使用Thread+HttpClient+handler

package com.example.slx.slx12_30;

import android.content.Intent;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.GridView;

import com.google.gson.Gson;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;

import java.io.IOException;
import java.util.List;

//显示一个GridView列表，使用Thread+HttpClient+handler
public class ShowActivity extends AppCompatActivity {

private GridView gridview;
private String cid;
private Handler handler=new Handler(){
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
Shows shows=(Shows)msg.obj;
List<Shows.DataBean.ListBean> list = shows.getData().get(0).getList();
MyAdapter2 myAdapter2 = new MyAdapter2(ShowActivity.this, list);
gridview.setAdapter(myAdapter2);
}

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

gridview = findViewById(R.id.gridview);

Intent intent = getIntent();
cid = intent.getStringExtra("cid");

new Thread(){
@Override
public void run() {
DefaultHttpClient defaultHttpClient = new DefaultHttpClient();
HttpGet httpGet = new HttpGet("https://www.zhaoapi.cn/product/getProductCatagory?cid="+ cid);
try {
HttpResponse response = defaultHttpClient.execute(httpGet);
if(response.getStatusLine().getStatusCode()==200){
HttpEntity entity = response.getEntity();
String s = EntityUtils.toString(entity);
Gson gson = new Gson();
Shows shows = gson.fromJson(s, Shows.class);

Message obtain = Message.obtain();
obtain.obj = shows;
handler.sendMessage(obtain);

}

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

}
}

package com.example.slx.slx12_30;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.List;

/**
* Created by lenovo on 2017/12/30.
*/

public class MyAdapter2 extends BaseAdapter{
private Context context;
private List<Shows.DataBean.ListBean> list;

public MyAdapter2(Context context, List<Shows.DataBean.ListBean> list) {
this.context = context;
this.list = list;
}

@Override
public int getCount() {
return list.size();
}

@Override
public Object getItem(int i) {
return list.get(i);
}

@Override
public long getItemId(int i) {
return i;
}

@Override
public View getView(int i, View view, ViewGroup viewGroup) {
ViewHolder holder;
if(view==null){
view=View.inflate(context,R.layout.griditemlayout,null);
holder=new ViewHolder();
holder.imageview2=(ImageView)view.findViewById(R.id.imageview2);
holder.textview2=(TextView)view.findViewById(R.id.textview2);
view.setTag(holder);
}else {
holder=(ViewHolder)view.getTag();

}
holder.textview2.setText(list.get(i).getName());

MyPicTask myPicTask = new MyPicTask(holder.imageview2);
myPicTask.execute(list.get(i).getIcon());

return view;

}

public class ViewHolder{
TextView textview2;
ImageView imageview2;
}

public class MyPicTask extends AsyncTask<String,Void,Bitmap> {
private ImageView img;
public MyPicTask(ImageView img) {
this.img = img;
}
@Override
protected Bitmap doInBackground(String... strings) {

try {
URL url = new URL(strings[0]);
HttpURLConnection urlConnection = (HttpURLConnection)url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.setReadTimeout(5000);
urlConnection.setConnectTimeout(5000);
if(urlConnection.getResponseCode()==200) {
InputStream inputStream = urlConnection.getInputStream();
Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
return bitmap;
}
} catch (Exception e) {
e.printStackTrace();
}

return null;
}

@Override
protected void onPostExecute(Bitmap bitmap) {
if(bitmap==null){
img.setImageResource(R.mipmap.ic_launcher);
}else {
img.setImageBitmap(bitmap);
}
}
}
}