android的HTTP的使用（网络图片的获取）

效果图：

 

MainActivity

package com.huangfushi.hfs192025214_getpicture;

import android.graphics.Bitmap;
import android.os.Build;
import android.os.StrictMode;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    private EditText pathText;
    private ImageView imageView;

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

        if (Build.VERSION.SDK_INT > 9) {
            StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
            StrictMode.setThreadPolicy(policy);
        }
        pathText = (EditText) this.findViewById(R.id.path);
        imageView = (ImageView) this.findViewById(R.id.imageView);
    }

    public void showimage(View v) {
        String path = pathText.getText().toString();
        try {
            Bitmap bitmap = ImageService.getImage(path);
            imageView.setImageBitmap(bitmap);
        } catch (Exception e) {
            e.printStackTrace();
            Toast.makeText(getApplicationContext(), "网址错误", Toast.LENGTH_LONG).show();
        }
    }
}

XML：

ImageService

package com.huangfushi.hfs192025214_getpicture;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;

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

public class ImageService {


    public static Bitmap getImage(String path) throws Exception{
        URL url = new URL(path);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setConnectTimeout(5000);
        conn.setRequestMethod("GET");
        if(conn. getResponseCode() == 200){
            InputStream inStream = conn. getInputStream();
            Bitmap bitmap = BitmapFactory. decodeStream(inStream) ;
            return bitmap;
        }
        return null;
    }

}

一样要先获取网络权限：