[英]Android - How can I read a text file from a url?
我上传了一个文本文件(* .txt)到服务器,现在我想读取文本文件...
没试好我试过这个例子。
ArrayList<String> urls=new ArrayList<String>(); //to read each line
TextView t; //to show the result
try {
// Create a URL for the desired page
URL url = new URL("mydomainname.de/test.txt"); //My text file location
// Read all the text returned by the server
BufferedReader in = new BufferedReader(new InputStreamReader(url.openStream()));
t=(TextView)findViewById(R.id.TextView1);
String str;
while ((str = in.readLine()) != null) {
urls.add(str);
}
in.close();
} catch (MalformedURLException e) {
} catch (IOException e) {
}
t.setText(urls.get(0)); // My TextFile has 3 lines
应用程序正在关闭......它可以取决于域名吗? 应该有IP吗? 我发现while循环没有被执行。 因为如果我将t.setText *放在while循环中则没有错误,并且TextView为空。 LogCat错误: http : t.setText(urls.get(0));
它用t.setText(urls.get(0));
突出显示该行t.setText(urls.get(0));
提前致谢 !!!
尝试使用HTTPUrlConnection或OKHTTP请求获取信息,请尝试以下操作:
总是在后台线程中做任何类型的网络,否则android将抛出NetworkOnMainThread异常
new Thread(new Runnable(){
public void run(){
ArrayList<String> urls=new ArrayList<String>(); //to read each line
//TextView t; //to show the result, please declare and find it inside onCreate()
try {
// Create a URL for the desired page
URL url = new URL("http://somevaliddomain.com/somevalidfile"); //My text file location
//First open the connection
HttpURLConnection conn=(HttpURLConnection) url.openConnection();
conn.setConnectTimeout(60000); // timing out in a minute
BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
//t=(TextView)findViewById(R.id.TextView1); // ideally do this in onCreate()
String str;
while ((str = in.readLine()) != null) {
urls.add(str);
}
in.close();
} catch (Exception e) {
Log.d("MyTag",e.toString());
}
//since we are in background thread, to post results we have to go back to ui thread. do the following for that
Activity.this.runOnUiThread(new Runnable(){
public void run(){
t.setText(urls.get(0)); // My TextFile has 3 lines
}
});
}
}).start();
1-)为您的清单文件添加Internet权限。
2-)确保在单独的线程中启动代码。
这是对我很有用的片段。
public List<String> getTextFromWeb(String urlString)
{
URLConnection feedUrl;
List<String> placeAddress = new ArrayList<>();
try
{
feedUrl = new URL(urlString).openConnection();
InputStream is = feedUrl.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(is, "UTF-8"));
String line = null;
while ((line = reader.readLine()) != null) // read line by line
{
placeAddress.add(line); // add line to list
}
is.close(); // close input stream
return placeAddress; // return whatever you need
}
catch (Exception e)
{
e.printStackTrace();
}
return null;
}
我们的读者功能已准备就绪,让我们通过另一个线程来调用它
new Thread(new Runnable()
{
public void run()
{
final List<String> addressList = getTextFromWeb("http://www.google.com/sometext.txt"); // format your URL
runOnUiThread(new Runnable()
{
@Override
public void run()
{
//update ui
}
});
}
}).start();
声明一个字符串变量来保存文本:
public String txt;
声明一种检查连通性的方法:
private boolean isNetworkConnected() {
ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
return cm.getActiveNetworkInfo() != null;
}
像这样delare AsyncTask:
private class ReadFileTask extends AsyncTask<String,Integer,Void> {
protected Void doInBackground(String...params){
URL url;
try {
//create url object to point to the file location on internet
url = new URL(params[0]);
//make a request to server
HttpURLConnection con=(HttpURLConnection)url.openConnection();
//get InputStream instance
InputStream is=con.getInputStream();
//create BufferedReader object
BufferedReader br=new BufferedReader(new InputStreamReader(is));
String line;
//read content of the file line by line
while((line=br.readLine())!=null){
txt+=line;
}
br.close();
}catch (Exception e) {
e.printStackTrace();
//close dialog if error occurs
}
return null;
}
现在使用所需的Url调用AsyncTask:
if(isNetworkConnected())
{
ReadFileTask tsk=new ReadFileTask ();
tsk.execute("http://mystite.com/test.txt");
}
并且不要忘记在Manifest中添加以下权限:
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
只需将其放入一个新线程并启动它将工作的线程。
new Thread(new Runnable()
{
@Override
public void run()
{
try
{
URL url = new URL("https://texts-8e2bd.firebaseapp.com/");//my app link change it
HttpsURLConnection uc = (HttpsURLConnection) url.openConnection();
BufferedReader br = new BufferedReader(new InputStreamReader(uc.getInputStream()));
String line;
StringBuilder lin2 = new StringBuilder();
while ((line = br.readLine()) != null)
{
lin2.append(line);
}
Log.d("texts", "onClick: "+lin2);
} catch (IOException e)
{
Log.d("texts", "onClick: "+e.getLocalizedMessage());
e.printStackTrace();
}
}
}).start();
而已。
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