安卓开发_数据存储技术_内部存储

 1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     xmlns:tools="http://schemas.android.com/tools"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:orientation="vertical"
 6     android:gravity="center_horizontal"
 7    >
 8     <LinearLayout 
 9         android:layout_width="match_parent"
10         android:layout_height="wrap_content"
11         android:orientation="horizontal">
12         
13         
14         
15     <EditText 
16         android:id="@+id/edit_filename"
17         android:layout_width="wrap_content"
18         android:layout_height="wrap_content"
19         android:hint="输入文件名"
20         />
21     
22     <Button 
23         android:id="@+id/btn_open"
24         android:layout_width="wrap_content"
25         android:layout_height="wrap_content"
26         android:text="打开"
27         />
28     <Button 
29         android:id="@+id/btn_save"
30         android:layout_width="wrap_content"
31         android:layout_height="wrap_content"
32         android:text="保存"
33         />
34     </LinearLayout>
35     
36     <EditText 
37         android:layout_width="match_parent"
38         android:layout_height="0dp"
39         android:gravity="left|top"
40         android:layout_weight="1"
41         android:hint="文件内容"
42         android:id="@+id/edit_content"
43         
44         />
45     
46     
47 </LinearLayout>

  1 package com.xqx_sharedata;
  2 
  3 import java.io.FileInputStream;
  4 import java.io.FileNotFoundException;
  5 import java.io.FileOutputStream;
  6 import java.io.IOException;
  7 import java.util.Arrays;
  8 
  9 import android.app.Activity;
 10 import android.app.AlertDialog;
 11 import android.os.Bundle;
 12 import android.view.View;
 13 import android.view.View.OnClickListener;
 14 import android.widget.ArrayAdapter;
 15 import android.widget.Button;
 16 import android.widget.EditText;
 17 
 18 public class MainActivity extends Activity implements OnClickListener {
 19 
 20     private Button btn_save; //保存按钮
 21     private Button btn_open; //打开按钮
 22     private EditText fileName; //文件名编辑框
 23     private EditText content; //文件内容编辑框
 24     @Override
 25     protected void onCreate(Bundle savedInstanceState) {
 26         super.onCreate(savedInstanceState);
 27         setContentView(R.layout.activity_main);
 28         
 29         btn_open = (Button) findViewById(R.id.btn_open);
 30         btn_save = (Button) findViewById(R.id.btn_save);
 31         fileName = (EditText) findViewById(R.id.edit_filename);
 32         content = (EditText) findViewById(R.id.edit_content);
 33         
 34         //俩按钮设置点击事件
 35         btn_open.setOnClickListener(this);
 36         btn_save.setOnClickListener(this);
 37     }
 38     //保存内容到文件中
 39     public void saveFile()
 40     {
 41         //保存的文件名，从编辑框得到
 42         String str_filename = fileName.getText().toString().trim();
 43         //保存的内容，从编辑框得到
 44         String str_filecontent = content.getText().toString().trim();
 45         //安卓给定的字节输出流
 46         FileOutputStream fos = null;
 47         //写
 48         try {
 49             //第一个参数是写入的文件名，第二个参数是内容形式，
 50             fos = openFileOutput(str_filename, MODE_PRIVATE);
 51             fos.write(str_filecontent.getBytes());
 52         
 53         } catch (FileNotFoundException e) {
 54             // TODO Auto-generated catch block
 55             e.printStackTrace();
 56         } catch (IOException e) {
 57             // TODO Auto-generated catch block
 58             e.printStackTrace();
 59         }
 60         try {
 61             fos.close();
 62         } catch (IOException e) {
 63             // TODO Auto-generated catch block
 64             e.printStackTrace();
 65         }
 66         
 67     }
 68     //读文件
 69     public void readFile() throws IOException
 70     {
 71         //编辑框中得到要读取的文件名
 72         String str_filename = fileName.getText().toString().trim();
 73         //读取文件
 74         FileInputStream fis = openFileInput(str_filename);
 75         byte arr[] = new byte[1024];
 76         int len=0;
 77         while((len = fis.read(arr))!=-1)
 78         {
 79             //将读取的数据添加到文本内容编辑框中
 80             content.append(new String(arr,0,len));
 81         }
 82         fis.close();
 83         
 84         
 85     }
 86     
 87 
 88     @Override
 89     public void onClick(View v) {
 90         // TODO Auto-generated method stub
 91         switch (v.getId()) {
 92         //打开文件
 93         case R.id.btn_open:
 94             try {
 95                 readFile();
 96             } catch (IOException e) {
 97                 // TODO Auto-generated catch block
 98                 e.printStackTrace();
 99             }
100             break;
101         //保存文件
102         case R.id.btn_save:
103                 saveFile();
104             break;
105 
106         default:
107             break;
108         }
109     }
110 }

 1 AlertDialog dialog ;
 2             
 3             ArrayAdapter<String> adapter = new ArrayAdapter<String>(MainActivity.this, android.R.layout.simple_list_item_1);
 4             adapter.addAll(Arrays.asList(fileList()));
 5             AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
 6             dialog = builder.setTitle("文件列表")
 7                     .setIcon(R.drawable.ic_launcher)
 8                     .setAdapter(adapter, null)
 9                     .setPositiveButton("确定", null)
10                     .create();
11             dialog.show();