1027

<LinearLayout 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=".MainActivity" 
    android:orientation="vertical">

    <TextView
        android:id="@+id/tv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="内部存储" />
    <EditText 
        android:id="@+id/et_out"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:hint="请输入您想要写入的内容" />
    <Button 
        android:id="@+id/btn_out"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="写入"
        android:onClick="click_out"/>
    <EditText 
        android:id="@+id/et_in"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:hint="读取的内容" />
    <Button 
        android:id="@+id/btn_in"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="click_in"
        android:text="读取" />
    

</LinearLayout>

package com.example.io;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {

    private EditText et_out;
    private EditText et_in;
    private TextView tv;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        et_out = (EditText)findViewById(R.id.et_out);
        et_in = (EditText)findViewById(R.id.et_in);
        tv = (TextView) findViewById(R.id.tv);
    }
    public void click_out(View view) {
        String fileName = "data.txt";
        String content = et_out.getText().toString();
        FileOutputStream fos = null;
        try {
            fos = openFileOutput(fileName, MODE_PRIVATE);
            fos.write(content.getBytes());
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally{
            try{
                if(fos!=null){
                    fos.close();
                }
            }catch(IOException e){
                e.printStackTrace();
            }
        }
        
        Toast.makeText(MainActivity.this, "写入"+content+"成功", Toast.LENGTH_SHORT).show();
    }

    public void click_in(View view) {
        String content = "";
        FileInputStream fis = null;
        try {
            fis = openFileInput("data.txt");
            byte[] buffer = new byte[fis.available()];
            fis.read(buffer);
            content = new String(buffer);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally{
            try {
                if(fis!=null){
                    fis.close();
                }
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            
        }
        
        et_in.setText(content);
        //tv.setText(content);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    
}