手机安全卫士的学习（1）

今天学习的主要是SplashActivity页面的初始化，其中涉及很多知识点

1 获取包名 获取版本号信息

2 检查升级，以及利用第三方工具对json数据的解析

3 Thread线程和message的运用

package com.djf.mobilesafty;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

import org.json.JSONException;
import org.json.JSONObject;

import com.djf.mobilesafty.utils.StreamTools;

import android.app.Activity;
import android.content.Intent;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.text.Annotation;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.animation.AlphaAnimation;
import android.widget.TextView;
import android.widget.Toast;

public class SplashActivity extends Activity {
    protected static final String TAG = "SplashActivity";
    protected static final int ENTER_HOME = 0;
    protected static final int SHOW_DIALOG = 1;
    protected static final int URL_ERROR = 2;
    protected static final int NET_ERROR = 3;
    protected static final int JSON_ERROR = 4;
    private TextView tv_splash_verison;
    private String description;
    private String apkurl;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv_splash_verison = (TextView) findViewById(R.id.tv_splash_verison);
        tv_splash_verison.setText("版本号：" + getVersionName());
        AlphaAnimation aa = new AlphaAnimation(0.2f, 1.0f);
        aa.setDuration(500);
        findViewById(R.layout.activity_main).startAnimation(aa);

        // 检查升级
        checkupdate();
    }

    private Handler handler = new Handler() {
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            switch (msg.what) {
            case ENTER_HOME:// 进入主页面
                EnterHome();
                break;
            case SHOW_DIALOG:// 显示对话框
                Log.i(TAG, "显示升级对话框");
                break;
            case URL_ERROR:// url错误
                EnterHome();
                Toast.makeText(getApplicationContext(), "url错误", 0).show();
                break;
            case NET_ERROR:// 网络错误
                EnterHome();
                Toast.makeText(SplashActivity.this, "网络错误", 0).show();
                break;
            case JSON_ERROR:// json解析出错
                EnterHome();
                Toast.makeText(SplashActivity.this, "json解析出错", 0).show();
                break;
            default:
                break;
            }
        }

    };

    protected void EnterHome() {
        // TODO Auto-generated method stub
        Intent intent = new Intent(this, HomeActivity.class);
        startActivity(intent);
        // 关闭当前页面
        finish();
    };

    /**
     * 检查是否需要升级
     */
    private void checkupdate() {
        // http://125.39.51.195:8080/updatinfo.html
        new Thread() {
            public void run() {
                Message msg = Message.obtain();
                long starttime = System.currentTimeMillis();
                try {

                    URL url = new URL(getString(R.string.serverurl));
                    HttpURLConnection connection = (HttpURLConnection) url
                            .openConnection();
                    connection.setRequestMethod("GET");
                    connection.setReadTimeout(4000);
                    int code = connection.getResponseCode();
                    if (code == 200) {
                        InputStream in = connection.getInputStream();
                        // 把流转化成string
                        String result = StreamTools.readFromStream(in);
                        Log.i(TAG, "联网成功" + result);
                        // json解析
                        JSONObject obj = new JSONObject(result);
                        // 得到服务器的版本信息
                        String version = (String) obj.get("version");
                        description = (String) obj.get("description");
                        apkurl = (String) obj.get("apkurl");
                        // 校验是否有新版本
                        if (getVersionName().equals(version)) {
                            // 版本一致
                            msg.what = ENTER_HOME;
                        } else {
                            // 版本不一致
                            msg.what = SHOW_DIALOG;
                        }
                    }
                } catch (MalformedURLException e) {
                    msg.what = URL_ERROR;
                    e.printStackTrace();
                } catch (IOException e) {
                    msg.what = NET_ERROR;
                    e.printStackTrace();

                } catch (JSONException e) {
                    // TODO Auto-generated catch block
                    msg.what = JSON_ERROR;
                    e.printStackTrace();
                } finally {
                    long endtime = System.currentTimeMillis();
                    long dtime = endtime - starttime;
                    if (dtime < 2000) {
                        try {
                            Thread.sleep(2000 - dtime);
                        } catch (InterruptedException e) {
                            // TODO Auto-generated catch block
                            e.printStackTrace();
                        }
                    }
                    handler.sendMessage(msg);
                }

            };
        }.start();
    }

    /**
     * 得到应用程序信息的版本
     */
    private String getVersionName() {
        PackageManager pManager = getPackageManager();
        try {
            PackageInfo info = pManager.getPackageInfo(getPackageName(), 0);
            return info.versionName;
        } catch (NameNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return "";
    }
}