blocks|key|709099|text|您好，这是null，因为可能是图像大小和得到异常，请检查您的日志，看看是否有任何错误的输出内存位图，如果是，然后使用选项：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|709100|BitmapFactory.Options+options;

try+{
++String+imageInSD+=+"/sdcard/UserImages/"+%2B+userImageName;
++Bitmap+bitmap+=+BitmapFactory.decodeFile(imageInSD);
++return+bitmap;
}+catch+(OutOfMemoryError+e)+{
++try+{
++++options+=+new+BitmapFactory.Options();
++++options.inSampleSize+=+2;
++++Bitmap+bitmap+=+BitmapFactory.decodeFile(imageInSD,+null,+options);
++++return+bitmap;
++}+catch(Exception+excepetion)+{
++++Log.e(excepetion);
++}
}|code-block|syntax|javascript|709101|entityMap^0|5|4|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

Hi it is <code>null</code> because may be the image size is big and getting exception please check your log and see is there any error of outofmemory bitmap if yes then use options for that:

<pre><code>BitmapFactory.Options options;

try {
 String imageInSD = "/sdcard/UserImages/" + userImageName;
 Bitmap bitmap = BitmapFactory.decodeFile(imageInSD);
 return bitmap;
} catch (OutOfMemoryError e) {
 try {
 options = new BitmapFactory.Options();
 options.inSampleSize = 2;
 Bitmap bitmap = BitmapFactory.decodeFile(imageInSD, null, options);
 return bitmap;
 } catch(Exception excepetion) {
 Log.e(excepetion);
 }
}
</code></pre>

blocks|key|493397|text|尝试添加SD卡访问权限READ_EXTERNAL_STORAGE和/或WRITE_EXTERNAL_STORAGE。这对我很管用。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|493398|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Try to add SD card access permissions READ_EXTERNAL_STORAGE and/or WRITE_EXTERNAL_STORAGE.
It works for me.

blocks|key|709438|text|如果您正尝试在Android10中尝试在清单android:requestLegacyExternalStorage="true"中将其添加到您的应用程序中，这可能是Android10的权限问题，因为它不允许直接访问文件|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|709439|entityMap^0|M|17|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

if you are trying in android 10 try adding this to your application in manifest
<code>android:requestLegacyExternalStorage=&quot;true&quot;</code> it may be a permission issue with android 10 since it doesn't allow direct access to files

blocks|key|709186|text|我错过了API级别大于22的运行时权限检查。启动Marshmellow|type|unstyled|depth|inlineStyleRanges|entityRanges|data|709187|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

I was missing run time permission check on API level greater than 22. Starting Marshmellow

blocks|key|709516|text|我的解决方案是在清单的Application标签中添加下面提到的属性：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|709517|Android:requestLegacyExternalStorage+=+"true"|code-block|syntax|javascript|709518|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

My solution was to add the below-mentioned property in the manifest's Application tag:
<pre><code>Android:requestLegacyExternalStorage = &quot;true&quot;
</code></pre>

blocks|key|709244|text|在将整个图像放入该路径之前，BitmapFactory.decodeFile()将执行。当decodeFile()执行时，没有图像。因此，位图返回null。通常，高像素图像需要花费一些额外的时间来放置在它们的路径中。所以这个异常就发生了。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|709245|请检查空值并尝试decodeFile。|709246|Bitmap+bitmap+=+null;

while(bitmap+==+null)
+++bitmap+=+BitmapFactory.decodeFile(imageInSD);|code-block|syntax|javascript|709247|entityMap^0|E|Q|19|C|21|4|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]|$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|V|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|W|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|X|8|@]|D|@]|E|$]]]|N|$]]

The <code>BitmapFactory.decodeFile()</code> executes before the entire image placing in that exact path. When <code>decodeFile()</code> executes there is no image. So the bitmap returns <code>null</code>. Generally the high pixel images takes some extra time to place in their path. So this exception happens.

Please check the null and try to decodeFile.

<pre><code>Bitmap bitmap = null;

while(bitmap == null)
 bitmap = BitmapFactory.decodeFile(imageInSD);
</code></pre>

blocks|key|709305|text|我正在构建一个图像处理应用程序，并且在尝试这些方法时也返回了null。我的控制台返回的不是错误，而是如下所示的degub语句|type|unstyled|depth|inlineStyleRanges|entityRanges|data|709306|D/skia：-解码器->解码返回false|709307|下面是我发现的将在整个应用程序中加载任何位图的内容|709308|1)正确的文件名和适当的权限|709309|2)适当时缩小图像|709310|3)如果您需要一个大图像，请将其设置在您的清单下，如下所示|709311|+<application

++++android:largeHeap="true"

</application>|code-block|syntax|javascript|709312|使用大堆并不能替代显示正确的图像大小。下面是我直接从androids+docs中使用的代码示例|offset|length|709313|+public+Bitmap+getRawImageThumb(Context+mContext)
{
++++Bitmap+b+=+null;

++++int+reqHeight+=+100,+reqWidth+=+100;

++++String+filename+=+mContext.getFilesDir().toString()+%2B+"/"+%2B+rawFileName;
++++Log.d(TAG,+"processRawReceipt:+"+%2B+rawFileName);


++++BitmapFactory.Options+options+=+new+BitmapFactory.Options();
++++options.inJustDecodeBounds+=+true;
++++//options.inPreferredConfig+=+Bitmap.Config.ARGB_8888;
++++BitmapFactory.decodeFile(filename,+options);
++++int+height+=+options.outHeight;
++++int+width+=+options.outWidth;


++++int+inSampleSize+=+1;

++++if+(height+>+reqHeight+%7C%7C+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;
++++++++}
++++}

++++options.inSampleSize+=+inSampleSize;
++++options.inJustDecodeBounds+=+false;
++++Log.d(TAG,+"getRawImage:+"+%2B+String.valueOf(height)+%2B+"+"++%2B+String.valueOf(width)+%2B+"+"+%2B+String.valueOf(inSampleSize));
++++b+=+BitmapFactory.decodeFile(filename,+options);

++++return+b;
}|709314|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.android.com/topic/performance/graphics/load-bitmap^0|0|0|0|0|0|0|0|Q|D|0|0|0^^$0|@$1|2|3|4|5|6|7|14|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|15|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|16|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|17|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|18|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|19|8|@]|9|@]|A|$]]|$1|L|3|M|5|N|7|1A|8|@]|9|@]|A|$O|P]]|$1|Q|3|R|5|6|7|1B|8|@]|9|@$S|1C|T|1D|1|1E]]|A|$]]|$1|U|3|V|5|N|7|1F|8|@]|9|@]|A|$O|P]]|$1|W|3|-4|5|6|7|1G|8|@]|9|@]|A|$]]]|X|$Y|$5|Z|10|11|A|$12|13]]]]

I'm building an image processing app and have also returned null when trying these methods. My console returned not an error but a degub statement like this

D/skia: --- decoder->decode returned false

Here is what I found that will get any bitmap to load throughout my application

1) correct file name with appropriate permissions

2) Scale image down when appropriate

3) If you need a large image set it under you manifest like so

<pre><code> &lt;application

 android:largeHeap="true"

&lt;/application&gt;
</code></pre>

Using a large heap is not a substitute for displaying the correct image size. Here is an example of the code I use directly from <a href="https://developer.android.com/topic/performance/graphics/load-bitmap" rel="nofollow noreferrer">androids docs</a> 

<pre><code> public Bitmap getRawImageThumb(Context mContext)
{
 Bitmap b = null;

 int reqHeight = 100, reqWidth = 100;

 String filename = mContext.getFilesDir().toString() + "/" + rawFileName;
 Log.d(TAG, "processRawReceipt: " + rawFileName);


 BitmapFactory.Options options = new BitmapFactory.Options();
 options.inJustDecodeBounds = true;
 //options.inPreferredConfig = Bitmap.Config.ARGB_8888;
 BitmapFactory.decodeFile(filename, options);
 int height = options.outHeight;
 int width = options.outWidth;


 int inSampleSize = 1;

 if (height &gt; reqHeight || width &gt; 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) &gt;= reqHeight
 &amp;&amp; (halfWidth / inSampleSize) &gt;= reqWidth) {
 inSampleSize *= 2;
 }
 }

 options.inSampleSize = inSampleSize;
 options.inJustDecodeBounds = false;
 Log.d(TAG, "getRawImage: " + String.valueOf(height) + " " + String.valueOf(width) + " " + String.valueOf(inSampleSize));
 b = BitmapFactory.decodeFile(filename, options);

 return b;
}
</code></pre>

blocks|key|709366|text|如果有，请删除"options.inJustDecodeBounds+=+true;"|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|709367|++val+options+=++BitmapFactory.Options();
++//options.inJustDecodeBounds+=+true;+//delete+this+line
++var+bitmap+=+BitmapFactory.decodeFile(file.getAbsolutePath(),+options);|code-block|syntax|javascript|709368|entityMap^0|7|10|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

Delete <code>"options.inJustDecodeBounds = true;"</code> if you have

<pre><code> val options = BitmapFactory.Options();
 //options.inJustDecodeBounds = true; //delete this line
 var bitmap = BitmapFactory.decodeFile(file.getAbsolutePath(), options);
</code></pre>

When I am calling this function there is no image in image view 
<code>bitmapFactory.decodefile(filename)</code> showing null .. please help for this.

Here is my code :

<pre><code>public Bitmap ShowImage(String imageName,String userImageName ) 
{

 File sdcard_mainDirectory = new File(Environment.getExternalStorageDirectory(),"UserImages").getAbsoluteFile();

 File file = new File(sdcard_mainDirectory, userImageName).getAbsoluteFile();

 if (file != null) {

 try {

 String imageInSD = "/sdcard/UserImages/"+userImageName;

 Bitmap bitmap = BitmapFactory.decodeFile(imageInSD);

 return bitmap;

 }
 catch (Exception e) {

 e.printStackTrace();
 }

 }

 return null;

}
</code></pre>

Bitmap is returning null from BitmapFactory.decodeFile(filename)

图像处理

Android

当我调用此函数时，图像视图bitmapFactory.decodefile(filename)中没有图像显示为null。请帮帮忙。下面是我的代码：public Bitmap ShowImage(String imageName,String userImageName ) {    File sdcard_mainDirectory = new File(Environment.getExtern

问位图从BitmapFactory.decodeFile(文件名)返回null
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回答 8

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问位图从BitmapFactory.decodeFile(文件名)返回null
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