Android-下载网上图片 _Android

听闻少年二字，当与平庸相斥。这篇文章主要讲述Android-下载网上图片相关的知识，希望能为你提供帮助。

文章图片

下载操作相关代码：

package liudeli.async; import android.app.Activity; import android.app.ProgressDialog; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.view.View; import android.widget.ImageView; import android.widget.Toast; import java.io.InputStream; import java.net.HttpURLConnection; import java.net.URL; public class MainActivity3 extends Activity {// 图片地址 private final String PATH = "https://timgsa.baidu.com/timg?image& quality=80& size=b9999_10000" + "& sec=1544714792699& di=3c2de372608ed6323f583f1c1b445e51& imgtype=0& src=https://www.songbingjia.com/android/http%3A%2F%2Fp" + "2.qhimgs4.com%2Ft0105d27180a686e91f.jpg"; // 成功标识 private final int SUCCESS = 200; // 失败标识 private final int ERROR = 404; private ImageView imageView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main3); imageView = findViewById(R.id.iv_image); }/** * 定义Handler，用于接收子线程发过来的信息 */ private Handler mHandler = new Handler(){ @Override public void handleMessage(Message msg) { super.handleMessage(msg); switch (msg.what) { case SUCCESS: imageView.setImageBitmap((Bitmap) msg.obj); break; case ERROR: Toast.makeText(MainActivity3.this, "下载失败,请检查原因", Toast.LENGTH_LONG).show(); break; }if (null != progressDialog) progressDialog.dismiss(); } }; private ProgressDialog progressDialog = null; /** * 获取图片按钮 * @param view */ public void getImage(View view) { progressDialog = new ProgressDialog(MainActivity3.this); progressDialog.setMessage("正在下载..."); progressDialog.show(); // 开启子线程下载图片 /** * 执行此方法才去启动线程下载 */ new Thread(new DownloadImage()).start(); }class DownloadImage implements Runnable {/** * 发送Handler */ public void showUiImage(int responseCode, Bitmap bitmap) { Message message = mHandler.obtainMessage(responseCode); // 拿系统消息池的消息, 不要 new Message(); message.obj = bitmap; mHandler.sendMessageDelayed(message, 2000); }@Override public void run() { try { // 封装成网络地址 URL url = new URL(PATH); // 打开一个连接 HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection(); // 设置连接时长 httpURLConnection.setConnectTimeout(5000); // 设置请求方式 httpURLConnection.setRequestMethod("GET"); /** * 注意：?? 不要肤浅的任务打开连接对象设置连接时长设置请求方式就向服务器发送Http请求了 *是要执行httpURLConnection.getResponseCode()才会向服务器发送Http请求 */ if (httpURLConnection.getResponseCode() == HttpURLConnection.HTTP_OK) { // 得到服务器返回过来的流对象 InputStream inputStream = httpURLConnection.getInputStream(); Bitmap bitmap = BitmapFactory.decodeStream(inputStream); showUiImage(SUCCESS, bitmap); } else { showUiImage(ERROR, null); }} catch (Exception e) { e.printStackTrace(); showUiImage(ERROR, null); } } } }

【Android-下载网上图片】
Layout:

< ?xml version="1.0" encoding="utf-8"?> < RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent"> < Button android:id="@+id/bt_get_image" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="获取图片" android:onClick="getImage" /> < ImageView android:id="@+id/iv_image" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@id/bt_get_image" /> < /RelativeLayout>

AndroidManifest.xml 配置网络权限：