android.app.Application上的android classcastexception

概述运行以下应用程序时出现以下异常活动：packagecom.google.android.SmartStudentmCompanion;importjava.io.BufferedReader;importjava.io.IOException;importjava.util.ArrayList;importjava.util.List;importorg.apache.http.HttpResponse;importorg.apache.http

运行以下应用程序时出现以下异常

活动：

package com.Google.androID.SmartStudentmCompanion;import java.io.BufferedReader;import java.io.IOException;import java.util.ArrayList;import java.util.List;import org.apache.http.httpResponse;import org.apache.http.nameValuePair;import org.apache.http.clIEnt.httpClIEnt;import org.apache.http.clIEnt.entity.UrlEncodedFormEntity;import org.apache.http.clIEnt.methods.httpPost;import org.apache.http.message.BasicnameValuePair;import org.apache.http.util.EntityUtils;import androID.app.Activity;import androID.content.Intent;import androID.os.Bundle;import androID.vIEw.VIEw;import androID.Widget.button;import androID.Widget.EditText;import androID.Widget.Toast;public class Login extends  Activity{    public static String ip_address="192.168.1.101";    EditText username;     EditText password;    button login;    button exit;    Toast toast;    /** Called when the activity is first created. */    @OverrIDe    public voID onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentVIEw(R.layout.loginscreen);        System.out.println("onCreate()...");        username = (EditText) findVIEwByID(R.ID.username);        password = (EditText) findVIEwByID(R.ID.password);        this.login = (button)findVIEwByID(R.ID.loginbutton);        this.login.setonClickListener(new VIEw.OnClickListener() {            String usrnm;            String pwd;            @OverrIDe            public voID onClick(VIEw v) {                usrnm = username.getText().toString();                pwd = password.getText().toString();                System.out.println("onClick()...");                int length = 0;                try {                    System.out.println("hello");                    String page = executehttpPost(usrnm,pwd);                    System.out.println(page);                    length = page.length();                } catch (Exception e) {                    // Todo auto-generated catch block                    e.printstacktrace();                }                if (length == 0){                    Toast.makeText(getApplicationContext(),                             "InvalID username and/or password",                             Toast.LENGTH_SHORT).show();                }                else {                    /*Toast.makeText(getApplicationContext(),                             "ValID username and password",                             Toast.LENGTH_SHORT).show();*/                    Intent myIntent = new Intent(v.getContext(), VIDeoVIEwer.class);                    startActivityForResult(myIntent, 0);                }            }        });        this.exit = (button)findVIEwByID(R.ID.exitbutton);        this.exit.setonClickListener(new VIEw.OnClickListener() {            @OverrIDe            public voID onClick(VIEw v) {                finish();            }        });    }    public String executehttpPost(String username, String password) throws Exception {        BufferedReader in = null;        try {            ApplicationEx app = (ApplicationEx)this.getApplication();            httpClIEnt clIEnt = app.gethttpClIEnt();            httpPost request = new httpPost("http://"+ip_address+"/smartstudentmcompanion/check.PHP");            List<nameValuePair> postParameters = new ArrayList<nameValuePair>();            postParameters.add(new BasicnameValuePair("un", username));            postParameters.add(new BasicnameValuePair("pwd", password));            UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(postParameters);            request.setEntity(formEntity);            httpResponse response = clIEnt.execute(request);            /*in = new BufferedReader(new inputStreamReader(response.getEntity().getContent()));            StringBuffer sb = new StringBuffer("");            String line = "";            String NL = System.getProperty("line.separator");            while ((line = in.readline()) != null) {                sb.append(line + NL);            }            in.close();*/            String page = EntityUtils.toString(response.getEntity());            System.out.println("page: " + page);            return page;            } finally {            if (in != null) {                try {                    in.close();                } catch (IOException e) {                    e.printstacktrace();                }            }        }    }}

应用：

package com.Google.androID.SmartStudentmCompanion;import org.apache.http.httpVersion;import org.apache.http.clIEnt.httpClIEnt;import org.apache.http.conn.ClIEntConnectionManager;import org.apache.http.conn.scheme.PlainSocketFactory;import org.apache.http.conn.scheme.Scheme;import org.apache.http.conn.scheme.SchemeRegistry;import org.apache.http.conn.ssl.SSLSocketFactory;import org.apache.http.impl.clIEnt.DefaulthttpClIEnt;import org.apache.http.impl.conn.tsccm.ThreadSafeClIEntConnManager;import org.apache.http.params.BasichttpParams;import org.apache.http.params.httpParams;import org.apache.http.params.httpProtocolParams;import org.apache.http.protocol.http;import androID.app.Application;import androID.util.Log;public class ApplicationEx extends Application {    private static final String TAG = "ApplicationEx";    private httpClIEnt httpClIEnt;    @OverrIDe    public voID onCreate(){        super.onCreate();        httpClIEnt = createhttpClIEnt();    }    @OverrIDe    public voID onLowMemory() {        super.onLowMemory();        shutdownhttpClIEnt();    }    @OverrIDe    public voID onTerminate() {        super.onTerminate();        shutdownhttpClIEnt();    }    private httpClIEnt createhttpClIEnt(){        Log.d(TAG,"createhttpClIEnt()...");        httpParams params = new BasichttpParams();        httpProtocolParams.setVersion(params, httpVersion.http_1_1);        httpProtocolParams.setContentCharset(params, http.DEFAulT_CONTENT_CHARSET);        httpProtocolParams.setUseExpectContinue(params, true);        SchemeRegistry schReg = new SchemeRegistry();        schReg.register(new Scheme("http",                PlainSocketFactory.getSocketFactory(), 80));        schReg.register(new Scheme("https",                SSLSocketFactory.getSocketFactory(), 443));        ClIEntConnectionManager conMgr = new ThreadSafeClIEntConnManager(params,schReg);        return new DefaulthttpClIEnt(conMgr, params);    }    public httpClIEnt gethttpClIEnt() {        return httpClIEnt;    }    private voID shutdownhttpClIEnt() {        if(httpClIEnt!=null && httpClIEnt.getConnectionManager()!=null) {            httpClIEnt.getConnectionManager().shutdown();        }    }}

表现：

    <?xml version="1.0" enCoding="utf-8"?><manifest xmlns:androID="http://schemas.androID.com/apk/res/androID"      package="com.Google.androID.SmartStudentmCompanion"      androID:versionCode="1"      androID:versionname="1.0">    <application androID:icon="@drawable/icon" androID:label="@string/app_name">        <activity androID:name=".Login"                  androID:label="@string/app_name">            <intent-filter>                <action androID:name="androID.intent.action.MAIN" />                <category androID:name="androID.intent.category.LAUNCHER" />            </intent-filter>        </activity>        <activity androID:name=".VIDeoVIEwer"></activity>    </application>     <uses-permission        androID:name="androID.permission.INTERNET" />     <uses-sdk androID:minSdkVersion="8" /></manifest> 

解决方法:

在你的明显改变

<application androID:icon="@drawable/icon" androID:label="@string/app_name">

至

<application androID:icon="@drawable/icon" androID:label="@string/app_name"    androID:name=".ApplicationEx">

由于您尚未声明< applicaton>的androID：name, *** 作系统将查找默认的Application类.为了将其指向您的Application子类,您应该使用androID：name属性.

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