Java、Android中的回调（callBack）我写的一个网络回调大家可以参考参考

1首先建立一个activity：

Mainactivity.java文件

package com.example.httpclicentcallback;import android.app.Activity;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.util.Log;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.EditText;import android.widget.TextView;public class MainActivity extends Activity {private TextView textView1;private Button button1;private EditText editText1;private EditText editText2;private static String result="";@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);initView();}private Handler handler=new Handler(){public void handleMessage(android.os.Message msg) {switch (msg.what) {case 0:textView1.setText(result);break;default:break;}};};public void initView(){textView1=(TextView) findViewById(R.id.textView1);button1=(Button) findViewById(R.id.button1);editText1=(EditText) findViewById(R.id.editText1);editText2=(EditText) findViewById(R.id.editText2);button1.setOnClickListener(new OnClickListener() {public void onClick(View arg0) {final String url="你的服务器ip"+"username="+editText1.getText().toString()+"&password="+editText2.getText().toString();new Thread(new Runnable() {@Overridepublic void run() {new HttpClicentTest().compute(url, new HttpCallBackTest() {@Overridepublic void onSuccess(String result) {Log.e("TAG", result);MainActivity.result=result;Message msg=new Message();msg.what=0;handler.sendMessage(msg);//textView1.setText(result);本来我是在这里更新ui的没想到直接报ui线程更新异常，没事咱们用handle更新ui就是了}});}}).start(); }}); }}

xml文件：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    tools:context=".MainActivity" >    <EditText        android:id="@+id/editText1"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_alignParentLeft="true"        android:layout_alignParentTop="true"        android:layout_marginTop="14dp"         >        <requestFocus />    </EditText>    <EditText        android:id="@+id/editText2"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_alignLeft="@+id/editText1"        android:layout_below="@+id/editText1"        android:layout_marginTop="39dp"        />    <Button        android:id="@+id/button1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignLeft="@+id/editText2"        android:layout_below="@+id/editText2"        android:layout_marginTop="45dp"        android:text="Button" />    <TextView        android:id="@+id/textView1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignLeft="@+id/button1"        android:layout_below="@+id/button1"        android:layout_marginTop="78dp"        android:text="TextView" /></RelativeLayout>

2 、定义一个接口：

public interface HttpCallBackTest {public void onSuccess(String result);}

3、建立回调机制

package com.example.httpclicentcallback;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.net.HttpURLConnection;import java.net.URL;import android.os.AsyncTask;public class HttpClicentTest {public void compute(String url,HttpCallBackTest callback){callback.onSuccess(getHttpContext(url));}public String getHttpContext(String ul){String restlt="";URL url=null;HttpURLConnection connection=null;InputStreamReader in=null;try{url = new URL(ul);connection=(HttpURLConnection) url.openConnection();in=new InputStreamReader(connection.getInputStream());BufferedReader bufferedReader=new BufferedReader(in);StringBuffer strBuffer=new StringBuffer();String line=null;while((line=bufferedReader.readLine())!=null){strBuffer.append(line);}restlt=strBuffer.toString();}catch (Exception e){e.printStackTrace();}finally{if(connection!=null){connection.disconnect();}if(in!=null){try {in.close();} catch (IOException e) {e.printStackTrace();}}}return restlt;}class MyAnsyTask extends AsyncTask<String, Void, String>{@Overrideprotected String doInBackground(String... arg0) {return null;}@Overrideprotected void onPostExecute(String result) {super.onPostExecute(result);}@Overrideprotected void onProgressUpdate(Void... values) {super.onProgressUpdate(values);}@Overrideprotected void onPreExecute() {super.onPreExecute();} }}