String.java:375)
    07-25 16:36:29.492: E/AndroidRuntime(17507):    at java.lang.String.<init>(String.java:238)
    07-25 16:36:29.492: E/AndroidRuntime(17507):    at android.util.Base64.encodeToString(Base64.java:456)
    07-25 16:36:29.492: E/AndroidRuntime(17507):    at com.example.objectDetect.SendData.getStringFromBitmap(SendData.java:186)
    07-25 16:36:29.492: E/AndroidRuntime(17507):    at com.example.objectDetect.SendData.doInBackground(SendData.java:63)
    07-25 16:36:29.492: E/AndroidRuntime(17507):    at com.example.objectDetect.SendData.doInBackground(SendData.java:1)
    07-25 16:36:29.492: E/AndroidRuntime(17507):    at android.os.AsyncTask$2.call(AsyncTask.java:287)
    07-25 16:36:29.492: E/AndroidRuntime(17507):    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
    07-25 16:36:29.492: E/AndroidRuntime(17507):    ... 5 more

我认为问题出在这个函数上，但我不知道为什么：

private String getStringFromBitmap(Bitmap bitmapPicture)
{
     if(!bitmapPicture.isRecycled())
     {
         final int COMPRESSION_QUALITY = 100;
         String encodedImage;
         ByteArrayOutputStream byteArrayBitmapStream = new ByteArrayOutputStream();
         bitmapPicture.compress(Bitmap.CompressFormat.PNG, COMPRESSION_QUALITY, byteArrayBitmapStream);
         byte[] b = byteArrayBitmapStream.toByteArray();
         encodedImage = Base64.encodeToString(b, Base64.DEFAULT);
         return encodedImage;
     }
     else
     {
         return null;
     }
}

经过大量测试，我有一个不同的 logcat，但它总是内存问题。我在运行函数的线程中创建了一个位图。

在 logcat 下方：

    07-26 09:42:50.491: E/AndroidRuntime(31291): FATAL EXCEPTION: Thread-27487
    07-26 09:42:50.491: E/AndroidRuntime(31291): java.lang.OutOfMemoryError
    07-26 09:42:50.491: E/AndroidRuntime(31291):    at android.graphics.Bitmap.nativeCreate(Native Method)
    07-26 09:42:50.491: E/AndroidRuntime(31291):    at android.graphics.Bitmap.createBitmap(Bitmap.java:640)
    07-26 09:42:50.491: E/AndroidRuntime(31291):    at android.graphics.Bitmap.createBitmap(Bitmap.java:620)
    07-26 09:42:50.491: E/AndroidRuntime(31291):    at com.example.objectDetection.objectDetectionView$1.run(objectDetectionView.java:197)

预先感谢您的帮助。

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1 回答 1

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下面的代码是我想出的，以避免加载位图时出现内存不足错误。

   private Bitmap loadImageFromNetwork(String urlToUse) {
    Bitmap img = null;
    URL url;
    try {
       //A uniform resource locator aka the place where the data is       
       //located
       url = new URL(urlToUse);
       //Opens an HTTPUrlConnection and downloads the input stream into a
       //Bitmap
       final BitmapFactory.Options options = new BitmapFactory.Options();
       // Prevents loading of image into memory and just ascertains bounds and memory footprint
       options.inJustDecodeBounds = true;

       BitmapFactory.decodeStream(url.openStream(),null,options); // gather image data
       options.inSampleSize = Photo.calculateInSampleSize(options, 
               Photo.THUMBNAIL_WIDTH, Photo.THUMBNAIL_HEIGHT);
       options.inJustDecodeBounds = false;
       img = BitmapFactory.decodeStream(url.openStream(),null,options);

    } catch (MalformedURLException e) {
       Log.i("PAR", "URL is malformed");
       e.printStackTrace();
    } catch (IOException e) {
       Log.i("PAR", "Failed to decode Bitmap");
       e.printStackTrace();
    }

    return img;

} // end load function


public static int calculateInSampleSize(
    BitmapFactory.Options options, int reqWidth, int reqHeight) {
    // Raw height and width of image
    final int height = options.outHeight;
    final int width = options.outWidth;
    int inSampleSize = 1;

    if (height > reqHeight || width > reqWidth) {
        if (width > height) {
            inSampleSize = Math.round((float)height / (float)reqHeight);
        } else {
            inSampleSize = Math.round((float)width / (float)reqWidth);
        } // end if
    } // end out if
    return inSampleSize;
}

这里要确定的关键是初始加载不包括整个图像。inJustDecodeBounds 标志设置为 true，这与听起来完全一样。它只解码边界，因此您可以提前确定图像是否太大。我的建议是确定边界和其他相关数据，然后在加载所有图像之前进行调整。对于此示例，我将大图像转换为缩略图。

使用此技术应在压缩图像之前减小图像大小。我想权衡是您正在减少加载图像，这可能意味着质量较低。但是，如果您的内存不足，如果您愿意稍微缩小图像，这可能是一个可行的选择。

于 2013-07-25T15:20:26.877 回答