Android获取应用程序的大小 博客分类： Android AndroidOSF#Security

package chroya.demo;

import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.util.concurrent.CountDownLatch;

import android.app.Activity;
import android.content.Context;
import android.content.pm.PackageStats;
import android.content.pm.PackageManager.NameNotFoundException;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;

public class Main extends Activity {
	private PackageStats ps;
	
	public void getPackageStats(String packageName) {
		try {
			//获取setting包的的Context
			Context mmsCtx = createPackageContext("com.android.settings",
			        Context.CONTEXT_INCLUDE_CODE | Context.CONTEXT_IGNORE_SECURITY);
			//使用setting的classloader加载com.android.settings.ManageApplications类
			Class<?> maClass = Class.forName("com.android.settings.ManageApplications", true, mmsCtx.getClassLoader());
			//创建它的一个对象
			Object maObject = maClass.newInstance();
			
			/*
			 * 将私有域mPm赋值。因为mPm在SizeObserver的invokeGetSize中用到了，
			 * 却因为没有执行onCreate而没有初始化，所以要在此处初始化。
			 */
			Field f_mPm = maClass.getDeclaredField("mPm");
			f_mPm.setAccessible(true);            
			f_mPm.set(maObject, mmsCtx.getPackageManager());
            
			/*
			 * 给mHandler赋值为重新定义的Handler，以便接收SizeObserver的
			 * onGetStatsCompleted回调方法中dispatch的消息，从中取PackageStats对象。
			 * */
            Field f_mHandler = maClass.getDeclaredField("mHandler");
            f_mHandler.setAccessible(true);
            f_mHandler.set(maObject, new Handler() {
            	  public void handleMessage(Message msg) {
            		  if(msg.what == 1) {
            			  //此处获取到PackageStats对象
            			  ps = (PackageStats) msg.getData().getParcelable("ApplicationPackageStats");            			  
            			  Log.d("", ""+ps.codeSize);            			  
            		  }
            	  }
            });
            
			//加载内部类SizeObserver
			Class<?> sizeObserverClass = Class.forName("com.android.settings.ManageApplications$SizeObserver", true, mmsCtx.getClassLoader());
			Constructor sizeObserverConstructor = sizeObserverClass.getDeclaredConstructors()[0];
			sizeObserverConstructor.setAccessible(true);
			/*
			 * 创建SizeObserver对象，两个参数，第一个是外部类的对象，
			 * 也就是ManageApplications对象，第二个是msgId，也就是
			 * 分发消息的id，跟Handler接收的msgId一样。
			 * */
    		Object soObject = sizeObserverConstructor.newInstance(maObject, 1);
    		//执行invokeGetSize方法
    		sizeObserverClass.getMethod("invokeGetSize", String.class,
    				CountDownLatch.class).invoke(soObject, packageName, new CountDownLatch(1));    		
		} catch (NameNotFoundException e) {
			e.printStackTrace();
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		} catch (IllegalAccessException e) {
			e.printStackTrace();
		} catch (IllegalArgumentException e) {
			e.printStackTrace();
		} catch (SecurityException e) {
			e.printStackTrace();
		} catch (InvocationTargetException e) {
			e.printStackTrace();
		} catch (NoSuchMethodException e) {
			e.printStackTrace();
		} catch (InstantiationException e) {
			e.printStackTrace();
		} catch (NoSuchFieldException e) {
			e.printStackTrace();
		}
	}
	
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);  
        getPackageStats("chroya.demo");       
    }
}