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Android开发学习笔记-实现联网检测程序版本

 

package com.frank.mobilesafe;import java.io.InputStream;import java.net.HttpURLConnection;import java.net.MalformedURLException;import java.net.URI;import java.net.URL;import javax.net.ssl.HttpsURLConnection;import org.apache.http.HttpClientConnection;import org.apache.http.client.methods.HttpUriRequest;import org.json.JSONObject;import com.frank.mobilesafe.utils.FileHelper;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.util.Log;import android.view.Window;import android.widget.TextView;import android.widget.Toast;public class SplashActivity extends Activity {    private static final int SHOW_UPDATE_DIALOG = 0;    protected static final int REQUEST_FAILURE = 1;    protected static final int REQUEST_ERROR = 2;    private static final int SHOW_HOME = 3;    private Handler handler = new Handler() {        @Override        public void handleMessage(Message msg) {            HandlerStartMessage(msg.what);        }    };    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        // requestWindowFeature(Window.FEATURE_NO_TITLE);设置无标题        setContentView(R.layout.activity_splash);        TextView tv_version = (TextView) findViewById(R.id.tv_version);        tv_version.setText(getVersion());        CheckUpdate();    }    protected void HandlerStartMessage(int what) {        switch (what) {        case SHOW_UPDATE_DIALOG:            Toast.makeText(this, "该升级了", 0).show();            break;        case SHOW_HOME:            //Toast.makeText(this, "show home activity", 0).show();            ShowMainActivity();            break;        case REQUEST_FAILURE:            Toast.makeText(this, "REQUEST_FAILURE", 0).show();            break;        default:            break;        }    }/** * 显示主界面 */    private void ShowMainActivity() {        // TODO Auto-generated method stub        Intent intent = new Intent(this,MainActivity.class);        startActivity(intent);        finish();            }    /**     * 检查升级     */    protected void CheckUpdate() {        new Thread() {            public void run() {                long startTime = System.currentTimeMillis();                Message msg = Message.obtain();                try {                    URL url = new URL("http://192.168.1.104/1.html");// 网络链接地址                    HttpURLConnection conn = (HttpURLConnection) url                            .openConnection();// 创建连接对象                    conn.setRequestMethod("GET");// 设置请求方式                    conn.setReadTimeout(5000);// 设置请求超时时间                                        if (200 == conn.getResponseCode())// 当请成功的时候执行                    {                        InputStream inputStream = conn.getInputStream();                        FileHelper helper = new FileHelper();                        String content = helper.StreamToString(inputStream);                        Log.i("a", content);                        JSONObject obj = new JSONObject(content);                        String version = (String) obj.get("version");                        Log.i("version", version);                        if (version == getVersion()) {                            msg.what = SHOW_UPDATE_DIALOG;                        }                        else                        {                            msg.what = SHOW_HOME;                        }                    } else {                        Log.i("a", "请求失败!");                        msg.what = REQUEST_FAILURE;                    }                } catch (Exception e) {                    Log.i("a", "shibai");                    msg.what = REQUEST_ERROR;                    e.printStackTrace();                } finally {                    long endTime = System.currentTimeMillis();                    long spanTime = endTime-startTime;                    if (spanTime<2000) {                        try {                            Thread.sleep(2000-spanTime);                        } catch (InterruptedException e) {                            // TODO Auto-generated catch block                            e.printStackTrace();                        }                    }                    handler.sendMessage(msg);                }            };        }.start();    }    /**     * 获取版本信息     *      * @return     */    protected String getVersion() {        String versionStr = "";        PackageManager packManger = getPackageManager();        try {            PackageInfo info = packManger.getPackageInfo(getPackageName(), 0);            versionStr = info.versionName;// 获取的版本信息        } catch (NameNotFoundException e) {            // TODO Auto-generated catch block            versionStr = "";            e.printStackTrace();        }        return versionStr;    }}

问题总结:

1、在解析JSON的时候需要情况一直遇到异常,出错异常信息为org.json.JSONException: Value ? of type java.lang.String cannot be converted to JSONObject,经查得是在保存json文本的时候是使用的记事本造成的,这也就是说在保存JSON的使用应该使用editplus等文本编辑器进行保存,保存的格式应该为utf8 无bom格式,这样在进行解析的时候就不会造成异常。

2、在联网获取数据的时候,因为是在本机iis上配置的站点,不过在请求数据的时候一直请求不到,遇到的第一个原因就是没有对请求设置请求方式以及请求时间,之后对百度等其他网站进行请求都没问题,却对自己配置的请求不了,经过抓耳挠腮之后,查的原因竟是http后面的反斜线少了一个。大意了!

3、在线程内访问线程外的资源的时候,需要使用java事件机制进行处理。主要方法如下:

    private Handler handler = new Handler() {        @Override        public void handleMessage(Message msg) {            HandlerStartMessage(msg.what);        }    };
protected void CheckUpdate() {        new Thread() {            public void run() {                long startTime = System.currentTimeMillis();                Message msg = Message.obtain();              msg.what = SHOW_UPDATE_DIALOG;              handler.sendMessage(msg);                }            };        }.start();

 

Android开发学习笔记-实现联网检测程序版本