In this tutorial how to read data from the file in an Android Application is shown.<\/p>\n
We can read and write data in an internal memory as well as external memory of our mobile.<\/p>\n
When we read or write data in an external memory then we have to set permission in AndroidManifest.xml file, but when you read or write the data in internal memory then no permissions are required.<\/p>\n
The permission to set for external storage to read the data in external file is as below:<\/p>\n
<manifest><\/p>\n
<uses-permission android:name=”android:permission.READ_EXTERNAL_STORAGE”\/><\/p>\n
<\/manifest><\/p>\n
Write the above code after the <uses-sdk> tag and before the <application> tag.<\/p>\n
We can call openFileInput() method to get FileInputStream.<\/p>\n
This is the code for file internal storage.<\/p>\n
Code:<\/p>\n
activity_main.xml<\/p>\n
<RelativeLayout xmlns:android=”http:\/\/schemas.android.com\/apk\/res\/android”
\nxmlns:tools=”http:\/\/schemas.android.com\/tools”
\nandroid:layout_width=”match_parent”
\nandroid:layout_height=”match_parent”
\nandroid:paddingBottom=”@dimen\/activity_vertical_margin”
\nandroid:paddingLeft=”@dimen\/activity_horizontal_margin”
\nandroid:paddingRight=”@dimen\/activity_horizontal_margin”
\nandroid:paddingTop=”@dimen\/activity_vertical_margin”
\ntools:context=”.MainActivity” ><\/p>\n
<TextView
\nandroid:id=”@+id\/fdt2″
\nandroid:layout_width=”wrap_content”
\nandroid:layout_height=”wrap_content”
\nandroid:layout_alignParentTop=”true”
\nandroid:layout_centerHorizontal=”true”
\nandroid:layout_marginTop=”69dp”
\nandroid:text=”File I\/O Operations” \/><\/p>\n
<Button
\nandroid:id=”@+id\/view1″
\nandroid:layout_width=”wrap_content”
\nandroid:layout_height=”wrap_content”
\nandroid:layout_centerHorizontal=”true”
\nandroid:layout_centerVertical=”true”
\nandroid:onClick=”onFileView”
\nandroid:text=”View File” \/><\/p>\n
<\/RelativeLayout><\/p>\n
MainActivty.java<\/p>\n
package com.example.demo;<\/p>\n
import android.os.Bundle;
\nimport android.app.Activity;
\nimport android.content.Intent;
\nimport android.view.Menu;
\nimport android.view.View;<\/p>\n
public class MainActivity extends Activity{<\/p>\n
@Override
\nprotected void onCreate(Bundle savedInstanceState) {
\nsuper.onCreate(savedInstanceState);
\nsetContentView(R.layout.activity_main);
\n}<\/p>\n
public void onFileView(View v)
\n{
\nIntent in=new Intent(MainActivity.this,display.class);
\nstartActivity(in);
\n}<\/p>\n
@Override
\npublic boolean onCreateOptionsMenu(Menu menu) {
\n\/\/Inflate the menu; this adds items to the action bar if it is present.
\ngetMenuInflater().inflate(R.menu.main, menu);
\nreturn true;
\n}
\n}<\/p>\n
res\/layout\/display_layout.xml<\/p>\n
<?xml version=”1.0″ encoding=”utf-8″?>
\n<RelativeLayout xmlns:android=”http:\/\/schemas.android.com\/apk\/res\/android”
\nandroid:layout_width=”match_parent”
\nandroid:layout_height=”match_parent” ><\/p>\n
<EditText
\nandroid:id=”@+id\/fnm2″
\nandroid:layout_width=”wrap_content”
\nandroid:layout_height=”wrap_content”
\nandroid:layout_alignParentTop=”true”
\nandroid:layout_centerHorizontal=”true”
\nandroid:layout_marginTop=”78dp”
\nandroid:ems=”10″
\nandroid:hint=”Enter the File Name” ><\/p>\n
<requestFocus \/>
\n<\/EditText><\/p>\n
<TextView
\nandroid:id=”@+id\/fdt2″
\nandroid:layout_width=”wrap_content”
\nandroid:layout_height=”wrap_content”
\nandroid:layout_below=”@+id\/fnm2″
\nandroid:layout_centerHorizontal=”true”
\nandroid:layout_marginTop=”51dp” \/><\/p>\n
<Button
\nandroid:id=”@+id\/back2″
\nandroid:layout_width=”wrap_content”
\nandroid:layout_height=”wrap_content”
\nandroid:layout_alignBaseline=”@+id\/display”
\nandroid:layout_alignBottom=”@+id\/display”
\nandroid:layout_alignRight=”@+id\/fnm2″
\nandroid:onClick=”back”
\nandroid:text=”Back” \/><\/p>\n
<Button
\nandroid:id=”@+id\/display”
\nandroid:layout_width=”wrap_content”
\nandroid:layout_height=”wrap_content”
\nandroid:layout_alignLeft=”@+id\/fnm2″
\nandroid:layout_below=”@+id\/fdt2″
\nandroid:layout_marginTop=”78dp”
\nandroid:onClick=”displayf”
\nandroid:text=”View File” \/><\/p>\n
<\/RelativeLayout><\/p>\n
src\/com.package.demo\/display.java<\/p>\n
package com.example.demo;<\/p>\n
import java.io.FileInputStream;<\/p>\n
import android.app.Activity;
\nimport android.content.Intent;
\nimport android.os.Bundle;
\nimport android.view.View;
\nimport android.widget.EditText;
\nimport android.widget.TextView;
\nimport android.widget.Toast;<\/p>\n
public class display extends Activity{
\nFileInputStream fIn;
\nEditText fnm;
\nTextView dt2;
\nString fname;<\/p>\n
@Override
\nprotected void onCreate(Bundle savedInstanceState) {
\nsuper.onCreate(savedInstanceState);
\nsetContentView(R.layout.display_layout);
\nfnm=(EditText)findViewById(R.id.fnm2);
\ndt2=(TextView)findViewById(R.id.fdt2);
\n}<\/p>\n
public void displayf(View v) throws Exception
\n{
\ntry{
\nfname=fnm.getText().toString();
\nfIn=openFileInput(fname);
\nint c;
\nString temp=””;
\nwhile((c=fIn.read())!=-1)
\n{
\ntemp=temp+Character.toString((char)c);
\n}
\ndt2.setText(temp);
\nToast.makeText(getBaseContext(), “File data read successfully”, Toast.LENGTH_SHORT).show();
\nfIn.close();
\n}
\ncatch(Exception e)
\n{
\ne.printStackTrace();
\n}
\nfinally
\n{
\nfIn.close();
\n}
\n}<\/p>\n
public void back(View v)
\n{
\nIntent in=new Intent(this,MainActivity.class);
\nstartActivity(in);
\n}
\n}<\/p>\n
AndroidManifest.xml<\/p>\n
<?xml version=”1.0″ encoding=”utf-8″?>
\n<manifest xmlns:android=”http:\/\/schemas.android.com\/apk\/res\/android”
\npackage=”com.example.demo”
\nandroid:versionCode=”1″
\nandroid:versionName=”1.0″ ><\/p>\n
<uses-sdk
\nandroid:minSdkVersion=”8″
\nandroid:targetSdkVersion=”17″ \/><\/p>\n
<application
\nandroid:allowBackup=”true”
\nandroid:icon=”@drawable\/ic_launcher”
\nandroid:label=”@string\/app_name”
\nandroid:theme=”@style\/AppTheme” >
\n<activity
\nandroid:name=”com.example.demo.MainActivity”
\nandroid:label=”@string\/app_name” >
\n<intent-filter>
\n<action android:name=”android.intent.action.MAIN” \/><\/p>\n
<category android:name=”android.intent.category.LAUNCHER” \/>
\n<\/intent-filter>
\n<\/activity>
\n<activity android:name=”.display”><\/activity>
\n<\/application><\/p>\n
<\/manifest><\/p>\n