1.布局文件
[代码]xml代码：
1 2 3 4 5 | <linearlayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical">
<button android:="download" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="图片下载"> <imageview android:id="@+id/iv" android:layout_height="wrap_content" android:layout_width="wrap_content" android:layout_gravity="center"> </imageview></button></linearlayout> |
2.MainActivity.java
[代码]java代码：
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 | package com.example.day12_ex_01;
import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.net.HttpURLConnection; import java.net.URL;
import android.app.Activity; import android.app.ProgressDialog; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.os.AsyncTask; import android.os.Bundle; import android.os.Environment; import android.view.View; import android.widget.ImageView;
public class MainActivity extends Activity { ProgressDialog pd; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); pd=new ProgressDialog(this); pd.setTitle("图片下载"); pd.setMessage("正在下载....."); pd.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL); pd.setIndeterminate(false); pd.setCancelable(false); pd.setMax(100); }
public void download(View view){ pd.show(); new MyTask().execute(); } class MyTask extends AsyncTask<void,integer,void>{
@Override protected Void doInBackground(Void... params) { try { URL url=new URL("http://www.ytmfdw.com/image/img3.jpg"); HttpURLConnection conn=(HttpURLConnection) url.openConnection(); InputStream in=conn.getInputStream(); String path=Environment.getExternalStorageDirectory().getAbsolutePath()+"/a.jpg"; File file=new File(path); OutputStream out=new FileOutputStream(file); int totals=conn.getContentLength(); int sumCount=0; byte buffer[]=new byte[1024]; int len=-1; while((len=in.read(buffer))!=-1){ out.write(buffer,0,len); sumCount+=len; float per=sumCount*100f/totals; publishProgress((int)per); } out.flush(); out.close(); in.close(); conn.disconnect(); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return null; } @Override protected void onProgressUpdate(Integer... values) { // TODO Auto-generated method stub super.onProgressUpdate(values); pd.setProgress(values[0]); } @Override protected void onPostExecute(Void result) { // TODO Auto-generated method stub super.onPostExecute(result); if(pd!=null&&pd.isShowing()){ pd.dismiss(); } String path=Environment.getExternalStorageDirectory().getAbsolutePath()+"/a.jpg"; ImageView iv=(ImageView) findViewById(R.id.iv); Bitmap bt=BitmapFactory.decodeFile(path); iv.setImageBitmap(bt); } }
}</void,integer,void> |
原文链接：http://www.apkbus.com/blog-813041-61158.html
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