转 android 动态加载 插件模型开发

目前市面上的应用商店，不管是 apple 还是 android 平台， 一般只有一家商店。
如果要动态添加商店，允许多家商店共存。
搭建一个平台，多家应用商店可以加入。
类似于商场与专卖店的关系。
每个商店的业务由各自实现，但统一由商场来提供接口供用户选择。
下面就来简单做个原型：
1 ClassLoadTestMain  商场
2 ClassLoadTestPlugin 商店

3 PluginInterface 商场提供给商店的接口

接口定义：

package com.pathfindeng.android.test;

public interface  IPlugin {

    public int add(int a, int b);

}

package com.pathfindeng.android.test; public interface IPlugin { public int add(int a, int b); }
商店实现接口：

package com.pathfindeng.android.test.plugin;

import com.pathfindeng.android.test.IPlugin;

public class Plugin implements IPlugin{

    public int add(int a, int b){
        return a + b;
    }
}

package com.pathfindeng.android.test.plugin; import com.pathfindeng.android.test.IPlugin; public class Plugin implements IPlugin{ public int add(int a, int b){ return a + b; } }
商场调用商店的实现：

package com.pathfindeng.android.test.main;

import com.pathfindeng.android.test.IPlugin;
import com.pathfindeng.android.test.main.R;

import dalvik.system.DexClassLoader;
import dalvik.system.VMStack;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
import android.widget.Toast;

public class ClassLoadTestMainActivity extends Activity {


    TextView result;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        result = (TextView)findViewById(R.id.result);

    }

    public void doInPlugin(){

        String dexPath, dexOutputDir, libPath ,className;
        ClassLoader parent;

        dexPath = "/data/app/com.pathfindeng.android.test.plugin-1.apk";
        dexOutputDir = "/data/data/com.pathfindeng.android.test.main";

        libPath = "/data/data/com.pathfindeng.android.test.main/lib";

        parent = ClassLoadTestMainActivity.this.getClassLoader();

        //parent = VMStack.getCallingClassLoader();

        DexClassLoader mDexClassLoader = new DexClassLoader(dexPath, dexOutputDir, libPath, parent);

        className = "com.pathfindeng.android.test.plugin.Plugin";

        try {
            Class mClass = mDexClassLoader.loadClass(className);

            IPlugin mIPlugin = (IPlugin)mClass.newInstance();

            int c;
            c = mIPlugin.add(100, 200);

            result.setText("from plugin : "+c);

            Toast.makeText(ClassLoadTestMainActivity.this, "from plugin : "+c, Toast.LENGTH_LONG);


        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (InstantiationException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }


    }

    /* (non-Javadoc)
     * @see android.app.Activity#onResume()
     */
    @Override
    protected void onResume() {
        // TODO Auto-generated method stub
        super.onResume();

        doInPlugin();
    }

    /* (non-Javadoc)
     * @see android.app.Activity#onDestroy()
     */
    @Override
    protected void onDestroy() {
        // TODO Auto-generated method stub
        super.onDestroy();
    }

}

package com.pathfindeng.android.test.main; import com.pathfindeng.android.test.IPlugin; import com.pathfindeng.android.test.main.R; import dalvik.system.DexClassLoader; import dalvik.system.VMStack; import android.app.Activity; import android.os.Bundle; import android.widget.TextView; import android.widget.Toast; public class ClassLoadTestMainActivity extends Activity { TextView result; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); result = (TextView)findViewById(R.id.result); } public void doInPlugin(){ String dexPath, dexOutputDir, libPath ,className; ClassLoader parent; dexPath = "/data/app/com.pathfindeng.android.test.plugin-1.apk"; dexOutputDir = "/data/data/com.pathfindeng.android.test.main"; libPath = "/data/data/com.pathfindeng.android.test.main/lib"; parent = ClassLoadTestMainActivity.this.getClassLoader(); //parent = VMStack.getCallingClassLoader(); DexClassLoader mDexClassLoader = new DexClassLoader(dexPath, dexOutputDir, libPath, parent); className = "com.pathfindeng.android.test.plugin.Plugin"; try { Class mClass = mDexClassLoader.loadClass(className); IPlugin mIPlugin = (IPlugin)mClass.newInstance(); int c; c = mIPlugin.add(100, 200); result.setText("from plugin : "+c); Toast.makeText(ClassLoadTestMainActivity.this, "from plugin : "+c, Toast.LENGTH_LONG); } catch (ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IllegalAccessException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (InstantiationException e) { // TODO Auto-generated catch block e.printStackTrace(); } } /* (non-Javadoc) * @see android.app.Activity#onResume() */ @Override protected void onResume() { // TODO Auto-generated method stub super.onResume(); doInPlugin(); } /* (non-Javadoc) * @see android.app.Activity#onDestroy() */ @Override protected void onDestroy() { // TODO Auto-generated method stub super.onDestroy(); } }

从上面的代码看，调用插件还是强制定义的，不够人性

接下来做些改进。

插件端 注册 固定 Action Name  

<activity android:name=".商店Activity" android:label="@string/app_name">
            <intent-filter>
                <action android:name="接口指定固定 Action Name" />
            </intent-filter>
</activity>

<activity android:name=".商店Activity" android:label="@string/app_name"> <intent-filter> <action android:name="接口指定固定 Action Name" /> </intent-filter> </activity>

服务器端 商场

利用 PackageManager 查询所有注册了接口定义的 Action Name 的商店，并获得信息。

Intent intent = new Intent(Constants.ACTION_PLUGIN, null);
PackageManager pm = mContext.getPackageManager();
List<ResolveInfo> plugins = pm.queryIntentActivities(intent, 0);

Intent intent = new Intent(Constants.ACTION_PLUGIN, null); PackageManager pm = mContext.getPackageManager(); List<ResolveInfo> plugins = pm.queryIntentActivities(intent, 0);
这样之前提到的 

DexClassLoader(dexPath, dexOutputDir, libPath, parent)

DexClassLoader(dexPath, dexOutputDir, libPath, parent)

参数就不需要 手动指定了。

待叙……