使用hander让图片发生改变

来源：互联网发布：怎样恢复360dns优化编辑：程序博客网时间：2024/05/22 15:31

布局文件：

<?xml version="1.0" encoding="utf-8"?>
<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">

    <ImageView
        android:id="@+id/image_view"
        android:scaleType="fitXY"
        android:layout_width="match_parent"
        android:layout_height="200dp" />
</RelativeLayout>

——————————————》activity代码

package news1510a.bawei.com.a17_demo;

import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.widget.ImageView;

import com.google.gson.Gson;
import com.nostra13.universalimageloader.core.ImageLoader;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    private ImageView imageView;
    private List<String> list = new ArrayList<>();

    private int index = 0;
    private Handler handler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            if (msg.what == 0){
                //街道消息之后,,,切换图片显示
                index ++;
                ImageLoader.getInstance().displayImage(list.get(index %list.size()),imageView,ImageLoaderUtil.getDefaultOption());

                //再次发送
                handler.sendEmptyMessageDelayed(0,3000);

            }
        }
    };

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

        imageView = (ImageView) findViewById(R.id.image_view);

        getDataFromNet();
    }

    private void getDataFromNet() {

        AsyncTask<Void, Void, String> asyncTask = new AsyncTask<Void, Void, String>() {
            @Override
            protected String doInBackground(Void... voids) {
                try {
                    URL url = new URL("http://apis.juhe.cn/cook/query?key=65481ae0fb17703c15a794aebaec93c5&menu=%E8%A5%BF%E7%BA%A2%E6%9F%BF&rn=10&pn=3");

                    HttpURLConnection connection = (HttpURLConnection) url.openConnection();

                    connection.setRequestMethod("GET");
                    connection.setReadTimeout(5000);
                    connection.setConnectTimeout(5000);

                    int responseCode = connection.getResponseCode();
                    if (responseCode == 200){
                        InputStream inputStream = connection.getInputStream();

                        String json = StringUtil.streamToString(inputStream,"utf-8");

                        return json;

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

                return null;
            }

            @Override
            protected void onPostExecute(String s) {
                //解析
                Gson gson = new Gson();
                DataDataBean dataDataBean = gson.fromJson(s, DataDataBean.class);

                List<DataDataBean.ResultBean.DataBean.StepsBean> steps = dataDataBean.getResult().getData().get(0).getSteps();

                for (DataDataBean.ResultBean.DataBean.StepsBean st: steps) {
                    list.add(st.getImg());
                }

                //现在图片集合有数据,,,,展示图片,,,展示第一张图片
                ImageLoader.getInstance().displayImage(list.get(0),imageView,ImageLoaderUtil.getDefaultOption());

                //发送延时消息
                handler.sendEmptyMessageDelayed(0,3000);
            }
        };

        asyncTask.execute();

    }
}

——————————工具类Stringutils类代码

public static String streamToString(InputStream inputStream, String charset) {
        try {
            InputStreamReader inputStreamReader = new InputStreamReader(inputStream,charset);

            BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
            String s = null;
            StringBuilder builder = new StringBuilder();
            while ((s = bufferedReader.readLine()) != null){
                builder.append(s);
            }

            bufferedReader.close();
            return builder.toString();

        } catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }

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