Android 动态加载APK--代码安装、获取资源及Intent调用已安装apk

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

截图：

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. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		Button button=(Button)findViewById(R.id.button1);
		button.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				Toast.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 stub
		boolean 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 block
			e.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string
				String hello = res.getString(getId("string", "hello", pak));
				((TextView) findViewById(R.id.testb_string)).setText(hello);
				
				// 获取图片Drawable
				Drawable 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Context
	private 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"
			Context	ctxTestB = 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 block
			e.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 stub
		String 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，本人QQ：957411207，欢迎交流。