在非anctivity类中使用Toast

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最近在做android的项目，在子线程中访问网络资源，当网络访问出现异常时想用Toast提示用户。看了一下makeText方法的参数，第一个就是Context，好的，写个局部变量，提供setter()、getter()方法，把主线程的Context传过来，执行，报错了：

04-09 21:14:44.412 7398-7544/com.explame.cuttese.circle3 E/AndroidRuntime﹕ FATAL EXCEPTION: Thread-2376 Process: com.explame.cuttese.circle3, PID: 7398 java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare() at android.os.Handler.<init>(Handler.java:200) at android.os.Handler.<init>(Handler.java:114) at android.widget.Toast$TN.<init>(Toast.java:345) at android.widget.Toast.<init>(Toast.java:100) at android.widget.Toast.makeText(Toast.java:257) at com.explame.cuttese.circle3.service.HttpClientService.run(HttpClientService.java:85)
告诉我缺少Looper.prepare() ，好的加上就是了，别忘了把Looper.loop()也加上，结果OK，Toast就能正常显示了。
终点代码：

Looper.prepare();            Toast.makeText(context,"网络连接出现异常，请检查网络连接后重试。",Toast.LENGTH_LONG).show();            Looper.loop();

全部代码如下：
RegisterActivity.class

package com.explame.cuttese.circle3;import android.app.Activity;import android.app.ProgressDialog;import android.content.Intent;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.util.Log;import android.view.Menu;import android.view.MenuItem;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;import com.explame.cuttese.circle3.service.HttpClientService;import com.explame.cuttese.circle3.service.MD5;import org.json.JSONObject;public class RegisterActivity extends Activity {    private Button register;    private EditText registerUserNameEdit;    private EditText registerUserPasswordEdit;    private EditText registerUserPhoneEdit;    private ProgressDialog progressDialog;    private String userName;    private String userPassword;    private String userPhoene;    private Handler handler;    private static final int REGISTER_SIGN = 0x0001;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_register);        registerUserNameEdit = (EditText)findViewById(R.id.register_user_name);        registerUserPasswordEdit = (EditText)findViewById(R.id.register_user_password);        registerUserPhoneEdit = (EditText)findViewById(R.id.register_user_phone);        register = (Button)findViewById(R.id.register_button);        Intent myIntent = getIntent();        userName = myIntent.getStringExtra("userName");        userPassword = myIntent.getStringExtra("userPassword");        if(null!=userName&&!"".equals(userName)){            registerUserNameEdit.setText(userName.trim());        }        if(null!=userPassword&&!"".equals(userPassword)){            registerUserPasswordEdit.setText(userPassword.trim());        }        myHandler();        register.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v){                userName = registerUserNameEdit.getText().toString().trim();                userPassword = registerUserPasswordEdit.getText().toString().trim();                userPhoene = registerUserPhoneEdit.getText().toString().trim();                if("".equals(userName)){                    Toast.makeText(RegisterActivity.this,"请填写用户名。",Toast.LENGTH_SHORT).show();                }else if("".equals(userPassword)){                    Toast.makeText(RegisterActivity.this,"请填写密码。",Toast.LENGTH_SHORT).show();                }else if("".equals(userPhoene)){                    Toast.makeText(RegisterActivity.this,"请填写手机号。",Toast.LENGTH_SHORT).show();                }else{                    progressDialog = ProgressDialog.show(RegisterActivity.this,"","加载中，请稍等……");                    //密码加密                    try{                        userPassword = new MD5().EncryptByMD5(userPassword);                    }catch (Exception e){                        Toast.makeText(RegisterActivity.this,"请重试。",Toast.LENGTH_SHORT).show();                        return;                    }                    //发起网络请求                    HttpClientService hcs = new HttpClientService();                    hcs.setProgressDialog(progressDialog);                    hcs.setContext(RegisterActivity.this);                    hcs.setHandler(handler);                    hcs.setSign(REGISTER_SIGN);                    hcs.setUrl(getResources().getString(R.string.url) + "userService/userRegister/" + userName + "," + userPassword + "," + userPhoene + ",100.100.100.100,80");                    hcs.start();                    hcs.interrupt();                }            }        });    }    @Override    public boolean onCreateOptionsMenu(Menu menu) {        // Inflate the menu; this adds items to the action bar if it is present.        getMenuInflater().inflate(R.menu.menu_register, menu);        return true;    }    @Override    public boolean onOptionsItemSelected(MenuItem item) {        // Handle action bar item clicks here. The action bar will        // automatically handle clicks on the Home/Up button, so long        // as you specify a parent activity in AndroidManifest.xml.        int id = item.getItemId();        //noinspection SimplifiableIfStatement        if (id == R.id.action_settings) {            return true;        }        return super.onOptionsItemSelected(item);    }    public void myHandler() {        handler = new Handler(){            @Override            public void handleMessage(Message msg) {                progressDialog.dismiss();   //关闭ProgressDialog                if(msg.what==REGISTER_SIGN){                    try {                        String result = msg.obj.toString();                        JSONObject jo = new JSONObject(result);                        String state = jo.get("state").toString().trim();                        if("true".equals(state)){                            Toast.makeText(RegisterActivity.this,"登陆ID为："+jo.getString("loginId"),Toast.LENGTH_SHORT).show();                        }else{                            Toast.makeText(RegisterActivity.this,"网络异常，请检查网络设置后重试",Toast.LENGTH_SHORT).show();                        }                    }catch (Exception e){                    }                }            }        };    }}

HttpClientService.class

package com.explame.cuttese.circle3.service;import android.app.ProgressDialog;import android.content.Context;import android.content.Intent;import android.os.Handler;import android.os.Looper;import android.os.Message;import android.util.Log;import android.widget.Toast;import org.apache.http.HttpResponse;import org.apache.http.HttpStatus;import org.apache.http.client.HttpClient;import org.apache.http.client.methods.HttpGet;import org.apache.http.impl.client.DefaultHttpClient;import org.apache.http.util.EntityUtils;/** * Created by lenovo on 2015/4/30. */public class HttpClientService extends Thread{    private String url = "";    private Handler handler = null;    private int sign = 0;    private ProgressDialog progressDialog;    private Context context;    public String getUrl() {        return url;    }    public void setUrl(String url) {        this.url = url;    }    private Handler getHandler() {        return handler;    }    public void setHandler(Handler handler) {        this.handler = handler;    }    private int getSign() {        return sign;    }    public void setSign(int sign) {        this.sign = sign;    }    public void setProgressDialog(ProgressDialog progressDialog){        this.progressDialog = progressDialog;    }    private ProgressDialog getProgressDialog() {        return progressDialog;    }    public void setContext(Context context) {        this.context = context;    }    private Context getContext() {        return context;    }    @Override    public void run() {        String result = "";        HttpClient httpClient = new DefaultHttpClient();        HttpGet request = new HttpGet(getUrl().replace(" ","%20"));        HttpResponse response = null;        try {            response = httpClient.execute(request);            if(response.getStatusLine().getStatusCode()== HttpStatus.SC_OK){                result = EntityUtils.toString(response.getEntity());            }        }catch(Exception e){            e.printStackTrace();            progressDialog.dismiss();            Looper.prepare();            Toast.makeText(context,"网络连接出现异常，请检查网络连接后重试。",Toast.LENGTH_LONG).show();            Looper.loop();        }        Message message = getHandler().obtainMessage();        message.obj = result;        message.what = sign;        Log.v("msg.obj",result);        getHandler().sendMessage(message);    }}

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