子线程

概述原文链接：http://www.cnblogs.com/guoxinglei/p/3432229.html   子线程通知主线程更新UI  AndroidManifest.xml文件：<manifestxmlns:android="http://schemas.android.com/apkes/android"package="com.example.android_enjoy_ 原文链接：http://www.cnblogs.com/guoxinglei/p/3432229.html

 

 

 

子线程通知主线程更新UI 

 

AndroIDManifest.xml文件：

<manifest xmlns:androID="http://schemas.androID.com/apk/res/androID"    package="com.example.androID_enjoy_thread"    androID:versionCode="1"    androID:versionname="1.0" >    <uses-sdk        androID:minSdkVersion="8"        androID:targetSdkVersion="15" />  <uses-permission androID:name="androID.permission.INTERNET"/>    <application        androID:icon="@drawable/ic_launcher"        androID:label="@string/app_name"        androID:theme="@style/Apptheme" >        <activity            androID:name=".MainActivity"            androID:label="@string/Title_activity_main" >            <intent-filter>                <action androID:name="androID.intent.action.MAIN" />                <category androID:name="androID.intent.category.LAUNCHER" />            </intent-filter>        </activity>    </application></manifest>

VIEw Code

 

 

xml文件：

<linearLayout 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:orIEntation="vertical"    >   <ScrollVIEw        androID:ID="@+ID/scroll"       androID:layout_wIDth="fill_parent"       androID:layout_height="wrap_content"       androID:layout_weight="1"       >               <TextVIEw            androID:ID="@+ID/textvIEw"        androID:layout_wIDth="fill_parent"        androID:layout_height="wrap_content"        androID:hint="@string/hello_world"      />   </ScrollVIEw>        <EditText         androID:layout_marginleft="10dip"        androID:ID="@+ID/edittext"        androID:layout_wIDth="300dip"        androID:layout_height="wrap_content"        androID:hint="请输入网址http://："        />    <button         androID:layout_marginleft="105dip"        androID:ID="@+ID/button"        androID:layout_wIDth="wrap_content"        androID:layout_height="wrap_content"        androID:text="点击我"/></linearLayout>

VIEw Code

java文件：

1.无子线程，无Handler处理器：

 java代码：

import java.io.BufferedReader;import java.io.ByteArrayOutputStream;import java.io.inputStream;import java.io.inputStreamReader;import java.net.httpURLConnection;import java.net.URL;import androID.app.Activity;import androID.os.Bundle;import androID.text.TextUtils;import androID.vIEw.VIEw;import androID.vIEw.VIEw.OnClickListener;import androID.Widget.button;import androID.Widget.EditText;import androID.Widget.TextVIEw;import androID.Widget.Toast;public class MainActivity extends Activity implements OnClickListener {    private button btn;    private EditText et ;    private TextVIEw tv;    @OverrIDe    public voID onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentVIEw(R.layout.activity_main);        btn = (button)findVIEwByID(R.ID.button);        et = (EditText)findVIEwByID(R.ID.edittext);        tv = (TextVIEw)findVIEwByID(R.ID.textvIEw);        btn.setonClickListener(this);    }    @OverrIDe    public voID onClick(VIEw v) {        String path = et.getText().toString();        switch (v.getID()) {        case R.ID.button:            if (TextUtils.isEmpty(path)) {                Toast.makeText(getApplicationContext(), "请输入网址", 1).show();            }            try {                URL url = new URL(path);                httpURLConnection conn = (httpURLConnection) url.openConnection();                 conn.setRequestMethod("GET");                conn.setConnectTimeout(5000);                int code = conn.getResponseCode();                if (code == 200) {                    inputStream input = conn.getinputStream();                    String text = inputStreamTools(input);                    tv.setText(text);                }else{              Toast.makeText(getApplicationContext(), "输入网站不存在", 1).show();                    }            } catch (Exception e) {                e.printstacktrace();            }            break;        }    }        //自定义一个读取输入流的方法    public String inputStreamTools(inputStream input){        //创建BufferedReader对象 读取一行        BufferedReader br = new BufferedReader(new inputStreamReader(input));        //创建ByteArrayOutputStream对象        ByteArrayOutputStream out = new ByteArrayOutputStream();        String line = null ;        try {            //边读边写，将内容写到ByteArrayOutputStream对象out中            while((line = br.readline())!=null){                out.write(line.getBytes());            }        } catch (Exception e) {            e.printstacktrace();        }        //将流转化为String类型，返回String类型        return out.toString();    }}

VIEw Code

2.有子线程，无Handler处理器： java代码：

import java.io.BufferedReader;import java.io.ByteArrayOutputStream;import java.io.inputStream;import java.io.inputStreamReader;import java.net.httpURLConnection;import java.net.URL;import androID.app.Activity;import androID.os.Bundle;import androID.text.TextUtils;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 implements OnClickListener { protected static final int PATH_NulL = 1;protected static final int PATH_EXIST = 2;protected static final int PATH_ERROR = 3;private button btn; private EditText et ; private TextVIEw tv;    @OverrIDe    public voID onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentVIEw(R.layout.activity_main);        btn = (button)findVIEwByID(R.ID.button);        et = (EditText)findVIEwByID(R.ID.edittext);        tv = (TextVIEw)findVIEwByID(R.ID.textvIEw);        btn.setonClickListener(this);    }    @OverrIDe    public voID onClick(VIEw v) {        switch (v.getID()) {        case R.ID.button:            new Thread(new Runnable() {                String path = et.getText().toString();                @OverrIDe                public voID run() {                    if (TextUtils.isEmpty(path)) {                        System.out.println("请输入网址");                    }                    try {                        URL url = new URL(path);                        httpURLConnection conn = (httpURLConnection) url.openConnection();                         conn.setRequestMethod("GET");//设置联网方式为GET方式                        conn.setConnectTimeout(5000);//设置网络连接时间                        int code = conn.getResponseCode();                        if (code == 200) {//如果code的值为200，则表示联网成功，path有效                            inputStream input = conn.getinputStream();                            String text = inputStreamTools(input);                            System.out.println("网站内容："+text);                        }else {                            System.out.println("输入网址错误！");                        }                    } catch (Exception e) {                                            }                                    }            }).start();            break;        }    }        //自定义一个读取输入流的方法    public String inputStreamTools(inputStream input){        //创建BufferedReader对象 读取一行        BufferedReader br = new BufferedReader(new inputStreamReader(input));        //创建ByteArrayOutputStream对象        ByteArrayOutputStream out = new ByteArrayOutputStream();        String line = null ;        try {            //边读边写，将内容写到ByteArrayOutputStream对象out中            while((line = br.readline())!=null){                out.write(line.getBytes());            }        } catch (Exception e) {            e.printstacktrace();        }        //将流转化为String类型，返回String类型        return out.toString();    }}

VIEw Code

 

3.有子线程，有Handler处理器：

java代码：

import java.io.BufferedReader;import java.io.ByteArrayOutputStream;import java.io.inputStream;import java.io.inputStreamReader;import java.net.httpURLConnection;import java.net.URL;import androID.app.Activity;import androID.os.Bundle;import androID.os.Handler;import androID.os.Message;import androID.text.TextUtils;import androID.vIEw.VIEw;import androID.vIEw.VIEw.OnClickListener;import androID.Widget.button;import androID.Widget.EditText;import androID.Widget.TextVIEw;import androID.Widget.Toast;public class MainActivity extends Activity implements OnClickListener { protected static final int PATH_NulL = 1;protected static final int PATH_EXIST = 2;protected static final int PATH_ERROR = 3;private button btn; private EditText et ; private TextVIEw tv; private Handler handler = new Handler(){    /* (non-Javadoc)     * @see androID.os.Handler#handleMessage(androID.os.Message)     */    @OverrIDe    public voID handleMessage(Message msg) {         switch (msg.what) {        case PATH_NulL:            Toast.makeText(getApplicationContext(), "请输入网址", 1).show();            break;        case PATH_EXIST:            String text = (String) msg.obj;            tv.setText(text);            break;        case PATH_ERROR:            Toast.makeText(getApplicationContext(), "输入网站不存在", 1).show();            break;        default:            break;        }        super.handleMessage(msg);    }           };    @OverrIDe    public voID onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentVIEw(R.layout.activity_main);        btn = (button)findVIEwByID(R.ID.button);        et = (EditText)findVIEwByID(R.ID.edittext);        tv = (TextVIEw)findVIEwByID(R.ID.textvIEw);        btn.setonClickListener(this);    }    @OverrIDe    public voID onClick(VIEw v) {        switch (v.getID()) {        case R.ID.button:            new Thread(new Runnable() {                String path = et.getText().toString();                @OverrIDe                public voID run() {                    if (TextUtils.isEmpty(path)) {                        Message msg = Message.obtain();                        msg.what = PATH_NulL;                        handler.sendMessage(msg);                    }                    try {                        URL url = new URL(path);                        httpURLConnection conn = (httpURLConnection) url.openConnection();                         conn.setRequestMethod("GET");//设置联网方式为GET方式                        conn.setConnectTimeout(5000);//设置网络连接时间                        int code = conn.getResponseCode();                        if (code == 200) {//如果code的值为200，则表示联网成功，path有效                            inputStream input = conn.getinputStream();                            String text = inputStreamTools(input);                            Message msg = Message.obtain();                             msg.obj = text;                             msg.what = PATH_EXIST;                            handler.sendMessage(msg);                        }else {                            Message msg = Message.obtain();                            msg.what = PATH_ERROR;                            handler.sendMessage(msg);                        }                    } catch (Exception e) {                                            }                                    }            }).start();            break;        }    }        //自定义一个读取输入流的方法    public String inputStreamTools(inputStream input){        //创建BufferedReader对象 读取一行        BufferedReader br = new BufferedReader(new inputStreamReader(input));        //创建ByteArrayOutputStream对象        ByteArrayOutputStream out = new ByteArrayOutputStream();        String line = null ;        try {            //边读边写，将内容写到ByteArrayOutputStream对象out中            while((line = br.readline())!=null){                out.write(line.getBytes());            }        } catch (Exception e) {            e.printstacktrace();        }        //将流转化为String类型，返回String类型        return out.toString();    }}

VIEw Code

注意：1.AndroIDManifest.xml中要配置访问网络的权限：<uses-permission androID:name="androID.permission.INTERNET"/>

         2.为了避免线程争抢产生的安全隐患，Google工程师在设计AndroID系统的时候，只有主线程才可以修改UI，子线程是不可以直接修改UI的，也不可以直接d出Toast(土司)。

        3.

转载于:https://www.cnblogs.com/guoxinglei/p/3432229.HTML

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