Android 动态加载APK--代码安装、获取安装包中的资源及Intent调用已安装apk

文章出处：http://blog.csdn.net/zhang957411207/article/details/7581070

最近在研究Android动态加载APK技术，偶有小得，共享一下，欢迎交流。

首先是Android 动态加载已安装的APK

被调用工程TestB：

其工程已添加了字符串、颜色和图片资源，这里不写了，读者可自行添加。

public class TestBActivity extends Activity{/** Called when the activity is first created. */@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);Button button=(Button)findViewById(R.id.button1);button.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubToast.makeText(TestBActivity.this, "this is testB", Toast.LENGTH_SHORT).show();}});}}

接着把TestB打包为TestB.apk，放到sdcard的根目录。

调用工程TestA：

首先应该是安装apk文件：

protected void InstallAPK(String apkname) {// TODO Auto-generated method stub//代码安装String fileName = Environment.getExternalStorageDirectory() + "/"+apkname; Intent intent = new Intent(Intent.ACTION_VIEW); intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);// intent.setDataAndType(Uri.parse("file://"+fileName), "application/vnd.android.package-archive");  intent.setDataAndType(Uri.fromFile(new File(fileName)), "application/vnd.android.package-archive"); TestAActivity.this.startActivityForResult(intent, 1);

但是安装之前是不是要先检测一下TestB.apk是否已安装呢：

protected boolean checkInstall(String pak) {// TODO Auto-generated method stubboolean install=false;PackageManager pm=getPackageManager();try {PackageInfo info=pm.getPackageInfo(pak,1);if (info!=null&&info.activities.length>0) {install=true;}} catch (NameNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();}return install;}

如果未安装，便调用InstallAPK（String apkname）安装，如果已安装便可代码获取其资源：

private void getRes(String pak){if (checkInstall(pak)) {try {Context ctxTestB = getTestContext(pak);Resources res = ctxTestB.getResources();// 获取字符串stringString hello = res.getString(getId("string", "hello", pak));((TextView) findViewById(R.id.testb_string)).setText(hello);// 获取图片DrawableDrawable drawable = res.getDrawable(getId("drawable", "testb",pak));((ImageView) findViewById(R.id.testb_drawable)).setImageDrawable(drawable);// 获取颜色值int color = res.getColor(getId("color", "white",pak));((TextView) findViewById(R.id.testb_color)).setBackgroundColor(color);// 获取布局文件View view = getView(ctxTestB, getId("layout", "main",pak));LinearLayout layout = (LinearLayout) findViewById(R.id.testb_layout);layout.addView(view);} catch (NameNotFoundException e) {e.printStackTrace();}}} //获取资源对应的编号private int getId(String name, String type,String pak) {return testb.getIdentifier(name, type, pak);} // 获取视图public View getView(Context ctx, int id) {return ((LayoutInflater) ctx.getSystemService(Context.LAYOUT_INFLATER_SERVICE)).inflate(id,null);} //获取TestB的Contextprivate Context getTestContext(String pak) throws NameNotFoundException {return createPackageContext(pak,Context.CONTEXT_IGNORE_SECURITY | Context.CONTEXT_INCLUDE_CODE);}

接下来再来看看怎么使用Intent组件启动被调用工程：

protected void startAPK(String pak) {// TODO Auto-generated method stub//代码启动try {                       //pak=PACKAGE_TEST_B+".TestBActivity"ContextctxTestB = getTestContext(PACKAGE_TEST_B);Class cls = ctxTestB.getClassLoader().loadClass(pak);TestAActivity.this.startActivity(new Intent(ctxTestB, cls));} catch (ClassNotFoundException e) {e.printStackTrace();} catch (NameNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();}}

以下为扩展内容：

比如加上网络下载apk文件功能，然后再安装，这里使用的是URL通信协议，用HttpURLConnection类，面向的是应用层：

protected File downLoadFile(String httpUrl) {                // TODO Auto-generated method stubString filename="down_TestB.apk";File file=new File(Environment.getExternalStorageDirectory() + "/"+filename);                try {                        URL url = new URL(httpUrl);                        try {                                HttpURLConnection conn = (HttpURLConnection) url                                                .openConnection();                                InputStream is = conn.getInputStream();                                FileOutputStream fos = new FileOutputStream(file);                                byte[] buf = new byte[256];                                conn.connect();                                int count = 0;                                if (conn.getResponseCode()==200) {                                       while ((count=is.read(buf))>0) {                                       fos.write(buf, 0, count);}                                }                                conn.disconnect();                                fos.close();                                is.close();                        } catch (IOException e) {                                // TODO Auto-generated catch block                                e.printStackTrace();                        }                } catch (MalformedURLException e) {                        // TODO Auto-generated catch block                        e.printStackTrace();                }                return file;        }

此工程还可扩展，比如获取未安装apk或者已安装apk的版本、图标等资源，和已安装的apk进行版本比较，以确定是否要升级新版本。关于此可以看下我的另一篇博文《Android获取未安装和已安装apk的版本、图标等资源》。

Ok，到此结束！

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