Question

我需要从drawable文件夹外部加载9-patch文件。这样我的应用程序就可以从服务器下载新的皮肤。我发现在制作.apk时会编译存储在drawable文件夹中的9补丁图像。从assets文件夹读取的完全相同的文件没有9补丁块。因此，制作.apk的行为是在可绘制文件夹中编译源9补丁文件，但不在资源目录中编译。

如何自己编译9补丁文件，以便将其安装在assets目录中？是否有（批量）工具将源转换为带有9补丁块的编译版本？我真的非常非常喜欢不必使用Eclipse / Ant来构建.apk，然后选择它来提取已编译的9补丁文件（如果可能的话）。

现在我只想从资源目录中读取（例如，每个皮肤有一个子目录）以保持简单。下一步是编译源映像以添加到9补丁块中。之后我会担心即时下载到/ data文件夹 - 如果我无法编译9补丁文件那么添加服务器端的工作就没什么意义了。

Answer 1

没有简单的方法可以做到这一点。 9-patch编译由aapt完成并且相当简单：它丢弃黑色边框并在PNG块内编码其内容。编写一个类似的工具对你来说是相当微不足道的。请注意，您甚至不需要使用相同的格式。如果你看一下doc中的各种NinePatch API，你会看到你可以提交你自己的“块”（它对扩展区域和填充进行编码）。这里解释了一个块byte []数组的结构：

/**
 * This chunk specifies how to split an image into segments for
 * scaling.
 *
 * There are J horizontal and K vertical segments.  These segments divide
 * the image into J*K regions as follows (where J=4 and K=3):
 *
 *      F0   S0    F1     S1
 *   +-----+----+------+-------+
 * S2|  0  |  1 |  2   |   3   |
 *   +-----+----+------+-------+
 *   |     |    |      |       |
 *   |     |    |      |       |
 * F2|  4  |  5 |  6   |   7   |
 *   |     |    |      |       |
 *   |     |    |      |       |
 *   +-----+----+------+-------+
 * S3|  8  |  9 |  10  |   11  |
 *   +-----+----+------+-------+
 *
 * Each horizontal and vertical segment is considered to by either
 * stretchable (marked by the Sx labels) or fixed (marked by the Fy
 * labels), in the horizontal or vertical axis, respectively. In the
 * above example, the first is horizontal segment (F0) is fixed, the
 * next is stretchable and then they continue to alternate. Note that
 * the segment list for each axis can begin or end with a stretchable
 * or fixed segment.
 *
 * The relative sizes of the stretchy segments indicates the relative
 * amount of stretchiness of the regions bordered by the segments.  For
 * example, regions 3, 7 and 11 above will take up more horizontal space
 * than regions 1, 5 and 9 since the horizontal segment associated with
 * the first set of regions is larger than the other set of regions.  The
 * ratios of the amount of horizontal (or vertical) space taken by any
 * two stretchable slices is exactly the ratio of their corresponding
 * segment lengths.
 *
 * xDivs and yDivs point to arrays of horizontal and vertical pixel
 * indices.  The first pair of Divs (in either array) indicate the
 * starting and ending points of the first stretchable segment in that
 * axis. The next pair specifies the next stretchable segment, etc. So
 * in the above example xDiv[0] and xDiv[1] specify the horizontal
 * coordinates for the regions labeled 1, 5 and 9.  xDiv[2] and
 * xDiv[3] specify the coordinates for regions 3, 7 and 11. Note that
 * the leftmost slices always start at x=0 and the rightmost slices
 * always end at the end of the image. So, for example, the regions 0,
 * 4 and 8 (which are fixed along the X axis) start at x value 0 and
 * go to xDiv[0] and slices 2, 6 and 10 start at xDiv[1] and end at
 * xDiv[2].
 *
 * The array pointed to by the colors field lists contains hints for
 * each of the regions.  They are ordered according left-to-right and
 * top-to-bottom as indicated above. For each segment that is a solid
 * color the array entry will contain that color value; otherwise it
 * will contain NO_COLOR.  Segments that are completely transparent
 * will always have the value TRANSPARENT_COLOR.
 *
 * The PNG chunk type is "npTc".
 */
struct Res_png_9patch
{
    Res_png_9patch() : wasDeserialized(false), xDivs(NULL),
                       yDivs(NULL), colors(NULL) { }

    int8_t wasDeserialized;
    int8_t numXDivs;
    int8_t numYDivs;
    int8_t numColors;

    // These tell where the next section of a patch starts.
    // For example, the first patch includes the pixels from
    // 0 to xDivs[0]-1 and the second patch includes the pixels
    // from xDivs[0] to xDivs[1]-1.
    // Note: allocation/free of these pointers is left to the caller.
    int32_t* xDivs;
    int32_t* yDivs;

    int32_t paddingLeft, paddingRight;
    int32_t paddingTop, paddingBottom;

    enum {
        // The 9 patch segment is not a solid color.
        NO_COLOR = 0x00000001,

        // The 9 patch segment is completely transparent.
        TRANSPARENT_COLOR = 0x00000000
    };
    // Note: allocation/free of this pointer is left to the caller.
    uint32_t* colors;

    // Convert data from device representation to PNG file representation.
    void deviceToFile();
    // Convert data from PNG file representation to device representation.
    void fileToDevice();
    // Serialize/Marshall the patch data into a newly malloc-ed block
    void* serialize();
    // Serialize/Marshall the patch data
    void serialize(void* outData);
    // Deserialize/Unmarshall the patch data
    static Res_png_9patch* deserialize(const void* data);
    // Compute the size of the serialized data structure
    size_t serializedSize();
};

Answer 2

这是一种适用于我的解决方法。

我的应用程序中有默认的9色块图像，用作消息气泡。我想创建可下载的themes来更改气泡和字体颜色等其他内容。

可绘制文件夹中包含的*.9.png图像是默认图像，它们在图像周围包括黑色像素：

default_outgoing.9.png

“自定义” /主题气泡的尺寸完全相同，但位置进行了细微更改，仍然使用默认的“块”区域，但是这些区域中不包含黑色像素或.9文件名：

pink_round_outgoing.png

那么自定义商品如何工作并且仍然看起来不错？以下是一些代码，可用来获取自定义图像，从默认的9补丁图像中获取一些值并将其应用于自定义位图：

//Get the custom replacement image
Bitmap bitmap = BitmapFactory.decodeFile(folderpath + File.separator + "pink_round_outgoing.png");

//Get padding from the default 9-patch drawable
Drawable existingDrawable = ContextCompat.getDrawable(this, R.drawable.default_outgoing);
Rect padding = new Rect();
if (existingDrawable != null) {
    existingDrawable.getPadding(padding);
}

//Get 9-patch chunk from the default 9-patch drawable
Bitmap existingBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.default_outgoing);
byte[] chunk = existingBitmap.getNinePatchChunk();

//Finally create your custom 9-Patch drawable and set it to background
NinePatchDrawable d = new NinePatchDrawable(getResources(), bitmap, chunk, padding, null);
view.setBackground(d);

Android：编译要在drawable文件夹之外使用的9补丁文件？

2 个答案: