扣丁学堂笔记第18天HttpURLConnection与HttpClient

1.概述与http协议介绍

















2.检查网络连接状态





创建一个布尔类型的isNetworkConnected方法，如果context不为空，通过getSystemService得到一个ConnectivityManager的实例cm，再调用cm的getActiveNetworkInfo方法返回一个NetworkInfo的实例info，再判断如果info不为空，返回info的isAvailable方法。

然后在onClick方法判断isNetworkConnected的布尔值，若为true，toast网络可用，否则网络不可用。

最后在清单文件声明网络权限





判断wifi网络与mobile网络是否可用和上文大同小异，只不过是把info的getActiveInfo方法改为getNetworkInfo方法，并且传入ConnectivityManager的TYPE_WIFI或者TYPE_MOBILE标记

MainActivity

package com.example.networkstatetest;

import android.app.Activity;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}

public void checkNetworkClick(View view){
boolean result = isNetworkConnected(this);
boolean result2 = isWifiNetworkConnected(this);
if(result){
Toast.makeText(this, "网络可用", Toast.LENGTH_SHORT).show();
}else{
Toast.makeText(this, "网络不可用", Toast.LENGTH_SHORT).show();
}
if(result2){
Toast.makeText(this, "wifi可用", Toast.LENGTH_SHORT).show();
}else{
Toast.makeText(this, "wifi不可用", Toast.LENGTH_SHORT).show();
}
}

public boolean isNetworkConnected(Context context){
if(context!=null){
ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo info = cm.getActiveNetworkInfo();
if(info!=null){
return info.isAvailable();
}
}
return false;

}

public boolean isWifiNetworkConnected(Context context){
if(context!=null){
ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo wifiInfo = cm.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
if(wifiInfo!=null){
return wifiInfo.isAvailable();
}
}
return false;

}
}

activity_main

<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="com.example.networkstatetest.MainActivity" >

<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:text="检查网络状态"
android:onClick="checkNetworkClick" />

</RelativeLayout>

AndroidMainfest

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>

3.URL与显示网络图片









MainActivity

package com.example.shownetworkimagetest;

import java.io.IOException;
import java.io.InputStream;
import java.lang.ref.WeakReference;
import java.net.MalformedURLException;
import java.net.URL;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.widget.ImageView;

public class MainActivity extends Activity {

private static final int LOAD_SUCCESS = 0x1;
private ImageView iv;
private MyHandler handler = new MyHandler(this);
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
iv = (ImageView) findViewById(R.id.imageView1);
}

private static class MyHandler extends Handler{
private final WeakReference<MainActivity> weakReference;
public MyHandler(MainActivity activity){
weakReference = new WeakReference<MainActivity>(activity);
}
@Override
public void handleMessage(Message msg) {
// TODO Auto-generated method stub
super.handleMessage(msg);
MainActivity activity = weakReference.get();
if(activity!=null){
switch(msg.what){
case LOAD_SUCCESS:
activity.iv.setImageBitmap((Bitmap) msg.obj);
break;
}
}
}
}

public void showClick(View view){
new Thread(new Runnable() {

@Override
public void run() {
// TODO Auto-generated method stub
String path = "http://cdn.duitang.com/uploads/item/201603/09/20160309133128_yz4JP.jpeg";
try {
URL url = new URL(path);
InputStream in = url.openStream();
Bitmap bitmap = BitmapFactory.decodeStream(in);

Message message = handler.obtainMessage(LOAD_SUCCESS, bitmap);
handler.sendMessage(message);

} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}).start();
}
}

activity_main

<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="com.example.shownetworkimagetest.MainActivity" >

<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:text="显示网络图片"
android:onClick="showClick" />

<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_alignRight="@+id/button1"
android:layout_below="@+id/button1"
/>

</RelativeLayout>

AndroidMainfest

<uses-permission android:name="android.permission.INTERNET"/>

4.模拟登陆示例









5.ApacheHttpClient_简介与get请求





6.ApacheHttpClient_post请求