Java 可从android中的URL有限内存中提取

我想从URL获取图像并将其转换为可绘制的。我有这个方法，效果很好：

public static Drawable getDrawableFromUrl(String url) throws IOException {
    Bitmap x;

    HttpURLConnection connection = (HttpURLConnection) new URL(url).openConnection();
    connection.connect();
    InputStream input = connection.getInputStream();

    x = BitmapFactory.decodeStream(input);
    return new BitmapDrawable(x);
}

除了一件事。当图像太大时，应用程序崩溃

E/dalvikvm-heap(12750): 13142360-byte external allocation too large for this process.
E/dalvikvm(12750): Out of memory: Heap Size=6023KB, Allocated=3177KB, Bitmap Size=2563KB, Limit=20480KB
E/dalvikvm(12750): Trim info: Footprint=6023KB, Allowed Footprint=6023KB, Trimmed=952KB
E/GraphicsJNI(12750): VM won't let us allocate 13142360 bytes

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我是否可以增加图像所需的内存？或者有办法解决这个问题？

我建议您将文件临时保存在手机上，然后阅读并将其用作绘图工具。但是，如果手机无法加载图像，则您需要从发件人处缩小图像的比例，或者在打开图像之前缩小图像的比例。

我建议您将该文件临时保存在手机上，然后将其读取并用作绘图文件。但是，如果手机无法加载图像，则您需要缩小发件人的图像或在打开图像之前缩小图像。

上面的链接从url返回重新调整大小的位图，然后您可以转换为位图可绘制

从该链接下载并使用位图趣味示例应用程序。

上面的链接从url返回重新调整大小的位图，然后您可以转换为位图可绘制

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从该链接下载并使用位图趣味示例应用程序。

您需要按照此链接的建议缩小图像的比例或调整其大小

以下是一些用于此的代码片段：

    public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId,
        int reqWidth, int reqHeight) {

    final BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    BitmapFactory.decodeResource(res, resId, options);
    options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
    options.inJustDecodeBounds = false;
    return BitmapFactory.decodeResource(res, resId, options);
}

public static int calculateInSampleSize(
        BitmapFactory.Options options, int reqWidth, int reqHeight) {
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);
    }
}
return inSampleSize;
}

当你设定你的可画性时，只需调用这个部分

MyImageview.setImageBitmap(decodeSampledBitmapFromResource(getResources(), mydrawable, 420, 620));

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您需要按此链接的建议缩小图像或调整其大小

以下是一些用于此的代码片段：

    public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId,
        int reqWidth, int reqHeight) {

    final BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    BitmapFactory.decodeResource(res, resId, options);
    options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
    options.inJustDecodeBounds = false;
    return BitmapFactory.decodeResource(res, resId, options);
}

public static int calculateInSampleSize(
        BitmapFactory.Options options, int reqWidth, int reqHeight) {
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);
    }
}
return inSampleSize;
}

当你设定你的可画性时，只需调用这个部分

MyImageview.setImageBitmap(decodeSampledBitmapFromResource(getResources(), mydrawable, 420, 620));

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嗯。下面是最终有效的代码。 正如我建议的那样，我使用给定的函数来缩小图像的大小：calculateInSampleSize-thx Androyds

public static Drawable getDrawableFromUrl(String url, Context context) throws IOException {
    Bitmap x;

    HttpURLConnection connection = (HttpURLConnection) new URL(url).openConnection();
    connection.connect();
    InputStream inputStream = connection.getInputStream();
    BufferedInputStream bufferedInputStream = new BufferedInputStream(inputStream);

    BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
bufferedInputStream.mark(connection.getContentLength());
BitmapFactory.decodeStream(bufferedInputStream, null, options);
bufferedInputStream.reset();

options.inJustDecodeBounds = false;
options.inSampleSize = calculateInSampleSize(options, 400, 400);

x = BitmapFactory.decodeStream(bufferedInputStream, null, options);

bufferedInputStream.close();
connection.disconnect();

    BitmapDrawable y = new BitmapDrawable(x);

    return y;
}

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嗯。下面是最终有效的代码。 正如我建议的那样，我使用给定的函数来缩小图像的大小：calculateInSampleSize-thx Androyds

public static Drawable getDrawableFromUrl(String url, Context context) throws IOException {
    Bitmap x;

    HttpURLConnection connection = (HttpURLConnection) new URL(url).openConnection();
    connection.connect();
    InputStream inputStream = connection.getInputStream();
    BufferedInputStream bufferedInputStream = new BufferedInputStream(inputStream);

    BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
bufferedInputStream.mark(connection.getContentLength());
BitmapFactory.decodeStream(bufferedInputStream, null, options);
bufferedInputStream.reset();

options.inJustDecodeBounds = false;
options.inSampleSize = calculateInSampleSize(options, 400, 400);

x = BitmapFactory.decodeStream(bufferedInputStream, null, options);

bufferedInputStream.close();
connection.disconnect();

    BitmapDrawable y = new BitmapDrawable(x);

    return y;
}

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对不起，到目前为止，我是一个java noob。我如何称呼它：MyImageview.setImageBitmap（decodeSampledBitmapFromResource（getResources（），mydrawable，420620））；在我的getDrawableFromUrl（字符串url）函数中？@baron_bartek您是否试图从url获取图像？是的。我终于有了基于函数的代码。请看我的衣服。对不起，到目前为止我是一个java noob。我如何称呼它：MyImageview.setImageBitmap（decodeSampledBitmapFromResource（getResources（），mydrawable，420620））；在我的getDrawableFromUrl（字符串url）函数中？@baron_bartek您是否试图从url获取图像？是的。我终于有了基于函数的代码。请看我的衣服。