从URL图像下载到SD卡 [英] Download Images From URL to SD Card
本文介绍了从URL图像下载到SD卡的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我想创建一个非常简单的图片下载应用程序。其中我想从这个网址的所有图像下载到SD卡： https://www.dropbox.com/sh/5be3kgehyg8uzh2/AAA-jYcy_21nLBwnZQ3TBFAea
这code工作负载形象ImageView的：
包com.example.imagedownloadsample;
进口android.os.Bundle;
进口android.support.v7.app.ActionBarActivity;
进口android.widget.ImageView;
进口com.squareup.picasso.Picasso;
公共类MainActivity扩展ActionBarActivity {
@覆盖
保护无效的onCreate（包savedInstanceState）{
super.onCreate（savedInstanceState）;
的setContentView（R.layout.image_download）;
最后ImageView的IMG =（ImageView的）（findViewById（R.id.imageView1））;
//档案文件=新的文件（Environment.getExternalStorageDirectory（）
//的Android /数据/ com.usd.pop）;
Picasso.with（getApplicationContext（））
.load（http://8020.photos.jpgmag.com/3456318_294166_528c960558_m.jpg）
。走进（IMG）;
}
}
但是当我试图这样来下载图片到SD卡我最终与可惜的是应用程序停止错误：
包com.example.imagedownloadsample;
进口的java.io.File;
进口android.os.Bundle;
进口android.os.Environment;
进口android.support.v7.app.ActionBarActivity;
进口com.squareup.picasso.Picasso;
进口com.squareup.picasso.Target;
公共类MainActivity扩展ActionBarActivity {
@覆盖
保护无效的onCreate（包savedInstanceState）{
super.onCreate（savedInstanceState）;
的setContentView（R.layout.image_download）;
//最后ImageView的IMG =（ImageView的）（findViewById（R.id.imageView1））;
档案文件=新的文件（Environment.getExternalStorageDirectory（）
安卓/数据/ com.usd.pop）;
Picasso.with（getApplicationContext（））
.load（http://8020.photos.jpgmag.com/3456318_294166_528c960558_m.jpg）
。走进（（目标）文件）;
}
}
解决方案
您可以使用此的AsyncTask ，这样你就不会得到 OnMainThread 例外。
类DownloadFile扩展的AsyncTask＆LT;字符串，整数，龙＆GT; {
ProgressDialog mProgressDialog =新ProgressDialog（MainActivity.this）; //改变Mainactivity.this您的活动名称。
字符串strFolderName;
@覆盖
在preExecute保护无效（）{
super.on preExecute（）;
mProgressDialog.setMessage（下载）;
mProgressDialog.setIndeterminate（假）;
mProgressDialog.setMax（100）;
mProgressDialog.setCancelable（真正的）;
mProgressDialog.setProgressStyle（ProgressDialog.STYLE_HORIZONTAL）;
mProgressDialog.show（）;
}
@覆盖
保护龙doInBackground（字符串... aurl）{
诠释计数;
尝试 {
网址URL =新的URL（（字符串）aurl [0]）;
URLConnection的体conexion = url.openConnection（）;
conexion.connect（）;
字符串targetFileName =姓名+RAR。; //更改名称和子名称
INT lenghtOfFile = conexion.getContentLength（）;
字符串PATH = Environment.getExternalStorageDirectory（）+/+ downloadFolder +/;
文件夹=新的文件（路径）;
如果（！folder.exists（））{
folder.mkdir（）; //如果没有将被创建的文件夹。
}
的InputStream输入=新的BufferedInputStream（url.openStream（））;
的OutputStream输出=新的FileOutputStream（PATH + targetFileName）;
字节的数据[] =新的字节[1024];
总长= 0;
而（（计数= input.read（数据））！= - 1）{
共有+ =计数;
publishProgress（（int）的（总* 100 / lenghtOfFile））;
output.write（数据，0，计数）;
}
output.flush（）;
output.close（）;
input.close（）;
}赶上（例外五）{}
返回null;
}
保护无效onProgressUpdate（整数...进度）{
mProgressDialog.setProgress（进展[0]）;
如果（mProgressDialog.getProgress（）== mProgressDialog.getMax（））{
mProgressDialog.dismiss（）;
Toast.makeText（FA，文件下载，Toast.LENGTH_SHORT）.show（）;
}
}
保护无效onPostExecute（字符串结果）{
}
}
复制这个类到你的活动。它不能是在另一种方法。
和您可以调用这个像
新DownloadFile（）执行（yoururl）;
此外，将这些权限添加到您的清单。
＆LT;使用-权限的Android：名称=android.permission.INTERNET对＆GT; ＆LT; /使用-许可＆GT;
＆LT;使用-权限的Android：名称=android.permission.WRITE_EXTERNAL_STORAGE＆GT;＆LT; /使用-许可＆GT;
＆LT;使用-权限的Android：名称=android.permission.READ_PHONE_STATE＆GT;＆LT; /使用-许可＆GT;
I am trying to create a very simple Image Downloading app. in which i want to download all images from this url to sd card: https://www.dropbox.com/sh/5be3kgehyg8uzh2/AAA-jYcy_21nLBwnZQ3TBFAea
this code works to load image in imageview:
package com.example.imagedownloadsample;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.widget.ImageView;
import com.squareup.picasso.Picasso;
public class MainActivity extends ActionBarActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.image_download);
final ImageView img = (ImageView) (findViewById(R.id.imageView1));
// File file = new File(Environment.getExternalStorageDirectory(),
// "Android/data/com.usd.pop");
Picasso.with(getApplicationContext())
.load("http://8020.photos.jpgmag.com/3456318_294166_528c960558_m.jpg")
.into(img);
}
}
but when i tried like this to download image to sd card i end-up with unfortunatelly app stopped error:
package com.example.imagedownloadsample;
import java.io.File;
import android.os.Bundle;
import android.os.Environment;
import android.support.v7.app.ActionBarActivity;
import com.squareup.picasso.Picasso;
import com.squareup.picasso.Target;
public class MainActivity extends ActionBarActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.image_download);
//final ImageView img = (ImageView) (findViewById(R.id.imageView1));
File file = new File(Environment.getExternalStorageDirectory(),
"Android/data/com.usd.pop");
Picasso.with(getApplicationContext())
.load("http://8020.photos.jpgmag.com/3456318_294166_528c960558_m.jpg")
.into((Target) file);
}
}
解决方案
You can use this AsyncTask, so that you don't get OnMainThread exception.
class DownloadFile extends AsyncTask<String,Integer,Long> {
ProgressDialog mProgressDialog = new ProgressDialog(MainActivity.this);// Change Mainactivity.this with your activity name.
String strFolderName;
@Override
protected void onPreExecute() {
super.onPreExecute();
mProgressDialog.setMessage("Downloading");
mProgressDialog.setIndeterminate(false);
mProgressDialog.setMax(100);
mProgressDialog.setCancelable(true);
mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
mProgressDialog.show();
}
@Override
protected Long doInBackground(String... aurl) {
int count;
try {
URL url = new URL((String) aurl[0]);
URLConnection conexion = url.openConnection();
conexion.connect();
String targetFileName="Name"+".rar";//Change name and subname
int lenghtOfFile = conexion.getContentLength();
String PATH = Environment.getExternalStorageDirectory()+ "/"+downloadFolder+"/";
File folder = new File(PATH);
if(!folder.exists()){
folder.mkdir();//If there is no folder it will be created.
}
InputStream input = new BufferedInputStream(url.openStream());
OutputStream output = new FileOutputStream(PATH+targetFileName);
byte data[] = new byte[1024];
long total = 0;
while ((count = input.read(data)) != -1) {
total += count;
publishProgress ((int)(total*100/lenghtOfFile));
output.write(data, 0, count);
}
output.flush();
output.close();
input.close();
} catch (Exception e) {}
return null;
}
protected void onProgressUpdate(Integer... progress) {
mProgressDialog.setProgress(progress[0]);
if(mProgressDialog.getProgress()==mProgressDialog.getMax()){
mProgressDialog.dismiss();
Toast.makeText(fa, "File Downloaded", Toast.LENGTH_SHORT).show();
}
}
protected void onPostExecute(String result) {
}
}
Copy this class into your activity. It mustn't be in another method.
And you can call this like
new DownloadFile().execute("yoururl");
Also, add these permissions to your manifest.
<uses-permission android:name="android.permission.INTERNET"> </uses-permission>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>
<uses-permission android:name="android.permission.READ_PHONE_STATE"></uses-permission>
这篇关于从URL图像下载到SD卡的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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