File read and write : File « File « Android






  1. Android
  2. File
  3. File

File read and write

    

/***
  Copyright (c) 2008-2009 CommonsWare, LLC
  
  Licensed under the Apache License, Version 2.0 (the "License"); you may
  not use this file except in compliance with the License. You may obtain
  a copy of the License at
    http://www.apache.org/licenses/LICENSE-2.0
  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
*/

package app.test;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import java.io.BufferedReader;
import java.io.File;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;

public class Test extends Activity {
  private final static String NOTES="notes.txt";
  private EditText editor;
  
  @Override
  public void onCreate(Bundle icicle) {
    super.onCreate(icicle);
    setContentView(R.layout.main);
    editor=(EditText)findViewById(R.id.editor);
    
    Button btn=(Button)findViewById(R.id.close);
    
    btn.setOnClickListener(new Button.OnClickListener() {
      public void onClick(View v) {
        finish();
      }
    });
  }
  
  public void onResume() {
    super.onResume();
    
    try {
      InputStream in=openFileInput(NOTES);
      
      if (in!=null) {
        InputStreamReader tmp=new InputStreamReader(in);
        BufferedReader reader=new BufferedReader(tmp);
        String str;
        StringBuilder buf=new StringBuilder();
        
        while ((str = reader.readLine()) != null) {
          buf.append(str+"\n");
        }
        
        in.close();
        editor.setText(buf.toString());
      }
    }
    catch (java.io.FileNotFoundException e) {
      // that's OK, we probably haven't created it yet
    }
    catch (Throwable t) {
      Toast
        .makeText(this, "Exception: "+t.toString(), 2000)
        .show();
    }
  }
  
  public void onPause() {
    super.onPause();
    
    try {
      OutputStreamWriter out=
          new OutputStreamWriter(openFileOutput(NOTES, 0));
      
      out.write(editor.getText().toString());
      out.close();    
    }
    catch (Throwable t) {
      Toast
        .makeText(this, "Exception: "+t.toString(), 2000)
        .show();
    }
  }
}


//main.xml


<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="fill_parent" 
  android:layout_height="fill_parent"
  android:orientation="vertical">
  <Button android:id="@+id/close"
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content"
    android:text="Close" />
  <EditText
    android:id="@+id/editor"
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent"
    android:singleLine="false"
    android:gravity="top"
    />
</LinearLayout>








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