<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:orientation="vertical" >  <TextView    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:text="文件名稱" />  <EditText     android:id="@+id/et_filename"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:hint="file name"    />  <TextView    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:text="文件內容" />  <EditText     android:id="@+id/et_filecontent"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:lines="7"    android:hint="file content"    />  <Button     android:id="@+id/btn_save"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:onClick="toSave"    android:text="Save"    />  <Button     android:id="@+id/btn_get"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:onClick="getFile"    android:text="Get"    /></LinearLayout>

package com.mark.storage;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 com.mark.service.FileService;public class MainActivity extends Activity {  private EditText mEt_filename,mEt_filecontent;  private Button mBtn_save;  private void init(){    mEt_filecontent = (EditText) findViewById(R.id.et_filecontent);    mEt_filename = (EditText) findViewById(R.id.et_filename);    mBtn_save = (Button) findViewById(R.id.btn_save);  }  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    init();  }  /**   * 保存數據到一個文件中   * @param view   */  public void toSave(View view) {    String fileName = mEt_filename.getText().toString();    String fileContent = mEt_filecontent.getText().toString();    FileService service = new FileService(getApplicationContext());    boolean isSucceed = service.save(fileName, fileContent);    if(isSucceed){      Toast.makeText(getApplicationContext(), "恭喜您保存文件成功！", Toast.LENGTH_SHORT).show();    }else{      Toast.makeText(getApplicationContext(), "對不起，您保存文件失敗！", Toast.LENGTH_SHORT).show();    }  }  public void getFile(View view){    String fileName = mEt_filename.getText().toString();    FileService service = new FileService(getApplicationContext());    String fileContent = service.getFile(fileName);    if(fileContent!=null || !fileContent.equals("")) {      mEt_filecontent.setText(fileContent);    }else{      Toast.makeText(getApplicationContext(), "對不起，讀取文件失??！", Toast.LENGTH_SHORT).show();    }  }}

package com.mark.service;import java.io.ByteArrayOutputStream;import java.io.FileInputStream;import java.io.FileOutputStream;import android.content.Context;public class FileService {  //android自帶的可以快速獲得文件輸出流的一個類，注意參數不能是路徑，只能是文件名稱  private Context mContext;  public FileService(Context context) {    this.mContext = context;  }  /**   * 保存文件的一個方法   * @param fileName   * @param fileContent   * @return   */  public boolean save(String fileName, String fileContent) {    try {      //采用Context.MODE_PRIVATE模式的話，只允許本應用訪問此文件，并且熟覆蓋式的添加數據      FileOutputStream fos = mContext.openFileOutput(fileName, Context.MODE_PRIVATE);      fos.write(fileContent.getBytes());      fos.close();      return true;    } catch (Exception e) {      e.printStackTrace();      return false;    }  }  /**   * 獲得之前保存過的文件的詳細的信息   * @param fileName   * @return   */  public String getFile(String fileName) {    String fileContent = "";    try{      FileInputStream fis = mContext.openFileInput(fileName);      byte[] buf = new byte[1024];      int len;      ByteArrayOutputStream bais = new ByteArrayOutputStream();      while((len = fis.read(buf))!= -1){        bais.write(buf, 0, len);      }      byte[] data = bais.toByteArray();      fileContent = new String(data);      fis.close();      return fileContent;    }catch(Exception e){      e.printStackTrace();      return "對不起，讀取文件失?。?;    }  }}