Android文件保存与读取

//MainActivity.classpackage com.example.file;import java.io.FileNotFoundException;import java.io.IOException;import com.example.Service.FileService;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.EditText;import android.widget.TextView;import android.widget.Toast;public class MainActivity extends Activity implements OnClickListener {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);Button button_save = (Button) this.findViewById(R.id.button_save);button_save.setOnClickListener(this);Button button_open = (Button) this.findViewById(R.id.button_open);button_open.setOnClickListener(this);}@Overridepublic void onClick(View v) {EditText filenameText = (EditText) this.findViewById(R.id.filename);String filename = filenameText.getText().toString();FileService service = new FileService(getApplicationContext());switch (v.getId()) {case R.id.button_save:EditText filecontentText = (EditText) this.findViewById(R.id.filecontent);String filecontent = filecontentText.getText().toString();try {service.save(filename, filecontent);Toast.makeText(getApplicationContext(), R.string.success, 1).show();} catch (FileNotFoundException e) {Toast.makeText(getApplicationContext(), R.string.fail, 1).show();e.printStackTrace();} catch (IOException e) {Toast.makeText(getApplicationContext(), R.string.fail, 1).show();e.printStackTrace();}break;case R.id.button_open:try {String content = service.read(filename);TextView contentText = (TextView) this.findViewById(R.id.opencontent);contentText.setText(content);} catch (IOException e) {e.printStackTrace();}}}}//FileService.javapackage com.example.Service;import java.io.ByteArrayOutputStream;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import android.content.Context;public class FileService {private Context context;/*   保存文件  *   @param filename 文件名称 *  @param filecontent 文件内容 */public void save(String filename, String filecontent) throws IOException {//私有操作模式：创建出来的文件只能被本应用访问，另外采用私有操作模式创建的文件，写入文件内容会覆盖FileOutputStream outStream = context.openFileOutput(filename, Context.MODE_PRIVATE);outStream.write(filecontent.getBytes());outStream.close();}public FileService(Context context) {this.context = context;}/*   读取文件  *   @param filename 文件名称 *   @return 文件内容 *  @throws Exception */public String read(String filename) throws IOException{FileInputStream inStream = context.openFileInput(filename);ByteArrayOutputStream outStream = new ByteArrayOutputStream();byte[] buffer = new byte[1024];int length=0;while((length = inStream.read(buffer))!=-1){outStream.write(buffer, 0, length);}byte[] data = outStream.toByteArray();return new String(data);}}//activity_main.xml<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="vertical"    android:layout_width="fill_parent"    android:layout_height="fill_parent"     >    <TextView        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:text="@string/filename" />    <EditText         android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:id="@+id/filename"/>  <TextView        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:text="@string/filecontent" />  <EditText     android:minLines="3"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:id="@+id/filecontent"/>      <RelativeLayout          android:layout_width="fill_parent"          android:layout_height="wrap_content">      <Button       android:layout_width="150dp"      android:layout_height="wrap_content"      android:text="@string/button_open"      android:id="@+id/button_open"      android:layout_marginLeft="10dp"/>        <Button       android:layout_width="150dp"      android:layout_height="wrap_content"      android:text="@string/button_save"      android:id="@+id/button_save"      android:layout_toRightOf="@id/button_open"/>     </RelativeLayout> <TextView        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:text="@string/readcontent" /> <TextView        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:id="@+id/opencontent"/></LinearLayout>//strings.xml<?xml version="1.0" encoding="utf-8"?><resources>    <string name="app_name">文件操作</string>    <string name="filecontent">文件内容</string>    <string name="filename">文件名称</string><string name="button_save">保存</string><string name="action_settings">Settings</string><string name="success">保存成功</string><string name="fail">保存失败</string><string name="button_open">打开</string><string name="readcontent">读取的文件内容</string></resources>

运行结果：