Android 访问文件权限的四种模式介绍

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


xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="按钮1"
android:onClick="click1" />
</LinearLayout>

public void click1(View v) {
//data/data/com.wuyudong.permission.files
try {
FileOutputStream fos = openFileOutput("info1.txt", MODE_PRIVATE);
fos.write("私有模式".getBytes());
fos.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

package com.wuyudong.permission;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import android.os.Bundle;
import android.app.Activity;
import android.view.View;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void click1(View v) {
// data/data/com.wuyudong.permission.files
try {
FileOutputStream fos = openFileOutput("info1.txt", MODE_PRIVATE);
fos.write("私有模式".getBytes());
fos.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void click2(View v) {
// data/data/com.wuyudong.permission.files
try {
FileOutputStream fos = openFileOutput("info2.txt", MODE_APPEND);
fos.write("追加模式".getBytes());
fos.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void click3(View v) {
// data/data/com.wuyudong.permission.files
try {
FileOutputStream fos = openFileOutput("info3.txt", MODE_WORLD_READABLE);
fos.write("全局可读模式".getBytes());
fos.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void click4(View v) {
// data/data/com.wuyudong.permission.files
try {
FileOutputStream fos = openFileOutput("info4.txt", MODE_WORLD_WRITEABLE);
fos.write("私有模式".getBytes());
fos.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

package com.wuyudong.other;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStreamReader;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.Toast;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void click(View v) {
File file = new File("data/data/com.wuyudong.permission/files/info3.txt");
try {
FileInputStream fis = new FileInputStream(file);
//把字节流转换成字符流
BufferedReader br = new BufferedReader(new InputStreamReader(fis));
String text = br.readLine();
Toast.makeText(this, text, 0).show();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}