17-07-31 android 方法 如何引用链接获取json数据(改进版）

07-29写的方法今回头一看太烂了，今天对代码进行了改进，当然还需要后续进一步的完善。

MainActivity 的方法部分改进了

package com.example.juren;

import java.io.InputStream;
import java.net.HttpURLConnection;
import java.util.HashMap;
import java.util.Map;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import com.example.juren.MyThread.ResponseInfo;
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.util.Log;

/*
{
"categorys": [
{
"id": "1",
"name": "综合",
"icon": "http://114.55.116.95:8080/shusheng/images/zhonghe.png",
"short_desc": "十八般武器样样精通",
"desc": "NULL"
},
{
"id": "2",
"name": "地理",
"icon": "http://114.55.116.95:8080/shusheng/images/dili.png",
"short_desc": "坐地日行八万里,巡天遥看一千河",
"desc": "NULL"
},
{
"id": "3",
"name": "文学",
"icon": "http://114.55.116.95:8080/shusheng/images/wenxue.png",
"short_desc": "NULL",
"desc": "NULL"
},
{
"id": "4",
"name": "体育",
"icon": "http://114.55.116.95:8080/shusheng/images/tiyu.png",
"short_desc": "NULL",
"desc": "NULL"
},
{
"id": "5",
"name": "生活",
"icon": "http://114.55.116.95:8080/shusheng/images/shenghuo.png",
"short_desc": "NULL",
"desc": "NULL"
},
{
"id": "6",
"name": "生物",
"icon": "http://114.55.116.95:8080/shusheng/images/shengwu.png",
"short_desc": "NULL",
"desc": "NULL"
},
{
"id": "7",
"name": "军事",
"icon": "http://114.55.116.95:8080/shusheng/images/junshi.png",
"short_desc": "NULL",
"desc": "NULL"
},
{
"id": "8",
"name": "历史",
"icon": "http://114.55.116.95:8080/shusheng/images/lishi.png",
"short_desc": "NULL",
"desc": "NULL"
}
],
"status": "success"
}
*/

public class MainActivity extends Activity
{
public static final String URL = "http://114.55.116.95:8080/shusheng/home_page";
private Handler mHandler = new MyHandler();
public LinearItemView mItem1;
public LinearItemView mItem2;
public GridItemView tItem1;
public GridItemView tItem2;
public GridItemView tItem3;
public GridItemView tItem4;
public GridItemView tItem5;
public GridItemView tItem6;

private Map<String, Bitmap> mCache = new HashMap<String, Bitmap>();

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

mItem1 = (LinearItemView) findViewById(R.id.include1);
mItem2 = (LinearItemView) findViewById(R.id.include2);

tItem1 = (GridItemView) findViewById(R.id.include_1);
tItem2 = (GridItemView) findViewById(R.id.include_2);
tItem3 = (GridItemView) findViewById(R.id.include_3);
tItem4 = (GridItemView) findViewById(R.id.include_4);
tItem5 = (GridItemView) findViewById(R.id.include_5);
tItem6 = (GridItemView) findViewById(R.id.include_6);

MyThread thread = new MyThread(URL, mHandler);
thread.start();
}

public class MyHandler extends Handler
{
public void handleMessage(Message msg)
{
if (msg.what == 1)
{
ResponseInfo response = (ResponseInfo) msg.obj;
if (response.status.equals(MyThread.STATUS_FAILED))
{
setfailedUIDatas(response);
}
else
{
HomePageInfo homePageInfo = parseHomePageInfo(response);
setSuccessUIDatas(homePageInfo);

// TODO 下载相关图片
loadImages(homePageInfo);
}
}
else if (msg.what == 1000)
{
Bitmap bmp = mCache.get(msg.obj);
if(msg.arg1 == 1)
{
mItem1.setIcons(bmp);
}
if(msg.arg1 == 2)
{
mItem2.setIcons(bmp);
}
if(msg.arg1 == 3)
{
tItem1.setIcons(bmp);
}
if(msg.arg1 == 4)
{
tItem2.setIcons(bmp);
}
if(msg.arg1 == 5)
{
tItem3.setIcons(bmp);
}
if(msg.arg1 == 6)
{
tItem4.setIcons(bmp);
}
if(msg.arg1 == 7)
{
tItem5.setIcons(bmp);
}
if(msg.arg1 == 8)
{
tItem6.setIcons(bmp);
}
}
}
}

public void setfailedUIDatas(ResponseInfo response)
{

}

public void loadImages(final HomePageInfo homePageInfo)
{
new Thread()
{
public void run()
{
//匿名内部类方法中，想要使用方法参数，需要把参数声明为final类型
for(int i = 0; i < homePageInfo.categorys.size(); i ++)
{
CategoryInfo item = homePageInfo.categorys.get(i);
String url = item.icon;
Bitmap bm1 = getHttpBitmap(url);
mCache.put(url,bm1);

Message msg = new Message();
msg.obj = url;//在HandlMessage中用于找到对应的Bitmap
msg.what = 1000;
msg.arg1 = i+1;//在HandlMessage中找到对应的 ImageView
mHandler.sendMessage(msg);
}
}
}.start();
}

public void setSuccessUIDatas(HomePageInfo homePageInfo)
{
// TODO Auto-generated method stub
Log.i("aaa", "size = " + homePageInfo.categorys.size());
for (int i = 0; i < homePageInfo.categorys.size(); i++)
{
CategoryInfo catInfo = homePageInfo.categorys.get(i);
if (i == 0)
{
mItem1.setDatas(catInfo.name, catInfo.short_desc, catInfo.desc);
}
if (i == 1)
{
mItem2.setDatas(catInfo.name, catInfo.short_desc, catInfo.desc);
}
if (i == 2)
{
tItem1.setDatas(catInfo.name);
}
if (i == 3)
{
tItem2.setDatas(catInfo.name);
}
if (i == 4)
{
tItem3.setDatas(catInfo.name);
}
if (i == 5)
{
tItem4.setDatas(catInfo.name);
}
if (i == 6)
{
tItem5.setDatas(catInfo.name);
}
if (i == 7)
{
tItem6.setDatas(catInfo.name);
}
}
}

public HomePageInfo parseHomePageInfo(ResponseInfo response)
{

HomePageInfo homePageInfo = new HomePageInfo();
// TODO Auto-generated method stub
JSONObject root = null;

try
{
root = new JSONObject(response.responseString);
}
catch (JSONException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}

JSONArray categorysJSONArray = root.optJSONArray("categorys");
for (int i = 0; i < categorysJSONArray.length(); i++)
{
CategoryInfo catInfo = new CategoryInfo();

JSONObject item = (JSONObject) categorysJSONArray.opt(i);
catInfo.id = item.optString("id");
catInfo.name = item.optString("name");
catInfo.icon = item.optString("icon");
catInfo.short_desc = item.optString("short_desc");
catInfo.desc = item.optString("desc");

homePageInfo.categorys.add(catInfo);
}
return homePageInfo;
}

public static Bitmap getHttpBitmap(String url)
{
java.net.URL myFileURL;
Bitmap bitmap = null;
try
{
myFileURL = new java.net.URL(url);
// 获得连接
HttpURLConnection conn = (HttpURLConnection) myFileURL.openConnection();
// 设置超时时间为6000毫秒，conn.setConnectionTiem(0);表示没有时间限制
conn.setConnectTimeout(6000);
// 连接设置获得数据流
conn.setDoInput(true);
// 不使用缓存
conn.setUseCaches(false);
// 这句可有可无，没有影响
// conn.connect();
// 得到数据流
InputStream is = conn.getInputStream();
// 解析得到图片
bitmap = BitmapFactory.decodeStream(is);
// 关闭数据流
is.close();
}
catch (Exception e)
{
e.printStackTrace();
}
return bitmap;
}
}

MyThread.java

package com.example.juren;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;

import org.json.JSONObject;

import android.os.Handler;
import android.os.Message;

public class MyThread extends Thread
{
public Handler mHandler;
public String requrl;
public static final String STATUS_SUCCESS = "success";
public static final String STATUS_FAILED = "failed";

public MyThread(String url, Handler handler)
{
this.requrl = url;
mHandler = handler;
}

public void run()
{
ResponseInfo dat
4000
a = request(requrl);
Message msg = new Message();
msg.what = 1;
msg.obj = data;
mHandler.sendMessage(msg);
}

private ResponseInfo request(String requrl)
{
ResponseInfo responseData = new ResponseInfo();

URLConnection conn;
URL url = null;
HttpURLConnection httpConn = null;
int response = -1;

try
{
InputStream is = null;
url = new URL(requrl);
conn = url.openConnection();// 打开一个链接
conn.setConnectTimeout(10000);// 设置链接超时时间
conn.setReadTimeout(10000);// 设置读取超时时间
httpConn = (HttpURLConnection) conn;
httpConn.setAllowUserInteraction(false);
httpConn.setInstanceFollowRedirects(true);
httpConn.setRequestMethod("GET");// 使用http的Get方法
httpConn.connect();// 开始连接

response = httpConn.getResponseCode();// 每次连接都会有一个response code

if (response == HttpURLConnection.HTTP_OK)
{

// 通过这次连接获取数据
is = httpConn.getInputStream();
String jsonString = convertStreamToString(is);
responseData.responseString = jsonString;
JSONObject object = new JSONObject(jsonString);// 如何使用一个字符串创建一个JSONObject对象
responseData.status = object.optString("status");// 根据一个JSONObject对象中的key来找到value

if (responseData.status.equals(STATUS_SUCCESS))
{
return responseData;
}
// 连接成功了，但服务器返回了无效的数据

responseData.status = STATUS_FAILED;
responseData.exceptionString = "获取数据失败";
return responseData;
}

else
{
responseData.status = STATUS_FAILED;
responseData.exceptionString = "获取数据失败";
return responseData;
}
}
catch (Exception e)
{
responseData.status = STATUS_FAILED;
responseData.exceptionString = "获取数据失败！";
}

finally
{
if (httpConn != null)
{
httpConn.disconnect();
}
}
return responseData;
}

// 把输入流数据转换成字符串数据
public static String convertStreamToString(InputStream is)
{
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line = null;

try
{
while ((line = reader.readLine()) != null)
{
sb.append(line + "\n");
}
}
catch (IOException e)
{
e.printStackTrace();
}
finally
{
try
{
is.close();
}
catch (IOException e)
{
e.printStackTrace();
}
}
return sb.toString();
}

public static class ResponseInfo
{
// 获取是否成功，failed 或 success
public String status;
// 如果获取成功了返回的数据信息
public String responseString;
// 如果失败了连接失败的错误信息
public String exceptionString;
}
}

HomePageInfo.java

package com.example.juren;

import java.util.ArrayList;

public class HomePageInfo
{

public ArrayList<CategoryInfo> categorys = new ArrayList<CategoryInfo>();

public String status;
}

CategoryInfo.java

package com.example.juren;

/*
* *"id": "1",
"name": "综合",
"icon": "http://114.55.116.95:8080/shusheng/images/zhonghe.png",
"short_desc": "十八般武器样样精通",
"desc": "NULL"
*/
public class CategoryInfo
{

public String id;
public String name;
public String icon;
public String short_desc;
public String desc;

}

LinearItemView.java 用来定义linearItemView_xml 元素，简化了ui的代码

package com.example.juren;

import android.content.Context;
import android.graphics.Bitmap;
import android.util.AttributeSet;
import android.util.Log;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import android.widget.TextView;

/*
* *子类必须要实现父类的至少一个构造器，系统默认一个无参的构造器
*/
public class LinearItemView extends RelativeLayout
{

public ImageView mImageView;
public TextView mTitle_one;
public TextView mTitle_two;
public TextView mTitle_three;

public LinearItemView(Context context, AttributeSet attrs)
{
super(context, attrs);
Log.i("item", "这是第二个构造器");
}

@Override
protected void onFinishInflate()
{
super.onFinishInflate();

mImageView = (ImageView) findViewById(R.id.image3);
mTitle_one = (TextView) findViewById(R.id.title);
mTitle_two = (TextView) findViewById(R.id.subhead);
mTitle_three = (TextView) findViewById(R.id.detal);

}

public void setDatas(String one,String two,String three)
{
mTitle_one.setText(one);
mTitle_two.setText(two);
mTitle_three.setText(three);

}

public void setIcons(Bitmap bmp)
{
mImageView.setImageBitmap(bmp);
}
}

GridItemView.java  同上

<pre class="java" name="code">package com.example.juren;

import android.content.Context;
import android.graphics.Bitmap;
import android.util.AttributeSet;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

public class GridItemView extends LinearLayout
{

public ImageView tImage;
public TextView tTitle;

public GridItemView(Context context, AttributeSet attrs)
{
super(context, attrs);
// TODO Auto-generated constructor stub
}

@Override
protected void onFinishInflate()
{
super.onFinishInflate();

tImage = (ImageView) findViewById(R.id.tIcon);
tTitle = (TextView) findViewById(R.id.tTitle);
}

public void setDatas(String one)
{
tTitle.setText(one);
}

public void setIcons(Bitmap bmp)
{
tImage.setImageBitmap(bmp);
}
}

activity_main.xml 对比后比原来简洁多了，可读性也高了

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#EFEFF4"
android:orientation="vertical" >

<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#FFFFFF"
android:gravity="center"
android:paddingBottom="14dp"
android:paddingTop="14dp"
android:text="@string/hello_world"
android:textColor="#666666"
android:textSize="17sp" />

<TextView
android:layout_width="match_parent"
android:layout_height="1dp" />

<ScrollView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:overScrollMode="never" >

<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:paddingBottom="7dp"
android:paddingTop="7dp" >

<include
android:id="@+id/include1"
layout="@layout/linear_item" />

<include
android:id="@+id/include2"
layout="@layout/linear_item" />

<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="11dp"
android:layout_marginRight="11dp"
android:orientation="horizontal" >

<include
android:id="@+id/include_1"
layout="@layout/grid_item" />

<include
android:id="@+id/include_2"
layout="@layout/grid_item" />

<include
android:id="@+id/include_3"
layout="@layout/grid_item" />
</LinearLayout>

<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="11dp"
android:layout_marginRight="11dp"
android:orientation="horizontal" >

<include
android:id="@+id/include_4"
layout="@layout/grid_item" />

<include
android:id="@+id/include_5"
layout="@layout/grid_item" />

<include
android:id="@+id/include_6"
layout="@layout/grid_item" />
</LinearLayout>

<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="11dp"
android:layout_marginRight="11dp"
android:orientation="horizontal" >

<include
android:id="@+id/include_7"
layout="@layout/grid_item" />

<include
android:id="@+id/include_8"
layout="@layout/grid_item" />

<include
android:id="@+id/include_9"
layout="@layout/grid_item" />
</LinearLayout>

</LinearLayout>
</ScrollView>

<TextView
android:layout_width="match_parent"
android:layout_height="1dp" />

</LinearLayout>

Linear_item.xml  是上面定义的include元素，

在activity_main中使用时要保证属性都一样，不一样的属性放到外层单独定义

注意下面最外层的使用方法：包名 + 类名

<com.example.juren.LinearItemView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="19dp"
android:layout_marginRight="19dp"
android:layout_marginTop="7dp"
android:layout_marginBottom="7dp"
android:background="@drawable/background" >

<ImageView
android:id="@+id/image3"
android:layout_width="58dp"
android:layout_height="58dp"
android:layout_alignParentLeft="true"
android:layout_margin="19dp"
android:src="@drawable/xxhl" />

<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_toLeftOf="@+id/image4"
android:layout_toRightOf="@id/image3"
android:orientation="vertical" >

<TextView
android:id="@+id/title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="left"
android:text="@string/hello"
android:textColor="#222222"
android:textSize="16sp" />

<TextView
android:id="@+id/subhead"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:gravity="left"
android:singleLine="true"
android:text="@string/hello1"
android:textColor="#cccccc"
android:textSize="12sp" />

<TextView
android:id="@+id/detal"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="left"
android:text="@string/hello2"
android:textColor="#cccccc"
android:textSize="12sp" />
</LinearLayout>

<ImageView
android:id="@+id/image4"
android:layout_width="21dp"
android:layout_height="21dp"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
android:layout_marginLeft="19dp"
android:layout_marginRight="19dp"
android:src="@drawable/xxhr" />

</com.example.juren.LinearItemView>

grid_item.xml  同上

<com.example.juren.GridItemView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="7dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginTop="7dp"
android:background="@drawable/background"
android:gravity="center_horizontal"
android:orientation="vertical" >

<ImageView
android:id="@+id/tIcon"
android:layout_width="58dp"
android:layout_height="58dp"
android:layout_marginLeft="19dp"
android:layout_marginRight="19dp"
android:layout_marginTop="19dp"
android:src="@drawable/xxhl" />

<TextView
android:id="@+id/tTitle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="19dp"
android:layout_marginTop="14dp"
android:text="@string/hello6"
android:textColor="#333333"
android:textSize="14dp" >
</TextView>

</com.example.juren.GridItemView>

改良后的代码如上，还需要完善继续改进...