使用AsyncTask实现网络的图片加载

来源：互联网发布：淘宝一分钱壁纸编辑：程序博客网时间：2024/05/22 03:24

清单列表

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

帮助类

public class ImageLoadAsyncTask extends AsyncTask<String,Void,Bitmap>{    /**     * 定义一个图片的接口回调     */    public interface ImageCallBack{        void callBitmap(Bitmap bitmap);    }    //定义变量记住调用者所传递进来的回调监听对象    private ImageCallBack imageCallBack;    //构造方法    public ImageLoadAsyncTask(ImageCallBack imageCallBack){        this.imageCallBack = imageCallBack;    }    @Override    protected void onPostExecute(Bitmap bitmap) {        super.onPostExecute(bitmap);        if(bitmap != null){            //设置图片 回调回去            imageCallBack.callBitmap(bitmap);        }    }    @Override    protected Bitmap doInBackground(String... params) {        try {            String path = params[0];            URL url = new URL(path);            HttpURLConnection connection = (HttpURLConnection) url.openConnection();            connection.setRequestMethod("GET");            connection.setConnectTimeout(5*1000);            connection.setReadTimeout(5*1000);            //服务器响应            int code = connection.getResponseCode();            if(code == HttpURLConnection.HTTP_OK){//判断服务器是否连接成功并相应                //图片流                InputStream is = connection.getInputStream();                //将图片流转化成Bitmap位图，返回                return BitmapFactory.decodeStream(is);            }        } catch (IOException e) {            e.printStackTrace();        }        return null;    }}

MainActivity类

public class MainActivity extends AppCompatActivity {    private ImageView ivIcon;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        //找到照片显示的控件id        ivIcon = (ImageView) findViewById(R.id.ivIcon);    }    //按钮的监听    public  void btnLoadImage(View v){        loadImg("http://20.1.3.46:8080/tomcat.png");    }    /**     * 加载图片     * @param url  图片地址     */    private void loadImg(String url){        ImageLoadAsyncTask imageLoadAsyncTask = new ImageLoadAsyncTask(new ImageLoadAsyncTask.ImageCallBack() {            @Override            public void callBitmap(Bitmap bitmap) {                if(bitmap != null){                    ivIcon.setImageBitmap(bitmap);                }            }        });        //执行图片请求        imageLoadAsyncTask.execute(url);    }}

0 0