文件操作

界面设计：

<RelativeLayout 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" >    <TextView        android:id="@+id/textView1"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:text="@string/filename" />    <EditText        android:id="@+id/filecontent"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:layout_above="@+id/button"        android:layout_alignLeft="@+id/filename"        android:layout_marginBottom="33dp"        android:ems="10"        android:minLines="3" >        <requestFocus />    </EditText>    <EditText        android:id="@+id/filename"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:layout_alignLeft="@+id/textView1"        android:layout_below="@+id/textView1"        android:layout_marginTop="29dp"        android:ems="10" />    <Button        android:id="@+id/button"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignLeft="@+id/filename"        android:layout_alignParentBottom="true"        android:layout_marginBottom="154dp"        android:layout_marginLeft="29dp"        android:text="@string/button" />    <TextView        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:layout_above="@+id/filecontent"        android:layout_alignLeft="@+id/filecontent"        android:text="@string/filecontent" /></RelativeLayout>

MainActivity类：

package cn.file;import cn.service.FileService;import android.os.Bundle;import android.app.Activity;import android.view.Menu;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;public class MainActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);Button button=(Button) this.findViewById(R.id.button);button.setOnClickListener(new ButtonClickListener());}private final class ButtonClickListener implements View.OnClickListener{@Overridepublic void onClick(View v) {EditText filenameText=(EditText) findViewById(R.id.filename);EditText contentText=(EditText) findViewById(R.id.filecontent);String filename=filenameText.getText().toString();String content=contentText.getText().toString();FileService service=new FileService(getApplicationContext());try {service.save(filename,content);Toast.makeText(getApplicationContext(), R.string.success, 1).show();} catch (Exception e) {Toast.makeText(getApplicationContext(), R.string.fail, 1).show();e.printStackTrace();}}}@Overridepublic 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;}}

FileService类：

package cn.service;import java.io.ByteArrayInputStream;import java.io.ByteArrayOutputStream;import java.io.FileInputStream;import java.io.FileOutputStream;import android.content.Context;public class FileService {private Context context;    public FileService(Context context) {super();this.context = context;}/**     * 文件保存     * @param filename 文件名称     * @param content 文件内容     */public void save(String filename, String content) throws Exception {FileOutputStream outStream=context.openFileOutput(filename, Context.MODE_PRIVATE);outStream.write(content.getBytes());outStream.close();}}

运行结果：