why stringbuffer doesnt work in this code?

Question

I have to xml.file

first :

<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".Text1" >

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="36dp"
        android:text="Button1" />



</RelativeLayout>

second :

<?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" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_alignParentTop="true"
        android:layout_marginRight="20dp"
        android:layout_marginTop="28dp"
        android:text="TextView" />

</RelativeLayout>

i have a txt.file in asset folder that its name is 12.txt i want when i press button1 in first xml.file i go to second xml.file and textview on it set with my txt.file in asset folder

code is :

public class Text2 extends Activity {
private TextView txt;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.text2);
        txt=(TextView)findViewById(R.id.textView1);


        FileInputStream fis=null;
        final StringBuffer buffer= new StringBuffer();

        try {
            fis = openFileInput("12.txt");
            DataInputStream dataIO = new DataInputStream(fis);
            String strLine = null;

            if ((strLine = dataIO.readLine()) != null) {
                buffer.append(strLine);
            }

            dataIO.close();
            fis.close();
        }
        catch  (Exception e) {  
        }
        txt.setText(buffer.toString());





    }





}

why it doesnt work ?? when i press button1 i go to second xml.file but textview is empty !!!

Remove the try/catch block - or probably more applicable, log the exception. If there is an exception, you'll never know about it. — user2864740, Mar 29 '14 at 07:02
`try { throw new Exception("Oops"); doImportantStuff() } catch (Exception e) {}` - `doImportantStuff` is never called, but we never find out because the exception was ignored! Now, I'm not saying that an exception *is* generated, but if it was, *you'd never know* (and could possibly end up with an empty StringBuffer). — user2864740, Mar 29 '14 at 07:07
Try to appropriately recover from the exception - and if you can't (or maybe even if you can), [log the exception](http://stackoverflow.com/questions/4341363/android-print-full-exception-backtrace-to-log). Be very careful about "blindly swallowing" exceptions. — user2864740, Mar 29 '14 at 07:15

score 0 · Answer 1 · answered Mar 29 '14 at 07:07

0

use like this code:

          FileInputStream fstream = new FileInputStream(Environment.getExternalStorageDirectory()+filenames));
          DataInputStream in = new DataInputStream(fstream);
          BufferedReader br = new BufferedReader(new InputStreamReader(in));
          String strLine;
          while ((strLine = br.readLine()) != null)   
          {
              arrayOfarray.add(strLine);
          }

answered Mar 29 '14 at 07:07

prakash

1,428
1
21
33

what is filenames in first line ??? my txt.file name is 12.txt – user3410344 Mar 29 '14 at 07:10
where your get the filename,use that the path. – prakash Mar 29 '14 at 07:12
12.txt is in my assets folder ...... so ??????? – user3410344 Mar 29 '14 at 07:14
use this code: `AssetManager am = context.getAssets(); InputStream is = am.open("test.txt");' – prakash Mar 29 '14 at 07:19
and then ??? txt.settext(is) ????? – user3410344 Mar 29 '14 at 07:22
you can use the arraylist used to store the all the string from the file.`txt.setText(arrayOfarray.get(0); arrayOfarray.clear();` – prakash Mar 29 '14 at 07:27

score 0 · Answer 2 · answered Mar 29 '14 at 07:07

My best guess is that program's running directory is not what you think it is, and openFileInput() is throwing an IOException because it can't find 12.txt. Your catch-all-do-nothing block is probably hiding an error. You probably want to log exception and abort. If you don't care about exceptional conditions crashing your program, you can use the following cheap trick to get a backtrace:

catch(Exception e)
{
    throw(new RuntimeException(e));
}

When I'm writing code that's supposed to be part of a project with high standards (as opposed to a one-off experiment or something), or that someone else will see, I would make MyIOException which subclasses RuntimeException (possibly through intermediate MyRuntimeException) and has an IOException member, then when I catch an IOException I throw a wrapped MyIOException, which has the benefit of letting my caller use class-based exception dispatch.

i replace your catch in my code but when i press on button this error appears : unfortunately text has stopped — user3410344, Mar 29 '14 at 07:16

sandy · Answer 3 · 2014-03-29T08:49:07.780

0

Sorry Dude !! I have edited it again, now it will run perfectly!!

 public class Text2 extends Activity {
        private TextView txt;

            @Override
            protected void onCreate(Bundle savedInstanceState) {
                // TODO Auto-generated method stub
                super.onCreate(savedInstanceState);
                setContentView(R.layout.text2);
                txt=(TextView)findViewById(R.id.textView1);  
         String mLine ="";  
        try {
                BufferedReader reader = new BufferedReader(
                    new InputStreamReader(getAssets().open("12.txt")));

                // do reading, usually loop until end of file reading  
                mLine = reader.readLine();


                reader.close();
            } catch (IOException e) {
                //log the exception
            }
            txt.setText(mLine)

         }





        }

edited Mar 29 '14 at 08:49

answered Mar 29 '14 at 07:10

sandy

201
1
7

have you tried this code??? – sandy Mar 29 '14 at 07:15
mLine cannot be resolved to a variable ....... this error appeared – user3410344 Mar 29 '14 at 07:20
I have edited answer !! Try it – sandy Mar 29 '14 at 07:27
i tried it but textview is empty ..... why ???? – user3410344 Mar 29 '14 at 07:47

score 0 · Accepted Answer · answered Mar 29 '14 at 07:21

0

Try this..

    txt=(TextView)findViewById(R.id.textView1);        

    AssetManager assetManager = getAssets();
    InputStream inputStream = null;
    try {
         inputStream = assetManager.open("12.txt");
         BufferedReader r = new BufferedReader(new InputStreamReader(inputStream));
         StringBuilder total = new StringBuilder();
         String line;
         while ((line = r.readLine()) != null) {
              total.append(line);
         }
         txt.setText(total.toString());
    }
    catch (IOException e){
         e.printStackTrace();
    }

answered Mar 29 '14 at 07:21

Hariharan

28,756
7
51
55

it works ... but the lines arent justify ..... is it notepad problem ??? how can i fix it ?? – user3410344 Mar 29 '14 at 07:35
@user3410344 may be change your TextView width as match_parent `android:layout_width="match_parent"` and try. – Hariharan Mar 29 '14 at 07:37
it doesnt work can i use pdf to solve it ?? i think it is notepad problem – user3410344 Mar 29 '14 at 07:43
@user3410344 k do it. Happy Coding. – Hariharan Mar 29 '14 at 07:47
can i use your code for pdf too ??? pdf is like notepad in code ??? – user3410344 Mar 29 '14 at 07:51
@user3410344 yes you can. – Hariharan Mar 29 '14 at 07:54
i use pdf that name is 12.pdf in assets .... in your code just i changed 12.txt to 12.pdf ..... but a black page appears not my pdf ...... why ????? – user3410344 Mar 29 '14 at 08:10

score 0 · Answer 5 · answered Mar 29 '14 at 07:28

Try this code. it works for me. so it will help you.

package com.example.answerquestion;

import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileWriter;
import java.io.PrintWriter;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity {

    Button btn;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        btn = (Button) findViewById(R.id.btn1);
        btn.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                File dir = new File(getFilesDir().getAbsolutePath());
                try{
                    PrintWriter out = new PrintWriter(new FileWriter(dir + "/test.txt"));
                    for (int i = 0; i < 20; i++) {
                        out.println("omg");
                    }
                    out.close();
                    File file = new File(getFilesDir().getAbsolutePath(), "/test.txt");
                    FileInputStream in = new FileInputStream(file);
                  //  FileInputStream fis=null;
                    final StringBuffer buffer= new StringBuffer();

                       // fis = openFileInput("12.txt");
                        DataInputStream dataIO = new DataInputStream(in);
                        String strLine = null;

                        if ((strLine = dataIO.readLine()) != null) {
                            buffer.append(strLine);
                        }

                        dataIO.close();
                        in.close();
                        System.out.print(buffer.toString());
                    }
                    catch  (Exception e) {  
                    }

                }

        });
    }

}

why stringbuffer doesnt work in this code?

5 Answers5