需要首先了解一下Activity启动流程源码分析和类的加载流程，上篇文章有介绍到，https://www.jianshu.com/p/d2732de5fef0
思路
整体思路
- 先获取已经运行的 dexElement
- 获取下载好的补丁的 dexElement
- 把补丁的dexElement 插到 已经运行的 dexElement 的最前面 合并
FixDexBug工具类
public class FixDexBug {
private Context mContext;
private File mDexDir;
private String TAG = "FixDexManager";
public FixDexBug(Context context) {
this.mContext = context;
// 获取应用可以访问的dex目录
this.mDexDir = context.getDir("odex", Context.MODE_PRIVATE);
}
/**
* 修复dex包
*
* @param fixDexPath
*/
public void fixDex(String fixDexPath) throws Exception {
// 2. 获取下载好的补丁的 dexElement
// 2.1 移动到系统能够访问的 dex目录下 ClassLoader
File srcFile = new File(fixDexPath);
if (!srcFile.exists()) {
throw new FileNotFoundException(fixDexPath);
}
File destFile = new File(mDexDir, srcFile.getName());
if (destFile.exists()) {
Log.d(TAG, "patch [" + fixDexPath + "] has be loaded.");
return;
}
copyFile(srcFile, destFile);
// 2.2 ClassLoader读取fixDex路径 为什么加入到集合 已启动可能就要修复 BaseApplication
List<File> fixDexFiles = new ArrayList<>();
fixDexFiles.add(destFile);
fixDexFiles(fixDexFiles);
}
/**
* 把dexElements注入到classLoader中
*
* @param classLoader
* @param dexElements
*/
private void injectDexElements(ClassLoader classLoader, Object dexElements) throws Exception {
// 1.先获取 pathList
Field pathListField = BaseDexClassLoader.class.getDeclaredField("pathList");
// IOC 熟悉反射
pathListField.setAccessible(true);
Object pathList = pathListField.get(classLoader);
// 2. pathList里面的dexElements
Field dexElementsField = pathList.getClass().getDeclaredField("dexElements");
dexElementsField.setAccessible(true);
dexElementsField.set(pathList, dexElements);
}
/**
* 合并两个数组
*
* @param arrayLhs
* @param arrayRhs
* @return
*/
private static Object combineArray(Object arrayLhs, Object arrayRhs) {
Class<?> localClass = arrayLhs.getClass().getComponentType();
int i = Array.getLength(arrayLhs);
int j = i + Array.getLength(arrayRhs);
Object result = Array.newInstance(localClass, j);
for (int k = 0; k < j; ++k) {
if (k < i) {
Array.set(result, k, Array.get(arrayLhs, k));
} else {
Array.set(result, k, Array.get(arrayRhs, k - i));
}
}
return result;
}
/**
* copy file
*
* @param src source file
* @param dest target file
* @throws IOException
*/
public static void copyFile(File src, File dest) throws IOException {
FileChannel inChannel = null;
FileChannel outChannel = null;
try {
if (!dest.exists()) {
dest.createNewFile();
}
inChannel = new FileInputStream(src).getChannel();
outChannel = new FileOutputStream(dest).getChannel();
inChannel.transferTo(0, inChannel.size(), outChannel);
} finally {
if (inChannel != null) {
inChannel.close();
}
if (outChannel != null) {
outChannel.close();
}
}
}
/**
* 从classLoader中获取 dexElements
*
* @param classLoader
* @return
*/
private Object getDexElementsByClassLoader(ClassLoader classLoader) throws Exception {
// 1.先获取 pathList
Field pathListField = BaseDexClassLoader.class.getDeclaredField("pathList");
// IOC 熟悉反射
pathListField.setAccessible(true);
Object pathList = pathListField.get(classLoader);
// 2. pathList里面的dexElements
Field dexElementsField = pathList.getClass().getDeclaredField("dexElements");
dexElementsField.setAccessible(true);
return dexElementsField.get(pathList);
}
/**
* 加载全部的修复包
*/
public void loadFixDex() throws Exception {
File[] dexFiles = mDexDir.listFiles();
List<File> fixDexFiles = new ArrayList<>();
for (File dexFile : dexFiles) {
if (dexFile.getName().endsWith(".dex")) {
fixDexFiles.add(dexFile);
}
}
fixDexFiles(fixDexFiles);
}
/**
* 修复dex
*
* @param fixDexFiles
*/
private void fixDexFiles(List<File> fixDexFiles) throws Exception {
// 1. 先获取已经运行的 dexElement
ClassLoader applicationClassLoader = mContext.getClassLoader();
Object applicationDexElements = getDexElementsByClassLoader(applicationClassLoader);
File optimizedDirectory = new File(mDexDir, "odex");
if (!optimizedDirectory.exists()) {
optimizedDirectory.mkdirs();
}
// 修复
for (File fixDexFile : fixDexFiles) {
// dexPath dex路径
// optimizedDirectory 解压路径
// libraryPath .so文件位置
// parent 父ClassLoader
ClassLoader fixDexClassLoader = new BaseDexClassLoader(
fixDexFile.getAbsolutePath(),// dex路径 必须要在应用目录下的odex文件中
optimizedDirectory,// 解压路径
null,// .so文件位置
applicationClassLoader // 父ClassLoader
);
Object fixDexElements = getDexElementsByClassLoader(fixDexClassLoader);
// 3. 把补丁的dexElement 插到 已经运行的 dexElement 的最前面 合并
// applicationClassLoader 数组 合并 fixDexElements 数组
// 3.1 合并完成
applicationDexElements = combineArray(fixDexElements, applicationDexElements);
}
// 3.2 把合并的数组注入到原来的类中 applicationClassLoader
injectDexElements(applicationClassLoader, applicationDexElements);
}
}
使用
BaseApplication
try {
FixDexBug fixDexBug=new FixDexBug(this);
fixDexBug.loadFixDex();
} catch (Exception e) {
e.printStackTrace();
}
MainActivity
public class MainActivity extends BaseSkinActivity {
@Override
protected void initData() {
fixDexBug();
}
@Override
protected void initView() {
Button button= (Button) findViewById(R.id.test_tv);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
startActivity(TestActivity.class);
}
});
}
/**
* 修复bug
*/
private void fixDexBug() {
File fixFile = new File("/sdcard/Download/", "fix.dex");
Log.e("TAG",fixFile.exists()+"");
if (fixFile.exists()) {
FixDexBug fixDexBug = new FixDexBug(this);
try {
fixDexBug.fixDex(fixFile.getAbsolutePath());
Toast.makeText(this, "修复成功", Toast.LENGTH_SHORT).show();
} catch (Exception e) {
e.printStackTrace();
Toast.makeText(this,"修复失败",Toast.LENGTH_LONG).show();
}
}
}
@Override
protected void initTitle() {
}
@Override
protected void setContentView() {
setContentView(R.layout.activity_main);
}
}
TestActivity
public class TestActivity extends BaseSkinActivity implements View.OnClickListener {
@Override
protected void initData() {
}
@Override
protected void initView() {
// 初始化View
Button button= (Button) findViewById(R.id.test_tv);
button.setOnClickListener(this);
}
@Override
protected void initTitle() {
// 初始化头部
}
@Override
protected void setContentView() {
setContentView(R.layout.activity_main);
}
@Override
public void onClick(View v) {
Toast.makeText(this, 2/0+ "测试", Toast.LENGTH_LONG).show();
// Activity 启动流程
}
}
最后将正确的apk，重命名为fix.zip,然后解压选择fix.dex,拷贝即可
