What is .9.png?
The picture of .9.png format is the particular picture format of android, it is neither simply rename the png picture .9.png, nor repeat your picture; it can be stretched without audible distortion, you can stretch it magically to the specified location.
The exact difference of .9.png from others is that compared with normal png pictures, .9.png picture is surrounded by an extra 1px blank area which can only be seen in picture production and preservation process, and not be seen in the running process. And the overall pixel of the picture will reduce 2px, for instance, a picture of 44*44px will become 46*46px when it is made .9.png picture, in the process of packaging and running you can only see 44*44, so you must pay attention the size of the picture in the production process.
Produce .9.png picture.
Step 1, Download tool: draw9patch.zip
You must install JDK first, and make sure whether your system is 32bit or 64bit when downloading.
Step 5, Draw a stretch area and save it, it will be automatically saved as the .9.png format.
In this way, the .9.png picture is finished, the original 44*44px picture is turned to .9.png picture of 46*46px, because there is an extra 1px blank area around which is used to draw the black line in the stretch area, and the black line will not be seen when the system is running.
Anyone is welcomed to redistribute and quote the content only if he or she notes its origin. http://4-designer.com/2013/10/gui-produce-the-android-9-png-picture