19.Android之文件存储方法学习

Android开发中会用到文件存储，今天来学习下。

先改下布局界面：

 <?xml version="1.0" encoding="utf-8"?>

 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

     android:layout_width="match_parent"

     android:layout_height="match_parent"

     android:orientation="vertical" >

     <TextView

         android:id="@+id/filename"

         android:layout_width="wrap_content"

         android:layout_height="20dp"

         android:textSize="15dp"

         android:text="文件名称" />

     <EditText

         android:id="@+id/edit_name"

         android:layout_width="match_parent"

         android:layout_height="wrap_content"/>

     <TextView

         android:id="@+id/filecontent"

         android:layout_width="wrap_content"

         android:layout_height="20dp"

         android:textSize="15dp"

         android:text="文件内容" />

     <EditText

         android:id="@+id/edit_content"

         android:layout_width="match_parent"

         android:layout_height="wrap_content"/>

     <LinearLayout

         android:layout_width="match_parent"

         android:layout_height="match_parent"

         android:orientation="horizontal" >

         <Button

             android:id="@+id/btn_save"

             android:layout_width="wrap_content"

             android:layout_height="wrap_content"

             android:text="保存文件" />

         <Button

             android:id="@+id/btn_read"

             android:layout_width="wrap_content"

             android:layout_height="wrap_content"

             android:text="读取文件" />

     </LinearLayout>

 </LinearLayout>

再改下MainActivity文件：

 package com.example.filesave;

 import java.io.ByteArrayOutputStream;

 import java.io.FileInputStream;

 import java.io.FileOutputStream;

 import android.app.Activity;

 import android.content.Context;

 import android.os.Bundle;

 import android.view.View;

 import android.widget.Button;

 import android.widget.EditText;

 public class MainActivity extends Activity {

     private Context context = this;

     private Button btnsave = null;

     private Button btnread = null;

     private EditText editname = null;

     private EditText editcontent = null;

     @Override

     protected void onCreate(Bundle savedInstanceState) {

         super.onCreate(savedInstanceState);

         setContentView(R.layout.activity_main);

         btnsave = (Button) findViewById(R.id.btn_save);

         btnread = (Button) findViewById(R.id.btn_read);

         editname = (EditText) findViewById(R.id.edit_name);

         editcontent = (EditText) findViewById(R.id.edit_content);

         btnsave.setOnClickListener(new View.OnClickListener() {

             @Override

             public void onClick(View v) {

                 String filename = editname.getText().toString();

                 String filecontent = editcontent.getText().toString();

                 FileOutputStream out = null;

                 try {

                     out = context

                             .openFileOutput(filename, Context.MODE_PRIVATE);

                     out.write(filecontent.getBytes("UTF-8"));

                     editname.setText("已经保存名称!");

                     editcontent.setText("已经保存内容!");

                 } catch (Exception e) {

                     e.printStackTrace();

                 } finally {

                     try {

                         out.close();

                     } catch (Exception e) {

                         e.printStackTrace();

                     }

                 }

             }

         });

         btnread.setOnClickListener(new View.OnClickListener() {

             @Override

             public void onClick(View v) {

                 String filename = editname.getText().toString(); // 获得读取的文件的名称

                 FileInputStream in = null;

                 ByteArrayOutputStream bout = null;

                 byte[] buf = new byte[1024];

                 bout = new ByteArrayOutputStream();

                 int length = 0;

                 try {

                     in = context.openFileInput(filename); // 获得输入流

                     while ((length = in.read(buf)) != -1) {

                         bout.write(buf, 0, length);

                     }

                     byte[] content = bout.toByteArray();

                     editcontent.setText(new String(content, "UTF-8")); // 设置文本框为读取的内容

                 } catch (Exception e) {

                     e.printStackTrace();

                 }

                 editcontent.invalidate(); // 刷新屏幕

                 try {

                     in.close();

                     bout.close();

                 } catch (Exception e) {

                 }

             }

         });

     }

 }