improving ndk installer script

scripts/install_android_ndk.sh

@@ -1,12 +1,18 @@
 #!/bin/bash
 
+project_dir=${OLDPWD}
 local_opt_dir="${HOME}/.local/opt"
 
 ndk_name="android-ndk-r10e"
 ndk_install_dest="${local_opt_dir}/${ndk_name}"
 
-if [ -d ${ndk_install_dest} ];
-    then exit
+if [ -d ${ndk_install_dest} ]; then
+    echo "NDK already installed in ${ndk_install_dest}"
+    exit
+fi
+
+if [ ! -d ${local_opt_dir} ]; then
+    mkdir -p ${local_opt_dir}
 fi
 
 cd ${local_opt_dir}
@@ -19,12 +25,20 @@ else
     ndk_installer_name="${ndk_name}-linux-x86.bin"
 fi
 
+echo "Downloading NDK installer ${ndk_installer_name}"
+
 wget "http://dl.google.com/android/ndk/${ndk_installer_name}"
 
 chmod +x ${ndk_installer_name}
 
+echo "Installing NDK installer ${ndk_installer_name}"
+
 ./${ndk_installer_name} -y 1>/dev/null
 
+echo "Removing installed NDK installer ${ndk_installer_name}"
+
 rm ${ndk_installer_name}
 
-echo "ndk.dir=${ndk_install_dest}" >> ./local.properties
+echo "Adding NDK install path to ${project_dir}"
+
+echo "ndk.dir=${ndk_install_dest}" >> ${project_dir}/local.properties