将一个文本文件写入到/data/data/应用名下的files文件夹下的info.txt文件里。
package com.example.test;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.PrintStream;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class MainActivity extends Activity {
private TextView textView;
private static final String FINEMAME = "info.txt";
private static final String DIR = "myfile";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
FileOutputStream outputStream = null;
try {
outputStream = super
.openFileOutput(FINEMAME, Activity.MODE_PRIVATE);
} catch (FileNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
PrintStream stream = null;
stream = new PrintStream(outputStream);
stream.println("姓名:");
stream.println("年龄:");
stream.println("性别:");
stream.println("职位:");
stream.close();
}
}
将info.txt文件中的内容读出到textview中
package com.example.test;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.util.Scanner;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class MainActivity extends Activity {
private TextView textView;
private static final String FINEMAME = "info.txt";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textView = (TextView) findViewById(R.id.textView);
File file = new File(FINEMAME);
FileInputStream inputStream = null;
try {
inputStream = super.openFileInput(FINEMAME);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Scanner scanner = new Scanner(inputStream);
StringBuffer sb = new StringBuffer();
while (scanner.hasNext()) {
sb.append(scanner.next()).append("\n");
}
scanner.close();
textView.setText(sb);
}
}
将数据写入到内存卡中,注意在android清单文件加入写sdcard的权限
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
package com.example.test;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.PrintStream;
import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.widget.TextView;
public class MainActivity extends Activity {
private TextView textView;
private static final String FINEMAME = "info.txt";
private static final String DIR = "myfile";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// 如果sd卡存在
if (Environment.getExternalStorageState().equals(
Environment.MEDIA_MOUNTED)) {
File file = new File(Environment.getExternalStorageDirectory()
+ File.separator + DIR + File.separator + FINEMAME);
// 如果目录不存在就创建目录
if (!file.getParentFile().exists()) {
file.getParentFile().mkdir();
}
PrintStream stream = null;
try {
stream = new PrintStream(new FileOutputStream(file));
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
stream.println("姓名:");
stream.println("年龄:");
stream.println("性别:");
stream.close();
}
}
}
从sdcard读取数据
package com.example.test;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.util.Scanner;
import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.widget.TextView;
public class MainActivity extends Activity {
private TextView textView;
private static final String FINEMAME = "info.txt";
private static final String DIR = "myfile";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// 如果sd卡存在
if (Environment.getExternalStorageState().equals(
Environment.MEDIA_MOUNTED)) {
textView = (TextView) findViewById(R.id.textView);
File file = new File(Environment.getExternalStorageDirectory()
+ File.separator + DIR + File.separator + FINEMAME);
FileInputStream inputStream = null;
Scanner scanner = null;
try {
scanner = new Scanner(new FileInputStream(file));
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
StringBuffer sb = new StringBuffer();
while (scanner.hasNext()) {
sb.append(scanner.next()).append("\n");
}
scanner.close();
textView.setText(sb);
}
}
}