安卓实现从互联网上获取图片并保存到本地目录中

不念不忘少年蓝@ 2022-09-20 15:02 165阅读 0赞

因为是对互联网和内存操作，所以我们要添加如下权限:

<uses-permission android:name="android.permission.INTERNET"/>

<uses-permission android:name="android.permission.WRITE\_EXTERNAL\_STORAGE"/>

//代码如下所示:

package com.itfom.getpicfromnet;
    
    import java.io.File;
    import java.io.FileOutputStream;
    import java.io.InputStream;
    import java.net.HttpURLConnection;
    import java.net.URL;
    
    import android.annotation.SuppressLint;
    import android.app.Activity;
    import android.graphics.BitmapFactory;
    import android.os.Bundle;
    import android.os.Environment;
    import android.os.Handler;
    import android.os.Message;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.widget.Button;
    import android.widget.ImageView;
    
    @SuppressLint("HandlerLeak")
    public class MainActivity extends Activity {
    
    	private ImageView iv_pic;
    	private Button btn_get;
    	@Override
    	protected void onCreate(Bundle savedInstanceState) {
    		super.onCreate(savedInstanceState);
    		setContentView(R.layout.activity_main);
    		btn_get = (Button) findViewById(R.id.btn_get);
    		iv_pic = (ImageView) findViewById(R.id.iv_img);
    		//设置监听事件
    		btn_get.setOnClickListener(new OnClickListener() {
    
    			@Override
    			public void onClick(View v) {
    				//开启子线程
    				new Thread(){
    					public void run() {
    						try {
    							String urlPath = "http://pic7.nipic.com/20100607/4791134_172835008083_2.jpg";
    							URL url = new URL(urlPath);
    							HttpURLConnection conn = (HttpURLConnection) url.openConnection();
    							conn.setConnectTimeout(6*1000);  // 注意要设置超时，设置时间不要超过10秒，避免被android系统回收
    							if (conn.getResponseCode() != 200) throw new RuntimeException("请求url失败");
    							InputStream inSream = conn.getInputStream();
    							//把图片保存到项目的根目录
    							readAsFile(inSream, new File(Environment.getExternalStorageDirectory()+"/"+"test.jpg"));
    							Message msg=new Message();
    							msg.what=0;
    							handler.sendMessage(msg);
    						} catch (Exception e) {
    							e.printStackTrace();
    						}
    					};
    				}.start();
    			}
    		});
    	}
    	public static void readAsFile(InputStream inSream, File file) throws Exception{
    		FileOutputStream outStream = new FileOutputStream(file);
    		byte[] buffer = new byte[1024];
    		int len = -1;
    		while( (len = inSream.read(buffer)) != -1 ){
    			outStream.write(buffer, 0, len);
    		}
    		outStream.close();
    		inSream.close();
    	}
    	//创建Handler
    	Handler handler=new Handler(){
    		public void handleMessage(android.os.Message msg) {
    			if(msg.what==0){
    				//开始绑定数据
    				iv_pic.setImageBitmap(BitmapFactory.decodeFile(Environment.getExternalStorageDirectory()+"/test.jpg"));
    			}
    		};
    	};
    }

运行结果如下所示:

![Center][]

[Center]: /images/20220828/304dba5c8d0f4e48813fe69056879fba.png