Java 在Android中加载大图像
众所周知,Android在RAM内存中存储位图数据时存在问题。我需要在视图上加载一张图像(来自13Mpx相机的照片),然后我需要能够放大和缩小图像。图像应该是可变的。现在是这样实施的:Java 在Android中加载大图像,java,android,image,Java,Android,Image,众所周知,Android在RAM内存中存储位图数据时存在问题。我需要在视图上加载一张图像(来自13Mpx相机的照片),然后我需要能够放大和缩小图像。图像应该是可变的。现在是这样实施的: BitmapFactory.Options options = new BitmapFactory.Options(); options.inMutable = true; _bitmap = BitmapFactory.decodeFile(_path, options); 当我拍摄一张大照片(13或8 M
BitmapFactory.Options options = new BitmapFactory.Options();
options.inMutable = true;
_bitmap = BitmapFactory.decodeFile(_path, options);
当我拍摄一张大照片(13或8 Mpx)时,程序因“内存不足”错误而崩溃。我需要一些解决这个问题的办法。我需要一些类,可以加载和操作(缩放它)与大图像。它需要等于或小于API-8
我尝试了Universall图像加载程序,但它没有缩放选项。有人知道如何解决这个问题吗?我建议使用Square的library。用于图像缩放。我建议使用Square中的library。用于图像缩放。尝试此方法缩放位图
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
/*
* If set to a value > 1, requests the decoder to
* subsample the original image, returning a smaller
* image to save memory. The sample size is the
* number of pixels in either dimension that
* correspond to a single pixel in the decoded
* bitmap. For example, inSampleSize == 4 returns an
* image that is 1/4 the width/height of the
* original, and 1/16 the number of pixels. Any
* value <= 1 is treated the same as 1. Note: the
* decoder uses a final value based on powers of 2,
* any other value will be rounded down to the
* nearest power of 2.
*/
options.inSampleSize = 2;
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
bitmap = BitmapFactory.decodeFile(path, options);
final BitmapFactory.Options=new BitmapFactory.Options();
options.inJustDecodeBounds=true;
/*
*如果设置为大于1的值,则请求解码器
*对原始图像进行子采样,返回较小的
*图像以节省内存。样本量为
*任意维度中的像素数
*对应于解码图像中的单个像素
*位图。例如,inSampleSize==4返回一个
*图像的宽度/高度为图像宽度/高度的1/4
*原始,1/16像素数。任何
*值尝试此方法缩放位图
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
/*
* If set to a value > 1, requests the decoder to
* subsample the original image, returning a smaller
* image to save memory. The sample size is the
* number of pixels in either dimension that
* correspond to a single pixel in the decoded
* bitmap. For example, inSampleSize == 4 returns an
* image that is 1/4 the width/height of the
* original, and 1/16 the number of pixels. Any
* value <= 1 is treated the same as 1. Note: the
* decoder uses a final value based on powers of 2,
* any other value will be rounded down to the
* nearest power of 2.
*/
options.inSampleSize = 2;
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
bitmap = BitmapFactory.decodeFile(path, options);
final BitmapFactory.Options=new BitmapFactory.Options();
options.inJustDecodeBounds=true;
/*
*如果设置为大于1的值,则请求解码器
*对原始图像进行子采样,返回较小的
*图像以节省内存。样本量为
*任意维度中的像素数
*对应于解码图像中的单个像素
*位图。例如,inSampleSize==4返回一个
*图像的宽度/高度为图像宽度/高度的1/4
*原始,1/16像素数。任何
*值位图每像素占用4字节==>13MP等于52MB内存。
您应该首先使用BitmapFactory.Options来获取大小。通过使用inJustDecodeBounds
可以获得位图对象及其所有元数据,但没有实际图像
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeResource(getResources(), R.id.myimage, options);
int imageHeight = options.outHeight;
int imageWidth = options.outWidth;
然后计算屏幕所需的比例大小:
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) {
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;
}
并使用它加载位图的缩放版本:
public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId,
int reqWidth, int reqHeight) {
// First decode with inJustDecodeBounds=true to check dimensions
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeResource(res, resId, options);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
return BitmapFactory.decodeResource(res, resId, options);
}
这一切都在中解释过,位图每像素占用4字节==>13MP等于52MB内存。
您应该首先使用BitmapFactory.Options来获取大小。通过使用inJustDecodeBounds
可以获得位图对象及其所有元数据,但没有实际图像
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeResource(getResources(), R.id.myimage, options);
int imageHeight = options.outHeight;
int imageWidth = options.outWidth;
然后计算屏幕所需的比例大小:
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) {
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;
}
并使用它加载位图的缩放版本:
public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId,
int reqWidth, int reqHeight) {
// First decode with inJustDecodeBounds=true to check dimensions
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeResource(res, resId, options);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
return BitmapFactory.decodeResource(res, resId, options);
}
这些都在报告中解释过了
要避免java.lang.OutOfMemory
异常,请在解码位图之前检查位图的尺寸,除非您完全信任源为您提供可预测大小的图像数据,这些数据可以轻松地放入可用内存中
要避免java.lang.OutOfMemory
异常,请在解码位图之前检查位图的尺寸,除非您完全信任源为您提供可预测大小的图像数据,这些数据可以轻松地放入可用内存中 非常感谢大家给了我们所有的答案
我认为我应该使用inJustDecodeBounds选项并加载调整大小的位图,但需要有经验的人对这个问题有一个新的看法
我还考虑使用Universal Image Loader加载和缓存大型图像,以及使用ScaleImageView之类的工具进行缩放
有一种方法可以解决我的问题。部分加载位图 非常感谢大家给了我们所有的答案
我认为我应该使用inJustDecodeBounds选项并加载调整大小的位图,但需要有经验的人对这个问题有一个新的看法
我还考虑使用Universal Image Loader加载和缓存大型图像,以及使用ScaleImageView之类的工具进行缩放
有一种方法可以解决我的问题。部分加载位图 可能的重复可能的重复