android 中使用文件进行存储程序数据
注意，读写 sdcard 时，需要用到权限，具体代码如下
xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello" />
<EditText
android:id="@+id/et"
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:gravity ="left"
/>
<Button
android:id="@+id/btnr"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="read"
/>
<Button
android:id="@+id/btnw"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="write"
/>
<Button
android:id="@+id/btnsd"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="write to sdcard"
/>
<Button
android:id="@+id/btnwpro"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="write pro"
/>
<Button
android:id="@+id/btnrpro"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="read pro"
/>
</LinearLayout>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello" />
<EditText
android:id="@+id/et"
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:gravity ="left"
/>
<Button
android:id="@+id/btnr"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="read"
/>
<Button
android:id="@+id/btnw"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="write"
/>
<Button
android:id="@+id/btnsd"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="write to sdcard"
/>
<Button
android:id="@+id/btnwpro"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="write pro"
/>
<Button
android:id="@+id/btnrpro"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="read pro"
/>
</LinearLayout>
java 代码
package zziss.android.filetest;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Properties;
import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class FiletestActivity extends Activity implements View.OnClickListener {
/** Called when the activity is first created. */
private EditText et;
private Button btnr;
private Button btnw;
private Button btnwsd;
private Button btnwpro;
private Button btnrpro;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
et = (EditText)this.findViewById(R.id.et);
btnr = (Button)this.findViewById(R.id.btnr);
btnw = (Button)this.findViewById(R.id.btnw);
btnwsd = (Button)this.findViewById(R.id.btnsd);
btnwpro = (Button)this.findViewById(R.id.btnwpro);
btnrpro = (Button)this.findViewById(R.id.btnrpro);
btnw.setOnClickListener(this);
btnr.setOnClickListener(this);
btnwsd.setOnClickListener(this);
btnwpro.setOnClickListener(this);
btnrpro.setOnClickListener(this);
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (v.getId()==btnw.getId())
{
try {
FileOutputStream fot = openFileOutput("fc.dat",MODE_PRIVATE );
fot.write(et.getText().toString().getBytes());
fot.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
Toast toast = Toast.makeText(this,e.getMessage(), Toast.LENGTH_SHORT);
toast.show();
} catch (IOException e) {
// TODO Auto-generated catch block
Toast toast = Toast.makeText(this,e.getMessage(), Toast.LENGTH_SHORT);
toast.show();
}
}
if (v.getId()==btnr.getId())
{
try {
FileInputStream fot = openFileInput("fc.dat");
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] str = new byte[1024];
int len = -1;
while ((len=fot.read(str))>-1)
{
baos.write(str,0, len);
}
et.setText(baos.toString());
fot.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (v.getId()==btnwsd.getId())
{
// 查找 sdcard 状态
if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED))
{
File ff=this.getFileStreamPath("fc.dat");
File fpath=Environment.getExternalStorageDirectory();
File ft = new File(fpath,"fc.dat");
try {
FileOutputStream fos = new FileOutputStream(ft);
FileInputStream fis = new FileInputStream(ff);
int len=-1;
byte[] buf = new byte[1024];
while ( (len=fis.read(buf))>-1)
{
fos.write(buf,0,len);
}
fos.close();
fis.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
Toast toast = Toast.makeText(this,e.getMessage(), Toast.LENGTH_SHORT);
toast.show();
} catch (IOException e) {
// TODO Auto-generated catch block
Toast toast = Toast.makeText(this,e.getMessage(), Toast.LENGTH_SHORT);
toast.show();
}
}
} // end write to sdcard
if (v.getId()==btnwpro.getId())
{
Properties pro = new Properties();
pro.put("text", et.getText().toString());
try {
FileOutputStream fos = this.openFileOutput("fc.dat",MODE_PRIVATE);
pro.store(fos, "");
fos.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
Toast toast = Toast.makeText(this,e.getMessage(), Toast.LENGTH_SHORT);
toast.show();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
pro= null;
} // end write pro
if (v.getId()==btnrpro.getId())
{
Properties pro = new Properties();
try {
FileInputStream fis = this.openFileInput("fc.dat");
pro.load(fis);
fis.close();
et.setText(pro.getProperty("text"));
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
Toast toast = Toast.makeText(this,e.getMessage(), Toast.LENGTH_SHORT);
toast.show();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} // end read pro
}
}
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Properties;
import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class FiletestActivity extends Activity implements View.OnClickListener {
/** Called when the activity is first created. */
private EditText et;
private Button btnr;
private Button btnw;
private Button btnwsd;
private Button btnwpro;
private Button btnrpro;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
et = (EditText)this.findViewById(R.id.et);
btnr = (Button)this.findViewById(R.id.btnr);
btnw = (Button)this.findViewById(R.id.btnw);
btnwsd = (Button)this.findViewById(R.id.btnsd);
btnwpro = (Button)this.findViewById(R.id.btnwpro);
btnrpro = (Button)this.findViewById(R.id.btnrpro);
btnw.setOnClickListener(this);
btnr.setOnClickListener(this);
btnwsd.setOnClickListener(this);
btnwpro.setOnClickListener(this);
btnrpro.setOnClickListener(this);
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (v.getId()==btnw.getId())
{
try {
FileOutputStream fot = openFileOutput("fc.dat",MODE_PRIVATE );
fot.write(et.getText().toString().getBytes());
fot.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
Toast toast = Toast.makeText(this,e.getMessage(), Toast.LENGTH_SHORT);
toast.show();
} catch (IOException e) {
// TODO Auto-generated catch block
Toast toast = Toast.makeText(this,e.getMessage(), Toast.LENGTH_SHORT);
toast.show();
}
}
if (v.getId()==btnr.getId())
{
try {
FileInputStream fot = openFileInput("fc.dat");
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] str = new byte[1024];
int len = -1;
while ((len=fot.read(str))>-1)
{
baos.write(str,0, len);
}
et.setText(baos.toString());
fot.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (v.getId()==btnwsd.getId())
{
// 查找 sdcard 状态
if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED))
{
File ff=this.getFileStreamPath("fc.dat");
File fpath=Environment.getExternalStorageDirectory();
File ft = new File(fpath,"fc.dat");
try {
FileOutputStream fos = new FileOutputStream(ft);
FileInputStream fis = new FileInputStream(ff);
int len=-1;
byte[] buf = new byte[1024];
while ( (len=fis.read(buf))>-1)
{
fos.write(buf,0,len);
}
fos.close();
fis.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
Toast toast = Toast.makeText(this,e.getMessage(), Toast.LENGTH_SHORT);
toast.show();
} catch (IOException e) {
// TODO Auto-generated catch block
Toast toast = Toast.makeText(this,e.getMessage(), Toast.LENGTH_SHORT);
toast.show();
}
}
} // end write to sdcard
if (v.getId()==btnwpro.getId())
{
Properties pro = new Properties();
pro.put("text", et.getText().toString());
try {
FileOutputStream fos = this.openFileOutput("fc.dat",MODE_PRIVATE);
pro.store(fos, "");
fos.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
Toast toast = Toast.makeText(this,e.getMessage(), Toast.LENGTH_SHORT);
toast.show();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
pro= null;
} // end write pro
if (v.getId()==btnrpro.getId())
{
Properties pro = new Properties();
try {
FileInputStream fis = this.openFileInput("fc.dat");
pro.load(fis);
fis.close();
et.setText(pro.getProperty("text"));
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
Toast toast = Toast.makeText(this,e.getMessage(), Toast.LENGTH_SHORT);
toast.show();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} // end read pro
}
}
androidMain.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="zziss.android.filetest"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="14" />
<!-- 添加上读写存储卡 -->
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:label="@string/app_name"
android:name=".FiletestActivity" >
<intent-filter >
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="zziss.android.filetest"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="14" />
<!-- 添加上读写存储卡 -->
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:label="@string/app_name"
android:name=".FiletestActivity" >
<intent-filter >
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>