因為當前項目功能越來越多,編譯速度越來越慢(公司電腦配置也挺差的...),並且方法數已超出65535的限制了,雖然通過multidex暫時解決了,但是這並不是一個好的解決方式。所以通過插件來加快編譯速度以及解決方法數的限制,算是一個越來越重要的任務了,工作中還有很多新需求,所以趁放假的2天研究了下現在比較流行的插件框架dynamic-load-apk,並整理了下。
框架github地址:https://github.com/singwhatiwanna/dynamic-load-apk
lib module的svn地址:https://github.com/singwhatiwanna/dynamic-load-apk/trunk/DynamicLoadApk/lib
一、加載apk總流程:
//插件文件 File plugin = new File(apkPath); PluginItem item = new PluginItem(); //插件文件路徑 item.pluginPath = plugin.getAbsolutePath(); //PackageInfo = PackageManager.getPackageArchiveInfo item.packageInfo = DLUtils.getPackageInfo(this, item.pluginPath); //launcherActivity if (item.packageInfo.activities != null && item.packageInfo.activities.length > 0) { item.launcherActivityName = item.packageInfo.activities[0].name; } //launcherService if (item.packageInfo.services != null && item.packageInfo.services.length > 0) { item.launcherServiceName = item.packageInfo.services[0].name; } //加載apk信息 DLPluginManager.getInstance(this).loadApk(item.pluginPath);
二、loadApk信息過程:
1、createDexClassLoader:
private DexClassLoader createDexClassLoader(String dexPath) { dexOutputPath = mContext.getDir("dex", Context.MODE_PRIVATE).getAbsolutePath(); DexClassLoader loader = new DexClassLoader(dexPath, dexOutputPath, //getDir("dex", Context.MODE_PRIVATE) mNativeLibDir, //optimizedDirectory=getDir("pluginlib", Context.MODE_PRIVATE) mContext.getClassLoader()); //host.Appliceation.getClassLoader() return loader; }
2、createAssetManager:
private AssetManager createAssetManager(String dexPath) { try { AssetManager assetManager = AssetManager.class.newInstance(); //通過反射調用addAssetPath方法,將apk資源加載到AssetManager Method addAssetPath = assetManager.getClass().getMethod("addAssetPath", String.class); addAssetPath.invoke(assetManager, dexPath); return assetManager; } catch (Exception e) { e.printStackTrace(); return null; } }
后面會重寫DLProxyActivity的getAssets()方法,返回此處生成的AssetManager,從而實現從插件apk加載資源:
@Override public AssetManager getAssets() { return impl.getAssets() == null ? super.getAssets() : impl.getAssets(); }
3、createResources:
private Resources createResources(AssetManager assetManager) { //通過剛創建的assetManager以及宿主程序的Resources創建Plugin的Resources Resources superRes = mContext.getResources(); Resources resources = new Resources(assetManager, superRes.getDisplayMetrics(), superRes.getConfiguration()); return resources; }
后面會重寫DLProxyActivity的getResources()方法,返回此處生成的Resources,從而實現從插件apk加載資源:
@Override public Resources getResources() { return impl.getResources() == null ? super.getResources() : impl.getResources(); }
4、創建pluginPackage並通過插件的packageName保存插件信息:
pluginPackage = new DLPluginPackage(dexClassLoader, resources, packageInfo);
mPackagesHolder.put(packageInfo.packageName, pluginPackage);
5、copySoLib(拷貝so文件到應用的pluginlib目錄下):
SoLibManager.getSoLoader().copyPluginSoLib(mContext, dexPath, mNativeLibDir);
三、調用插件:
1、要向插件Intent傳遞可序列化對象,必須通過DLIntent,設置Bundle的ClassLoader:
@Override public Intent putExtra(String name, Parcelable value) { setupExtraClassLoader(value); return super.putExtra(name, value); } @Override public Intent putExtra(String name, Serializable value) { setupExtraClassLoader(value); return super.putExtra(name, value); } private void setupExtraClassLoader(Object value) { ClassLoader pluginLoader = value.getClass().getClassLoader(); DLConfigs.sPluginClassloader = pluginLoader; setExtrasClassLoader(pluginLoader); //設置Bundle的ClassLoader }
2、startPluginActivity:
插件內部的activity之間相互調用,需要使用此方法。
public int startPluginActivityForResult(Context context, DLIntent dlIntent, int requestCode) { if (mFrom == DLConstants.FROM_INTERNAL) { dlIntent.setClassName(context, dlIntent.getPluginClass()); performStartActivityForResult(context, dlIntent, requestCode); return DLPluginManager.START_RESULT_SUCCESS; } String packageName = dlIntent.getPluginPackage(); //驗證intent的包名 if (TextUtils.isEmpty(packageName)) { throw new NullPointerException("disallow null packageName."); } //檢測插件是否加載 DLPluginPackage pluginPackage = mPackagesHolder.get(packageName); if (pluginPackage == null) { return START_RESULT_NO_PKG; } //要調用的插件Activity的class完整路徑 final String className = getPluginActivityFullPath(dlIntent, pluginPackage); //Class.forName Class<?> clazz = loadPluginClass(pluginPackage.classLoader, className); if (clazz == null) { return START_RESULT_NO_CLASS; } //獲取代理Activity的class,DLProxyActivity/DLProxyFragmentActivity Class<? extends Activity> proxyActivityClass = getProxyActivityClass(clazz); if (proxyActivityClass == null) { return START_RESULT_TYPE_ERROR; } //put extra data dlIntent.putExtra(DLConstants.EXTRA_CLASS, className); dlIntent.putExtra(DLConstants.EXTRA_PACKAGE, packageName); dlIntent.setClass(mContext, proxyActivityClass); //通過context啟動宿主Activity performStartActivityForResult(context, dlIntent, requestCode); return START_RESULT_SUCCESS; }
四、Activity生命周期的管理:
插件apk中的activity其實就是一個普通的對象,不是真正意義上的activity(沒有在宿主程序中注冊且沒有完全初始化),不具有activity的性質,因為系統啟動activity是要做很多初始化工作的,而我們在應用層通過反射去啟動activity是很難完成系統所做的初始化工作的,所以activity的大部分特性都無法使用包括activity的生命周期管理,這就需要我們自己去管理。
DL采用了接口機制,將activity的大部分生命周期方法提取出來作為一個接口(DLPlugin),然后通過代理activity(DLProxyActivity)去調用插件activity實現的生命周期方法,這樣就完成了插件activity的生命周期管理,並且沒有采用反射,當我們想增加一個新的生命周期方法的時候,只需要在接口中聲明一下同時在代理activity中實現一下即可。
public interface DLPlugin { public void onCreate(Bundle savedInstanceState); public void onStart(); public void onRestart(); public void onActivityResult(int requestCode, int resultCode, Intent data); public void onResume(); public void onPause(); public void onStop(); public void onDestroy(); public void attach(Activity proxyActivity, DLPluginPackage pluginPackage); public void onSaveInstanceState(Bundle outState); public void onNewIntent(Intent intent); public void onRestoreInstanceState(Bundle savedInstanceState); public boolean onTouchEvent(MotionEvent event); public boolean onKeyUp(int keyCode, KeyEvent event); public void onWindowAttributesChanged(LayoutParams params); public void onWindowFocusChanged(boolean hasFocus); public void onBackPressed(); public boolean onCreateOptionsMenu(Menu menu); public boolean onOptionsItemSelected(MenuItem item); }
DLBasePluginActivity的部分實現:
public class DLBasePluginActivity extends Activity implements DLPlugin { /** * 代理activity,可以當作Context來使用,會根據需要來決定是否指向this */ protected Activity mProxyActivity; /** * 等同於mProxyActivity,可以當作Context來使用,會根據需要來決定是否指向this<br/> * 替代this來使用(應為this指向的是插件中的Activity,已經不是常規意義上的activity,所以this是沒有意義的) * 如果是DLPlugin中已經覆蓋的Activity的方法,就不需使用that了,直接調用this即可 */ protected Activity that; protected DLPluginManager mPluginManager; protected DLPluginPackage mPluginPackage; protected int mFrom = DLConstants.FROM_INTERNAL; @Override public void attach(Activity proxyActivity, DLPluginPackage pluginPackage) { mProxyActivity = (Activity) proxyActivity; that = mProxyActivity; mPluginPackage = pluginPackage; } @Override public void onCreate(Bundle savedInstanceState) { if (savedInstanceState != null) { mFrom = savedInstanceState.getInt(DLConstants.FROM, DLConstants.FROM_INTERNAL); } if (mFrom == DLConstants.FROM_INTERNAL) { super.onCreate(savedInstanceState); mProxyActivity = this; that = mProxyActivity; } mPluginManager = DLPluginManager.getInstance(that); } @Override public void setContentView(View view) { if (mFrom == DLConstants.FROM_INTERNAL) { super.setContentView(view); } else { mProxyActivity.setContentView(view); } } ...... }
在代理類DLProxyActivity中的實現:
public class DLProxyActivity extends Activity implements DLAttachable { protected DLPlugin mRemoteActivity; private DLProxyImpl impl = new DLProxyImpl(this); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); impl.onCreate(getIntent()); } @Override public void attach(DLPlugin remoteActivity, DLPluginManager pluginManager) { mRemoteActivity = remoteActivity; } @Override public AssetManager getAssets() { return impl.getAssets() == null ? super.getAssets() : impl.getAssets(); } @Override public Resources getResources() { return impl.getResources() == null ? super.getResources() : impl.getResources(); } @Override public Theme getTheme() { return impl.getTheme() == null ? super.getTheme() : impl.getTheme(); } @Override public ClassLoader getClassLoader() { return impl.getClassLoader(); } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { mRemoteActivity.onActivityResult(requestCode, resultCode, data); super.onActivityResult(requestCode, resultCode, data); } @Override protected void onStart() { mRemoteActivity.onStart(); super.onStart(); } ...... }
總結:
插件主要的2個問題就是資源加載以及Activity生命周期的管理。
資源加載:
通過反射調用AssetManager的addAssetPath方法,我們可以將一個插件apk中的資源加載到AssetManager中,然后再通過AssetManager來創建一個新的Resources對象,然后就可以通過這個Resources對象來訪問插件apk中的資源了。
Activity生命周期管理:
采用接口機制,將activity的大部分生命周期方法提取出來作為一個接口(DLPlugin),然后通過代理activity(DLProxyActivity)去調用插件activity實現的生命周期方法,這樣就完成了插件activity的生命周期管理。
另外,一個需要注意的地方:
插件項目引用 android-support-v4.jar、lib.jar等libs,生成apk時不能將這些打包到apk,只在編譯時引用,只有host項目里才編譯並打包,保證host以及插件中的代碼只有一份。
在studio里面使用provided而非compile:
dependencies {
provided files('provide-jars/android-support-v4.jar')
provided files('provide-jars/lib.jar')
}