Android动态加载jar，dex，apk文件

image.png

坑

1.程序没给分配sd卡权限

2. mContext.getClassLoader()

public interface ITest {
    public void getWebUrl(String webUrl,OnGetDownLoadUrlListener listener);
}
public interface OnGetDownLoadUrlListener {
    void onSuccess(String downUrl);
    void onFailed(String error);
}

package com.example.apk;

import android.annotation.SuppressLint;
import android.content.Context;

import java.io.File;
import java.lang.reflect.Constructor;

import dalvik.system.DexClassLoader;

/**
 * @author：LiJiaZhi on 2018/4/13
 * @des：ToDo
 * @org mtime.com
 */
public class Test implements ITest {

    private ITest mTest;
    private Context mContext;
    private String mJarPath;
    private String mClassName;

    public Test(Context context) {
        mContext = context;
        getTestInstanceDynamicFromSDCard();
    }

    /**
     * 一定要注意必须有sd卡权限，不然一直报错，class not found
     */
    @SuppressLint("NewApi")
    private void getTestInstanceDynamicFromSDCard() {
        // get test instance by dynamic
        mJarPath = android.os.Environment.getExternalStorageDirectory().getAbsolutePath() + "/Download/loader.dex";// 前半部分为获得SD卡的目录
        mClassName = "com.example.apk.out.DemoTest";//和导出之前的包名和类名保持一致
        File dexOutputDir = mContext.getApplicationContext().getDir("dex", 0);//
        File file = new File(mJarPath);
        DexClassLoader classLoader = new DexClassLoader(file.getAbsolutePath(),
                dexOutputDir.getAbsolutePath(), null, mContext.getClassLoader());
        try {
            Class<?> clazz = classLoader.loadClass(mClassName);
            Constructor<?> constructor = clazz.getConstructor(new Class[]{});//得到构造器
            mTest = (ITest) constructor.newInstance();//实例化

//or这种方法
//Class clazz = classLoader.loadClass(mClassName);
//mTest = (ITest) clazz.newInstance();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    @Override
    public void getWebUrl(String webUrl, OnGetDownLoadUrlListener listener) {
        mTest.getWebUrl(webUrl,listener);
    }
}