Android有进度条的下载图片并且显示图片
fmms
13年前
采用progressBar控件写一个有进度条的下载文件例子！下面的代码就是下载一个图片，并且把图片显示出来的代码： <p>layout文件布局很简单：</p> <pre class="brush:xml; toolbar: true; auto-links: false;"><?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" > <Button android:layout_width="fill_parent" android:layout_height="wrap_content" android:id="@+id/bt" android:text="开始下载文件" /> <ProgressBar android:id="@+id/pb" android:layout_width="fill_parent" style="?android:attr/progressBarStyleHorizontal" android:layout_height="wrap_content" /> <ImageView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/img"/> </LinearLayout></pre> <br /> 一个文件工具类： <pre class="brush:java; toolbar: true; auto-links: false;">package com.spring.sky.download; import java.io.File; import android.content.Context; import android.os.Environment; import android.util.Log; /** * 文件工具类 * @author spring sky * Email:vipa1888@163.com * QQ:840950105 * name:石明政 * */ public class FileUtil { /** * 检验SDcard状态 * @return boolean */ public static boolean checkSDCard() { if(android.os.Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED)) { return true; }else{ return false; } } /** * 保存文件文件到目录 * @param context * @return 文件保存的目录 */ public static String setMkdir(Context context) { String filePath; if(checkSDCard()) { filePath = Environment.getExternalStorageDirectory()+File.separator+"myfile"; }else{ filePath = context.getCacheDir().getAbsolutePath()+File.separator+"myfile"; } File file = new File(filePath); if(!file.exists()) { boolean b = file.mkdirs(); Log.e("file", "文件不存在 创建文件 "+b); }else{ Log.e("file", "文件存在"); } return filePath; } }</pre>下面就是界面上的逻辑处理: <pre class="brush:java; toolbar: true; auto-links: false;">package com.spring.sky.download; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.net.URL; import java.net.URLConnection; import android.app.Activity; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.util.Log; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.ImageView; import android.widget.ProgressBar; import android.widget.Toast; /** * 文件下载界面 * @author spring sky * Email:vipa1888@163.com * QQ:840950105 * name:石明政 * */ public class IndexActivity extends Activity implements OnClickListener{ private static final int DOWNLOAD_PREPARE = 0; private static final int DOWNLOAD_WORK = 1; private static final int DOWNLOAD_OK = 2; private static final int DOWNLOAD_ERROR =3; private static final String TAG = "IndexActivity"; private Button bt ; private ProgressBar pb; private ImageView img; /** * 需要下载的文件 * 注意：在模拟器上面使用无法解析有域名的主机 */ private String url = "http://61.155.165.32/shuixiyue/pic/item/f141247490d0e96fb251b963.jpg"; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); bt = (Button) this.findViewById(R.id.bt); bt.setOnClickListener(this); pb = (ProgressBar) this.findViewById(R.id.pb); pb.setVisibility(ProgressBar.INVISIBLE); img =(ImageView) this.findViewById(R.id.img); } /** * 按钮点击事件 */ @Override public void onClick(View v) { switch (v.getId()) { case R.id.bt: Toast.makeText(this, "开始下载文件", Toast.LENGTH_SHORT).show(); new Thread(){ @Override public void run() { downloadFile(); super.run(); } }.start(); break; } } /** * 文件下载 */ private void downloadFile() { try { URL u = new URL(url); URLConnection conn = u.openConnection(); conn.connect(); InputStream is = conn.getInputStream(); fileSize = conn.getContentLength(); if(fileSize<1||is==null) { sendMessage(DOWNLOAD_ERROR); }else{ sendMessage(DOWNLOAD_PREPARE); FileOutputStream fos = new FileOutputStream(getPath()); byte[] bytes = new byte[1024]; int len = -1; while((len = is.read(bytes))!=-1) { fos.write(bytes, 0, len); downloadSize+=len; sendMessage(DOWNLOAD_WORK); } sendMessage(DOWNLOAD_OK); is.close(); fos.close(); } } catch (Exception e) { sendMessage(DOWNLOAD_ERROR); e.printStackTrace(); } } /** * 文件一共的大小 */ int fileSize = 0; /** * 已经下载的大小 */ int downloadSize = 0; /** * handler处理消息 */ private Handler handler = new Handler(){ @Override public void handleMessage(Message msg) { switch (msg.what) { case DOWNLOAD_PREPARE: Toast.makeText(IndexActivity.this, "下载准备", Toast.LENGTH_SHORT).show(); pb.setVisibility(ProgressBar.VISIBLE); Log.e(TAG, "一共:"+fileSize); pb.setMax(fileSize); break; case DOWNLOAD_WORK: Log.e(TAG, "已下载:"+downloadSize); pb.setProgress(downloadSize); int res = downloadSize*100/fileSize; bt.setText("已下载："+res+"%"); break; case DOWNLOAD_OK: try { if(getPath().endsWith(".jpg")||getPath().endsWith(".png")){ FileInputStream fis = new FileInputStream(getPath()); img.setImageBitmap(BitmapFactory.decodeStream(fis)); } downloadSize = 0; fileSize = 0; } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } Toast.makeText(IndexActivity.this, "下载完成", Toast.LENGTH_SHORT).show(); break; case DOWNLOAD_ERROR: Toast.makeText(IndexActivity.this, "下载出错", Toast.LENGTH_SHORT).show(); break; } super.handleMessage(msg); } }; /** * 得到文件的保存路径 * @return * @throws IOException */ private String getPath() throws IOException { String path = FileUtil.setMkdir(this)+File.separator+url.substring(url.lastIndexOf("/")+1); return path; } /** * 给hand发送消息 * @param what */ private void sendMessage(int what) { Message m = new Message(); m.what = what; handler.sendMessage(m); } }</pre> <p></p> 转自： <a href="/misc/goto?guid=4959501016854237455" target="_blank">http://blog.csdn.net/vipa1888/article/details/7208956</a>