承接
Android学习笔记6----------数据的存储与访问（1）
最后：
Activity的设计。
效果图：
import
java.io.IOException;
import
java.io.InputStream;
import
java.io.OutputStream;
import
Android.app.Activity;
import
Android.content.Context;
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;
import com.luku.file.service.FileService;
public class fileActivity extends Activity
{
private EditText editText=null;
private TextView content =null;
private TextView textView1=null;
private Button read=null;
private Button button =null;
private Button exit=null;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
textView1=(TextView)findViewById(R.id.textView1);
content=(TextView)findViewById(R.id.content);
editText=(EditText)findViewById(R.id.filename);
button=(Button)findViewById(R.id.baocun);
read=(Button)findViewById(R.id.read);
exit=(Button)findViewById(R.id.exit);
button.setOnClickListener(listener);
read.setOnClickListener(listener);
exit.setOnClickListener(listener);
}
private OnClickListener listener=new OnClickListener()
{
int resId = R.string.Success;
@Override
public void onClick(View v)
{
Button btn=(Button)v;
switch (btn.getId())
{
case R.id.baocun:
try
{
OutputStream stream=openFileOutput(editText.getText().toString(), Context.MODE_PRIVATE);
FileService.save(stream, content.getText().toString());
}
catch (IOException e)
{
e.printStackTrace();
resId = R.string.error;
Toast.makeText(fileActivity.this, resId, Toast.LENGTH_LONG).show();
}
Toast.makeText(fileActivity.this, resId, Toast.LENGTH_LONG).show();
break;
case R.id.read:
try
{
InputStream instream =openFileInput(editText.getText().toString());
String string=FileService.read(instream);
System.out.println(string);
textView1.setText(string.toString());
}
catch (Exception e)
{
Toast.makeText(fileActivity.this, "读取错误", Toast.LENGTH_LONG).show();
}
break;
case R.id.exit:
Android.os.Process.killProcess(
Android.os.Process.myPid());
break;
default:
break;
}
}
};
}
import
java.io.IOException;
import
java.io.InputStream;
import
java.io.OutputStream;
import
Android.app.Activity;
import
Android.content.Context;
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;
import com.luku.file.service.FileService;
public class fileActivity extends Activity
{
private EditText editText=null;
private TextView content =null;
private TextView textView1=null;
private Button read=null;
private Button button =null;
private Button exit=null;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
textView1=(TextView)findViewById(R.id.textView1);
content=(TextView)findViewById(R.id.content);
editText=(EditText)findViewById(R.id.filename);
button=(Button)findViewById(R.id.baocun);
read=(Button)findViewById(R.id.read);
exit=(Button)findViewById(R.id.exit);
button.setOnClickListener(listener);
read.setOnClickListener(listener);
exit.setOnClickListener(listener);
}
private OnClickListener listener=new OnClickListener()
{
int resId = R.string.Success;
@Override
public void onClick(View v)
{
Button btn=(Button)v;
switch (btn.getId())
{
case R.id.baocun:
try
{
OutputStream stream=openFileOutput(editText.getText().toString(), Context.MODE_PRIVATE);
FileService.save(stream, content.getText().toString());
}
catch (IOException e)
{
e.printStackTrace();
resId = R.string.error;
Toast.makeText(fileActivity.this, resId, Toast.LENGTH_LONG).show();
}
Toast.makeText(fileActivity.this, resId, Toast.LENGTH_LONG).show();
break;
case R.id.read:
try
{
InputStream instream =openFileInput(editText.getText().toString());
String string=FileService.read(instream);
System.out.println(string);
textView1.setText(string.toString());
}
catch (Exception e)
{
Toast.makeText(fileActivity.this, "读取错误", Toast.LENGTH_LONG).show();
}
break;
case R.id.exit:
Android.os.Process.killProcess(
Android.os.Process.myPid());
break;
default:
break;
}
}
};
}
main.xml文件
[
java]
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:
Android="http://schemas.
Android.com/apk/res/
Android"
Android:orientation="vertical"
Android:layout_width="fill_parent"
Android:layout_height="fill_parent"
>
<RelativeLayout xmlns:
Android="http://schemas.
Android.com/apk/res/
Android"
Android:orientation="vertical"
Android:layout_width="fill_parent"
Android:layout_height="wrap_content">
<TextView
Android:layout_width="90px"
Android:layout_height="wrap_content"
Android:text="文件名称:"
Android:textSize="21px"
Android:id="@+id/filenamelebal"
/>
<EditText
Android:layout_width="fill_parent"
Android:layout_height="wrap_content"
Android:layout_toRightOf="@id/filenamelebal"
Android:layout_alignTop="@id/filenamelebal"
Android:id="@+id/filename"
></EditText>
></RelativeLayout>
<TextView
Android:layout_width="90px"
Android:layout_height="wrap_content"
Android:text="内容:"
Android:textSize="21px"
/>
<EditText
Android:layout_width="fill_parent"
Android:layout_height="wrap_content"
Android:minLines="6"
Android:id="@+id/content"
></EditText>
<LinearLayout
Android:id="@+id/linearLayout1"
Android:layout_width="match_parent"
Android:layout_height="wrap_content">
<Button
Android:layout_height="wrap_content"
Android:id="@+id/baocun"
Android:text="保存"
Android:layout_width="wrap_content"></Button>
<Button
Android:text="读取"
Android:id="@+id/read"
Android:layout_width="wrap_content"
Android:layout_height="wrap_content"></Button>
<Button
Android:layout_width="wrap_content"
Android:text="退出"
Android:id="@+id/exit"
Android:layout_height="wrap_content"></Button>
</LinearLayout>
<TextView
Android:text="內容读取显示"
Android:id="@+id/textView1"
Android:layout_width="wrap_content"
Android:layout_height="wrap_content">
</TextView>
</LinearLayout>
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:
Android="http://schemas.
Android.com/apk/res/
Android"
Android:orientation="vertical"
Android:layout_width="fill_parent"
Android:layout_height="fill_parent"
>
<RelativeLayout xmlns:
Android="http://schemas.
Android.com/apk/res/
Android"
Android:orientation="vertical"
Android:layout_width="fill_parent"
Android:layout_height="wrap_content">
<TextView
Android:layout_width="90px"
Android:layout_height="wrap_content"
Android:text="文件名称:"
Android:textSize="21px"
Android:id="@+id/filenamelebal"
/>
<EditText
Android:layout_width="fill_parent"
Android:layout_height="wrap_content"
Android:layout_toRightOf="@id/filenamelebal"
Android:layout_alignTop="@id/filenamelebal"
Android:id="@+id/filename"
></EditText>
></RelativeLayout>
<TextView
Android:layout_width="90px"
Android:layout_height="wrap_content"
Android:text="内容:"
Android:textSize="21px"
/>
<EditText
Android:layout_width="fill_parent"
Android:layout_height="wrap_content"
Android:minLines="6"
Android:id="@+id/content"
></EditText>
<LinearLayout
Android:id="@+id/linearLayout1"
Android:layout_width="match_parent"
Android:layout_height="wrap_content">
<Button
Android:layout_height="wrap_content"
Android:id="@+id/baocun"
Android:text="保存"
Android:layout_width="wrap_content"></Button>
<Button
Android:text="读取"
Android:id="@+id/read"
Android:layout_width="wrap_content"
Android:layout_height="wrap_content"></Button>
<Button
Android:layout_width="wrap_content"
Android:text="退出"
Android:id="@+id/exit"
Android:layout_height="wrap_content"></Button>
</LinearLayout>
<TextView
Android:text="內容读取显示"
Android:id="@+id/textView1"
Android:layout_width="wrap_content"
Android:layout_height="wrap_content">
</TextView>
</LinearLayout>
FileService文件
[
java]
import
java.io.ByteArrayOutputStream;
import
java.io.IOException;
import
java.io.InputStream;
import
java.io.OutputStream;
public class FileService
{
/**
* 保存数据
*
* @param stream
* @param content
* @throws IOException
*/
public static void save(OutputStream stream, String content)
throws IOException
{
stream.write(content.getBytes());
stream.close();
}
/**
* 读取数据
*
* @param inStream
* @return
* @throws IOException
*/
public static String read(InputStream inStream) throws IOException
{
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
int len = -1;
byte[] buffer = new byte[1024];
while ((len = inStream.read(buffer)) != -1)
{
outputStream.write(buffer, 0, len);
}
byte[] data = outputStream.toByteArray();
inStream.close();
outputStream.close();
return new String(data);
}
import
java.io.ByteArrayOutputStream;
import
java.io.IOException;
import
java.io.InputStream;
import
java.io.OutputStream;
public class FileService
{
/**
* 保存数据
*
* @param stream
* @param content
* @throws IOException
*/
public static void save(OutputStream stream, String content)
throws IOException
{
stream.write(content.getBytes());
stream.close();
}
/**
* 读取数据
*
* @param inStream
* @return
* @throws IOException
*/
public static String read(InputStream inStream) throws IOException
{
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
int len = -1;
byte[] buffer = new byte[1024];
while ((len = inStream.read(buffer)) != -1)
{
outputStream.write(buffer, 0, len);
}
byte[] data = outputStream.toByteArray();
inStream.close();
outputStream.close();
return new String(data);
}
点击保存
点击读取
补充：使用文件的绝对路径访问文件
(1)
File file=new File("/data/data/包名/files/2.txt");
FileInputStream inStream=new FileInputStream(file);
Log.i("FileTest",readInStream(inStream));
(2)
把文件存入SD卡中
首先加入读写权限
SD卡创建与删除文件权限
<uses-permission
Android:name="
Android.permission.MOUNT_UNMOUNT_FILESYSTEMS"></uses-permission>
SD卡写入数据权限
<uses-permission
Android:name="
Android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>
