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<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>In GDAL 1.8.1 I’m attempting to call GetMetadataItem()
within the context of an Android 2.2 Java app, but I’m getting an error,
specifically<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>08-10 22:13:41.750: WARN/dalvikvm(546): JNI WARNING: jstring
0x40569100 points to non-string object (Check_GetStringUTFChars)<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>An access violation error follows this.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I’ve successfully opened the image and have a valid
Dataset object. I’ve debugged my way through the JPIPKAKDataset
initialization method so I’m pretty confident that much is working
properly.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I don’t know if this is a problem with the swig
bindings or something else. I hope someone’s run into this one
before.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>My Java code is really straightforward:<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 color=black
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:black'> </span></font><b><font size=2
color="#7f0055" face="Courier New"><span style='font-size:10.0pt;font-family:
"Courier New";color:#7F0055;font-weight:bold'>public</span></font></b><font
size=2 color=black face="Courier New"><span style='font-size:10.0pt;font-family:
"Courier New";color:black'> </span></font><b><font size=2 color="#7f0055"
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:#7F0055;font-weight:bold'>int</span></font></b><font size=2 color=black
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:black'> getDecompositionLevels() {</span></font><font size=2
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 color=black
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:black'> </span></font><b><font
size=2 color="#7f0055" face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New";color:#7F0055;font-weight:bold'>if</span></font></b><font
size=2 color=black face="Courier New"><span style='font-size:10.0pt;font-family:
"Courier New";color:black'> (</span></font><font size=2 color="#0000c0"
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:#0000C0'>gdalDataset</span></font><font size=2 color=black
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:black'> != </span></font><b><font size=2 color="#7f0055"
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:#7F0055;font-weight:bold'>null</span></font></b><font size=2 color=black
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:black'>)</span></font><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 color=black
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:black'> {</span></font><font
size=2 face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 color=black
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:black'> String
key = </span></font><font size=2 color="#2a00ff" face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:#2A00FF'>"JPIP_NRESOLUTIONLEVELS"</span></font><font
size=2 color=black face="Courier New"><span style='font-size:10.0pt;font-family:
"Courier New";color:black'>;</span></font><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 color=black
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:black'> String
domain = </span></font><font size=2 color="#2a00ff" face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:#2A00FF'>"JPIP"</span></font><font
size=2 color=black face="Courier New"><span style='font-size:10.0pt;font-family:
"Courier New";color:black'>;</span></font><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 color=black
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:black'> </span></font><b><font
size=2 color="#7f0055" face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New";color:#7F0055;font-weight:bold'>return</span></font></b><font
size=2 color=black face="Courier New"><span style='font-size:10.0pt;font-family:
"Courier New";color:black'> Integer.<i><span style='font-style:italic'>parseInt</span></i>(</span></font><font
size=2 color="#0000c0" face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New";color:#0000C0'>gdalDataset</span></font><font size=2
color=black face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:black'>.GetMetadataItem(key, domain));</span></font><font size=2
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 color=black
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:black'> }
</span></font><b><font size=2 color="#7f0055" face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:#7F0055;font-weight:
bold'>else</span></font></b><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:black'> {</span></font><font
size=2 face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 color=black
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:black'> </span></font><b><font
size=2 color="#7f0055" face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New";color:#7F0055;font-weight:bold'>return</span></font></b><font
size=2 color=black face="Courier New"><span style='font-size:10.0pt;font-family:
"Courier New";color:black'> -1;</span></font><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 color=black
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:black'> }</span></font><font
size=2 face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 color=black
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:black'> }</span></font><font size=2
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>This corresponds to the API definition found here:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>http://gdal.org/java/org/gdal/gdal/MajorObject.html#GetMetadataItem(java.lang.String,
java.lang.String)<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I’ve also tried the variant that uses a default domain
string with the same error as a result.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I’m using the gdal_wrap.cpp generated in the swig/java
directory along with corresponding gdal.jar file.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>The org.gdal.gdal.MajorObject.java class defines the interface
as<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 color=black
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:black'> </span></font><b><font size=2 color="#7f0055"
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:#7F0055;font-weight:bold'>public</span></font></b><font size=2
color=black face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:black'> String GetMetadataItem(String pszName, String pszDomain) {</span></font><font
size=2 face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 color=black
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:black'> </span></font><b><font size=2 color="#7f0055"
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:#7F0055;font-weight:bold'>return</span></font></b><font size=2
color=black face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:black'> gdalJNI.<i><span style='font-style:italic'>MajorObject_GetMetadataItem__SWIG_0</span></i>(</span></font><font
size=2 color="#0000c0" face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New";color:#0000C0'>swigCPtr</span></font><font size=2
color=black face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:black'>, </span></font><b><font size=2 color="#7f0055" face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:#7F0055;font-weight:
bold'>this</span></font></b><font size=2 color=black face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:black'>, pszName,
pszDomain);</span></font><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 color=black
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:black'> }</span></font><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>The swig interface file MajorObject.i defines this as<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>/*<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> * GetMetadataItem<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> */<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> %apply Pointer NONNULL {const char * pszName};<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> const char *GetMetadataItem( const char *pszName,
const char *pszDomain = "" ) {<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> return GDALGetMetadataItem( self,
pszName, pszDomain);<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> }<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>While the generated gdal_wrap.cpp is<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>SWIGINTERN char const
*GDALMajorObjectShadow_GetMetadataItem__SWIG_0(GDALMajorObjectShadow *self,char
const *pszName,char const *pszDomain=""){<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> return GDALGetMetadataItem( self,
pszName, pszDomain);<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-indent:6.0pt'><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial'>}<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-indent:6.0pt'><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I’ve found a thread discussing a similar issue under
the android-ndk group, but without the swig component:<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-indent:6.0pt'><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>http://groups.google.com/group/android-ndk/browse_thread/thread/27e83cdf168bc0bb/db151ea4c15362c5?show_docid=db151ea4c15362c5<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I infer from that discussion that either the GDAL interface
definition file needs to be tweaked or I need to use javah instead of swig.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I’m still new to all of this (including GDAL) so
assume I’m missing something blatantly obvious.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Thanks for any help,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Jim P.<o:p></o:p></span></font></p>
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