插件化理解

1.插件化的形式其实有挺多种，之前项目中使用的时apk安装的方法。开发比较简单，也可以做扩展，以及两个apk间共享数据，但用户体验比较差

2.其实应该比较正规的方法应该是classloadder进行动态加载。

下面是使用dexClassLoader进行动态加载的例子（需要注意的一点是：4.1系统上需要做一些特殊处理）

（笔记来源：

http://blog.zhourunsheng.com/2011/09/探秘腾讯android手机游戏平台之不安装游戏apk直接启动法/?utm_source=rss&utm_medium=rss&utm_campaign=%25e6%258e%25a2%25e7%25a7%2598%25e8%2585%25be%25e8%25ae%25afandroid%25e6%2589%258b%25e6%259c%25ba%25e6%25b8%25b8%25e6%2588%258f%25e5%25b9%25b3%25e5%258f%25b0%25e4%25b9%258b%25e4%25b8%258d%25e5%25ae%2589%25e8%25a3%2585%25e6%25b8%25b8%25e6%2588%258fapk%25e7%259b%25b4%25e6%258e%25a5%25e5%2590%25af%25e5%258a%25a8%25e6%25b3%2595

http://blog.csdn.net/yangjunjiezai/article/details/8668265）

//第一个应用，为主程序，进行正常安装，并调起要下载的插件/mnt/sdcard/TestB.apk

public class MainActivity extends Activity {private static final String TAG = "MainActivity";@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);Button btn = (Button) findViewById(R.id.btn);btn.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {Bundle paramBundle = new Bundle();paramBundle.putBoolean("KEY_START_FROM_OTHER_ACTIVITY", true);String dexpath = "/mnt/sdcard/TestB.apk";String dexoutputpath = "dex";LoadAPK(paramBundle, dexpath, dexoutputpath);}});}public void LoadAPK(Bundle paramBundle, String dexpath, String dexoutputpath) {ClassLoader localClassLoader = ClassLoader.getSystemClassLoader();DexClassLoader localDexClassLoader;if(Build.VERSION.SDK_INT == 16){File dexOutputDir = MainActivity.this.getDir(dexoutputpath, 0);localDexClassLoader = new DexClassLoader(dexpath, dexOutputDir.getAbsolutePath(), null, ClassLoader.getSystemClassLoader().getParent());}elselocalDexClassLoader = new DexClassLoader(dexpath,dexoutputpath, null, localClassLoader);try {PackageInfo plocalObject = getPackageManager().getPackageArchiveInfo(dexpath, 1);if ((plocalObject.activities != null)&& (plocalObject.activities.length > 0)) {String activityname = plocalObject.activities[0].name;Log.d(TAG, "activityname = " + activityname);Class localClass = localDexClassLoader.loadClass(activityname);Constructor localConstructor = localClass.getConstructor(new Class[] {});Object instance = localConstructor.newInstance(new Object[] {});Log.d(TAG, "instance = " + instance);Method localMethodSetActivity = localClass.getDeclaredMethod("setActivity", new Class[] { Activity.class });localMethodSetActivity.setAccessible(true);localMethodSetActivity.invoke(instance, new Object[] { this });Method methodonCreate = localClass.getDeclaredMethod("onCreate", new Class[] { Bundle.class });methodonCreate.setAccessible(true);methodonCreate.invoke(instance, new Object[] { paramBundle });}return;} catch (Exception ex) {ex.printStackTrace();}}

第二个应用不安装，直接下载即可，以下是代码：

private static final String TAG = "TestBActivity";private Activity otherActivity; @Overridepublic void onCreate(Bundle savedInstanceState) {boolean b = false;if (savedInstanceState != null) {b = savedInstanceState.getBoolean("KEY_START_FROM_OTHER_ACTIVITY", false);if (b) {this.otherActivity.setContentView(new TBSurfaceView(this.otherActivity));}}if (!b) {super.onCreate(savedInstanceState);// setContentView(R.layout.main);setContentView(new TBSurfaceView(this));}}public void setActivity(Activity paramActivity) {Log.d(TAG, "setActivity..." + paramActivity);this.otherActivity = paramActivity;}

</pre>注意4.1上的特殊处理：<p></p><p></p><p></p><pre code_snippet_id="432800" snippet_file_name="blog_20140722_4_9787005" name="code" class="java">if(Build.VERSION.SDK_INT == 16){File dexOutputDir = MainActivity.this.getDir(dexoutputpath, 0);localDexClassLoader = new DexClassLoader(dexpath, dexOutputDir.getAbsolutePath(), null, ClassLoader.getSystemClassLoader().getParent());}elselocalDexClassLoader = new DexClassLoader(dexpath,dexoutputpath, null, localClassLoader);