网络请求----简单框架使用------（百度图片下载实例）

1，Net网络请求类

package com.example.mylibrary;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Handler;
import android.util.Log;

import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.ProtocolException;
import java.net.URL;
import java.net.URLEncoder;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;

/**
* Created by alien on 2015/4/9.
*/
public class Net {
static Net instance;
private Net(){};
public static Net getInstance(){
if(instance==null){
instance=new Net();
}
return instance;
}

public interface CallBack{
void onCallBack(String result);
}
public interface BitmapCallBack{
void onBitmapCallBack(Bitmap bitmap);
}

//get请求:这里的请求参数必须写在string url里面，通过URL realurl=new URL(url);来访问地址
public void netGet(final String url ,final Map<String,String> params,final CallBack callBack){
final Handler handler=new Handler();
new Thread(new Runnable() {
@Override
public void run() {
try {
String requestData="";
if(params==null){
requestData=url;
}
if(params!=null){
requestData=url+"?";
for(Entry<String,String> entry:params.entrySet()){
requestData+=URLEncoder.encode(entry.getKey(),"UTF-8")+
"="+URLEncoder.encode(entry.getValue(),"UTF-8")+"&";
}

}
URL realurl=new URL(requestData);
HttpURLConnection connection= (HttpURLConnection) realurl.openConnection();
//貌似默认的是get请求
connection.setRequestMethod("GET");
//获取输入流(inputstream和outputstream是其他字节流的父类（抽象类）是不能直接new的
// 必须继承他，实例化它的子类)
InputStream in=connection.getInputStream();
ByteArrayOutputStream out=new ByteArrayOutputStream();
int a=0;
byte[] bytes=new byte[1024*20];
while ((a=in.read(bytes))!=-1){
out.write(bytes,0,a);
}
in.close();
out.flush();
out.close();
//toByteArray:返回这个流的当前内容作为一个字节数组。
final String result=new String(out.toByteArray());
handler.post(new Runnable() {
@Override
public void run() {
callBack.onCallBack(result);
}
});

} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}

}
}).start();

}

//post请求，这里的请求参数需要方法对应的输出流里面去请求网络(httpurlconnection)对应的outputstream

public void netPost(final String url, final Map<String,String> params, final CallBack callBack){
final Handler handler=new Handler();
new Thread(new Runnable() {

@Override
public void run() {
try{
InputStream in = null;
URL realurl = null;
String result = null;
String requestData="";
HttpURLConnection conn = null;
realurl = new URL(url);
conn = (HttpURLConnection)realurl.openConnection();
//post请求必须设置为true这下面的两个
conn.setDoOutput(true);
conn.setDoInput(true);
conn.setRequestMethod("POST");

if(params!=null){
for(Entry<String,String> entry:params.entrySet()){
requestData+= "&"+
URLEncoder.encode(entry.getKey(),"UTF-8")
+"="
+ URLEncoder.encode(entry.getValue(),"UTF-8");
}
}
//取出网络对应的输出流，这里转化为了字符流
PrintWriter pw = new PrintWriter(conn.getOutputStream());
pw.print(requestData);
pw.flush();
pw.close();
//                    //这里也可以不转化为字符流，直接写出字节流
//                    OutputStream out=conn.getOutputStream();
//                    out.write(requestData.getBytes());
//获取对应的输入流，然后取到返回的数据
in = conn.getInputStream();
BufferedReader bin = new BufferedReader(
new InputStreamReader(in));
String line;
while ((line = bin.readLine()) != null) {
result += line;
}
in.close();
final String finalResult = result;
handler.post(new Runnable() {
@Override
public void run() {
//这里通过回调去处理返回的数据
callBack.onCallBack(finalResult);
}
});

}catch(Exception eio){
eio.printStackTrace();
}
}
}).start();

}

public void netBitmap(final String url, final BitmapCallBack callBack){
final Handler handler=new Handler();
new Thread(new Runnable() {
@Override
public void run() {
URL realurl = null;
try {
realurl = new URL(url);
HttpURLConnection connection = (HttpURLConnection) realurl.openConnection();
//貌似默认的是get请求
connection.setRequestMethod("GET");
connection.setDoInput(true);
connection.connect();
//获取输入流(inputstream和outputstream是其他字节流的父类（抽象类）是不能直接new的
// 必须继承他，实例化它的子类)
InputStream in = connection.getInputStream();
final Bitmap bitmap = BitmapFactory.decodeStream(in);
in.close();
handler.post(new Runnable() {
@Override
public void run() {
callBack.onBitmapCallBack(bitmap);
}
});
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (ProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}

}).start();

}

}

2，百度的图片的获取

package com.example.downloadimg;

import android.content.Context;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.LinearLayout;

import com.example.mylibrary.Net;
import com.google.gson.Gson;

import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.List;

/**
* Created by alien on 2015/4/10.
*/
public class SearchImgActivity extends ActionBarActivity{
private RecyclerView mRecyclerView;
private EditText searchkey;
private ImageView img;
private List<ResponseData> responseDataList=new ArrayList<>();
private MyAdapter adapter=new MyAdapter();
private String url;
private int page=0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.searchimg_activity);

initview();
mRecyclerView.setAdapter(adapter);

img.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
page=0;
responseDataList.removeAll(responseDataList);
requestData();
}
});

}

private void initview(){
mRecyclerView= (RecyclerView) findViewById(R.id.recyclerview);
mRecyclerView.setLayoutManager(new StaggeredGridLayoutManager(2,StaggeredGridLayoutManager.VERTICAL));
searchkey= (EditText) findViewById(R.id.search_key);
img= (ImageView) findViewById(R.id.img_search);
}

public void requestData(){
try {
String word=URLEncoder.encode(searchkey.getText().toString(),"GBK");
url="http://image.baidu.com/i?tn=resultjson_com&word="+word+"&rn=10&pn="+page*20;
Log.i("test","url------------"+url);
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}

Net.getInstance().netGet(url,null,new Net.CallBack() {
@Override
public void onCallBack(String result) {

Log.i("test",result);
Gson gson=new Gson();
Data datas=gson.fromJson(result,Data.class);
Log.i("test","数组------"+datas.data.length);
if(datas!=null){
for(int i=0;i<datas.data.length;i++){
ResponseData responseData=datas.data[i];
responseDataList.add(responseData);
}
}
}
});
}

class MyAdapter extends RecyclerView.Adapter{

@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup viewGroup, int type) {
LayoutInflater inflater=LayoutInflater.from(SearchImgActivity.this);
View item=inflater.inflate(R.layout.recyclerview_img,viewGroup,false);
ImageViewHolder holder=new ImageViewHolder(item);
return holder;
}

@Override
public void onBindViewHolder(RecyclerView.ViewHolder viewHolder, int position) {
((ImageViewHolder)viewHolder).setData(responseDataList.get(position));
if((position+1)%11==0){
page++;
requestData();
Log.i("test","page-----"+page);
}
Log.i("test","position------"+position);
}

@Override
public int getItemCount() {
Log.i("test","长度---"+responseDataList.size()+"");
return responseDataList.size();
}

class ImageViewHolder extends RecyclerView.ViewHolder{
private ImageView item_img;
WindowManager manager= (WindowManager) getSystemService(Context.WINDOW_SERVICE);
final int width=manager.getDefaultDisplay().getWidth();
public ImageViewHolder(View itemView) {
super(itemView);
item_img= (ImageView) itemView.findViewById(R.id.item_img);

}
public void setData(final ResponseData data){
float percentage=(float)data.height/data.width;
item_img.setLayoutParams(new LinearLayout.LayoutParams(width/2,(int) (percentage*width/2)));
item_img.setImageBitmap(null);
Net.getInstance().netBitmap(data.thumbURL,new Net.BitmapCallBack() {

@Override
public void onBitmapCallBack(Bitmap bitmap) {
item_img.setImageBitmap(bitmap);

}
});
}
}
}

//json解析数据格式
private class ResponseData{

private String fromPageTitle,type,filesize,currentIndex,thumbURL;
private int width,height,pageNum;

public ResponseData(String fromPageTitle,String type,String currentIndex,String thumbURL,
String filesize, int pageNum ,int width,int height
){
this.thumbURL=thumbURL;
this.currentIndex=currentIndex;
this.filesize=filesize;
this.fromPageTitle=fromPageTitle;
this.height=height;
this.width=width;
this.pageNum=pageNum;
this.type=type;
}

}
private class Data{
private ResponseData[] data;
public Data(ResponseData[] data){
this.data=data;
}
}

}

这里用了recyclerview的serlayoutmanager，布局管理器是：new StaggeredGridLayoutManager(2,StaggeredGridLayoutManager.VERTICAL));

百度图片的接口：http://image.baidu.com/i?tn=resultjson_com&word=“+word+”&rn=10&pn=”+page*20