Android App瘦身实战

aapt l -v xxx.apk或unzip -l xxx.apk

/* these formats are already compressed, or don't compress well */
static const char* kNoCompressExt[] = {
    ".jpg", ".jpeg", ".png", ".gif",
    ".wav", ".mp2", ".mp3", ".ogg", ".aac",
    ".mpg", ".mpeg", ".mid", ".midi", ".smf", ".jet",
    ".rtttl", ".imy", ".xmf", ".mp4", ".m4a",
    ".m4v", ".3gp", ".3gpp", ".3g2", ".3gpp2",
    ".amr", ".awb", ".wma", ".wmv", ".webm", ".mkv"
};

appPlugin.variantManager.variantDataList.each { variantData ->
    variantData.outputs.each {
        def sourceApFile = it.packageAndroidArtifactTask.getResourceFile();
        def destApFile = new File("${sourceApFile.name}.temp", sourceApFile.parentFile);
        it.packageAndroidArtifactTask.doFirst {
            byte[] buf = new byte[1024 * 8];

            ZipInputStream zin = new ZipInputStream(new FileInputStream(sourceApFile));
            ZipOutputStream out = new ZipOutputStream(new FileOutputStream(destApFile));

            ZipEntry entry = zin.getNextEntry();
            while (entry != null) {
                String name = entry.getName();

                // Add ZIP entry to output stream.
                ZipEntry zipEntry = new ZipEntry(name);

                if (ZipEntry.STORED == entry.getMethod() && !okayToCompress(entry.getName())) {
                    zipEntry.setMethod(ZipEntry.STORED)
                    zipEntry.setSize(entry.getSize())
                    zipEntry.setCompressedSize(entry.getCompressedSize())
                    zipEntry.setCrc(entry.getCrc())
                } else {
                    zipEntry.setMethod(ZipEntry.DEFLATED)
                    ...
                }
                ...

                out.putNextEntry(zipEntry);
                out.closeEntry();
                entry = zin.getNextEntry();
            }
            // Close the streams
            zin.close();
            out.close();

            sourceApFile.delete();
            destApFile.renameTo(sourceApFile);
        }
    }
}

minifyEnabled true

android {
    buildTypes {
        release {
            minifyEnabled true
            proguardFiles getDefaultProguardFile(‘proguard-android.txt'),
                    'proguard-rules.pro'
        }
    }
    ...
}

boolean isPNGWebpConvertSupported() {
    if (!isWebpConvertEnable()) {
        return false
    }

    // Android 4.0+
    return GradleUtils.getAndroidExtension(project).defaultConfig.minSdkVersion.apiLevel >= 14
    // 4.0
}

boolean isTransparencyPNGWebpConvertSupported() {
    if (!isWebpConvertEnable()) {
        return false
    }

    // Lossless, Transparency, Android 4.2.1+
    return GradleUtils.getAndroidExtension(project).defaultConfig.minSdkVersion.apiLevel >= 18
    // 4.3
}

def convert() {
    String resPath = "${project.buildDir}/${AndroidProject.FD_INTERMEDIATES}/res/merged/${variant.dirName}"
    def resDir = new File("${resPath}")
    resDir.eachDirMatch(~/drawable[a-z0-9-]*/) { dir ->
        FileTree tree = project.fileTree(dir: dir)
        tree.filter { File file ->
            return (isJPGWebpConvertSupported() && (file.name.endsWith(SdkConstants.DOT_JPG) || file.name.endsWith(SdkConstants.DOT_JPEG))) || (isPNGWebpConvertSupported() && file.name.endsWith(SdkConstants.DOT_PNG) && !file.name.endsWith(SdkConstants.DOT_9PNG))
        }.each { File file ->
            def shouldConvert = true
            if (file.name.endsWith(SdkConstants.DOT_PNG)) {
                if (!isTransparencyPNGWebpConvertSupported()) {
                    shouldConvert = !Imaging.getImageInfo(file).isTransparent()
                }
            }
            if (shouldConvert) {
                WebpUtils.encode(project, webpFactorQuality, file.absolutePath, webp)
            }
        }
    }
}

android {
    ...
    buildTypes {
        release {
            shrinkResources true
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android.txt'),
                    'proguard-rules.pro'
        }
    }
}

  // A 1x1 pixel PNG of type BufferedImage.TYPE_BYTE_GRAY
    public static final long TINY_PNG_CRC = 0x88b2a3b0L;

    // A 3x3 pixel PNG of type BufferedImage.TYPE_INT_ARGB with 9-patch markers
    public static final long TINY_9PNG_CRC = 0x1148f987L;

    // The XML document <x/> as binary-packed with AAPT
    public static final long TINY_XML_CRC = 0xd7e65643L;

variantData.outputs.each {
    def apFile = it.packageAndroidArtifactTask.getResourceFile();

    it.packageAndroidArtifactTask.doFirst {
        def arscFile = new File(apFile.parentFile, "resources.arsc");
        JarUtil.extractZipEntry(apFile, "resources.arsc", arscFile);

        def HashMap<String, ArrayList<DuplicatedEntry>> duplicatedResources = findDuplicatedResources(apFile);

        removeZipEntry(apFile, "resources.arsc");

        if (arscFile.exists()) {
            FileInputStream arscStream = null;
            ResourceFile resourceFile = null;
            try {
                arscStream = new FileInputStream(arscFile);

                resourceFile = ResourceFile.fromInputStream(arscStream);
                List<Chunk> chunks = resourceFile.getChunks();

                HashMap<String, String> toBeReplacedResourceMap = new HashMap<String, String>(1024);

                // 处理arsc并删除重复资源
                Iterator<Map.Entry<String, ArrayList<DuplicatedEntry>>> iterator = duplicatedResources.entrySet().iterator();
                while (iterator.hasNext()) {
                    Map.Entry<String, ArrayList<DuplicatedEntry>> duplicatedEntry = iterator.next();

                    // 保留第一个资源，其他资源删除掉
                    for (def index = 1; index < duplicatedEntry.value.size(); ++index) {
                        removeZipEntry(apFile, duplicatedEntry.value.get(index).name);

                        toBeReplacedResourceMap.put(duplicatedEntry.value.get(index).name, duplicatedEntry.value.get(0).name);
                    }
                }

                for (def index = 0; index < chunks.size(); ++index) {
                    Chunk chunk = chunks.get(index);
                    if (chunk instanceof ResourceTableChunk) {
                        ResourceTableChunk resourceTableChunk = (ResourceTableChunk) chunk;
                        StringPoolChunk stringPoolChunk = resourceTableChunk.getStringPool();
                        for (def i = 0; i < stringPoolChunk.stringCount; ++i) {
                            def key = stringPoolChunk.getString(i);
                            if (toBeReplacedResourceMap.containsKey(key)) {
                                stringPoolChunk.setString(i, toBeReplacedResourceMap.get(key));
                            }
                        }
                    }
                }

            } catch (IOException ignore) {
            } catch (FileNotFoundException ignore) {
            } finally {
                if (arscStream != null) {
                    IOUtils.closeQuietly(arscStream);
                }

                arscFile.delete();
                arscFile << resourceFile.toByteArray();

                addZipEntry(apFile, arscFile);
            }
        }
    }
}