Android开发技巧：深入探讨数据存储方法

//点击按钮1，使用MODE_PRIVATE模式，生成一个私有的文件
public void click1(View v){
try {
FileOutputStream fos = openFileOutput("private.txt", MODE_PRIVATE);
fos.write("private".getBytes());
fos.close();
} catch (Exception e) {
e.printStackTrace();
}
}

//点击按钮2，使用MODE_PRIVATE模式，生成一个appent文件
public void click2(View v){
try {
FileOutputStream fos = openFileOutput("appent.txt", MODE_PRIVATE);
fos.write("appent".getBytes());
fos.close();
} catch (Exception e) {
e.printStackTrace();
}
}

//点击按钮3，使用MODE_WORLD_READABLE模式，生成一个readable文件
public void click3(View v){
try {
FileOutputStream fos = openFileOutput("readable.txt", MODE_WORLD_READABLE);
fos.write("readable".getBytes());
fos.close();
} catch (Exception e) {
e.printStackTrace();
}
}

//点击按钮4，使用MODE_WORLD_WRITEABLE模式，生成一个write文件
public void click4(View v){
try {
FileOutputStream fos = openFileOutput("writeable.txt", MODE_WORLD_WRITEABLE);
fos.write("writeable".getBytes());
fos.close();
} catch (Exception e) {
e.printStackTrace();
}
}

try {
//File file = new File("/data/data/com.test.filereadwrite/files/readable.txt");
File file = new File("/data/data/com.test.filereadwrite/files/writeable.txt");
FileInputStream fis = new FileInputStream(file);
BufferedReader bffr = new BufferedReader(new InputStreamReader(fis));
String content = bffr.readLine();
Toast.makeText(MainActivity.this, content, 2000).show();
} catch (Exception e) {
e.printStackTrace();
}

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

//初始化我们要备份的数据
smsLists = new ArrayList();

//插入测试数据
for (int i = 0; i <10; i++) {
Sms sms = new Sms();
sms.setAddress("10086"+i);
sms.setBody("你好"+i);
sms.setDate("201"+i);
//把sms对象加入到集合中
smsLists.add(sms);
}
}

//点击按钮button1，通过StringBuffer的方式生成一个xml文件
public void click1(View v){
//1创建一个StringBuffer对象
StringBuffer sb = new StringBuffer();

//开始组拼xml文件头
sb.append("");
//开始组拼xml根节点
sb.append("");
//开始组拼sms节点以及子节点
for (Sms sms : smsLists) {
sb.append("");

//组拼addressa节点
sb.append("

//点击按钮button2，通过XmlSerializer的方式生成xml文件
public void click2(View v){
try {
//获取XmlSerializer类的实例 通过xml这个工具类去获取
XmlSerializer serializer = Xml.newSerializer();
//设置XmlSerializer序列化参数
File file = new File(Environment.getExternalStorageDirectory().getPath(),"smsbackup.xml");
FileOutputStream fos = new FileOutputStream(file);
serializer.setOutput(fos,"utf-8");
//开始写xml文档开头
serializer.startDocument("utf-8", true);
//写xml的根节点 namespace 命名空间
serializer.startTag(null, "smss");
//遍历sms节点以及子节点
for (Sms sms : smsLists) {
serializer.startTag(null, "sms");

//组拼addressa节点
serializer.startTag(null, "address");
serializer.text(sms.getAddress());
serializer.endTag(null, "address");

//组拼body节点
serializer.startTag(null, "body");
serializer.text(sms.getBody());
serializer.endTag(null, "body");

//组拼date节点
serializer.startTag(null, "date");
serializer.text(sms.getDate());
serializer.endTag(null, "date");

serializer.endTag(null, "sms");
}
serializer.endTag(null, "smss");

//結束xml結尾
serializer.endDocument();
//关闭流
fos.close();

} catch (Exception e) {
e.printStackTrace();
}
}

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

try {
//显示数据信息
TextView tv_sms = (TextView) findViewById(R.id.tv_weather);
//通过上下文 获取资产的管理者
InputStream in = getAssets().open("smss.xml");
//调用我们定义 解析xml的业务方法
List smsLists = SmsParser.xmlParser(in);

StringBuffer sb = new StringBuffer();
for (Sms sms : smsLists) {
sb.append(sms.toString());
}

//把数据显示到TextView上
tv_sms.setText(sb.toString());

} catch (Exception e) {
e.printStackTrace();
}
}