private final class SaveButtonClickListener implements View.OnClickListener {
@Override
public void onClick(View v) {
EditText fileName = (EditText) findViewById(R.id.fileName);
EditText fileContent = (EditText) findViewById(R.id.fileContent);
String fileNameStr = fileName.getText().toString();
String fileContentStr = fileContent.getText().toString();
FilesService fileSer = new FilesService(getApplicationContext());
try {
fileSer.save(fileNameStr,fileContentStr);
Toast.makeText(getApplicationContext(),R.string.saveSuccess,2)
.show();
} catch (Exception e) {
Toast.makeText(getApplicationContext(),R.string.saveFaile,2)
.show();
}
}
文件操作 String path = "/data/data/com.yza.app/files/t.txt"; “t.txt” 与fileNameStr 一样
getFilesDir() 获取当前应用files目录
getCacheDir() 获取当前应用cache目录
public class FilesService {
private Context context;
public FilesService(Context context) {
super();
this.context = context;
}
public void save(String fileNameStr,String fileContentStr)
throws Exception {
// 操作模式 MODE_PRIVATE 只能被本应用使用,且覆盖原内容
FileOutputStream fos = context.openFileOutput(fileNameStr,Context.MODE_PRIVATE);
fos.write(fileContentStr.getBytes());
fos.close();
}
public String read(String fileNameStr) throws Exception {
FileInputStream fis = context.openFileInput(fileNameStr);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int len = 0;
while ((len = fis.read(buffer)) != -1) {
baos.write(buffer,len);
}
return new String(baos.toByteArray());
}
}
操作模式 MODE_PRIVATE 只能被本应用使用,且覆盖原内容
1.Context.MODE_PRIVATE = 0;//私有的，只能被创建这个文件的当前应用访问，若创建的文件已经存在，则会覆盖掉原来的文件
2.Context.MODE_APPEND = 32768;//若文件不存在也会创建，若文件存在则在文件的末尾进行追加内容，也是私有的
3.Context.MODE_WORLD_READABLE=1;//创建出来的文件可以被其他应用所读取
4.Context.MODE_WORLD_WRITEABLE=2//允许其他应用对其进行写入。
当然，这几种模式也可以混用，比如允许其他应用程序对该文件进行读写，则可以是
FileOutputStream outStream = this.openFileOutput("itcast.txt",Context.MODE_WORLD_READABLE+Context.MODE_WORLD_WRITEABLE);
该方式默认为覆盖原有的文件，即如果再次对该文件写入内容，则会覆盖掉itcast.txt的原有内容，如果想要实现追加并能被其他应用程序访问，则应该设置以下模式：
FileOutputStream outStream = this.openFileOutput("itcast.txt",Context.MODE_APPEND+Context.MODE_WORLD_READABLE+Context.MODE_WORLD_WRITEABLE);
文件保存到SDCard：
public void savetoSDCard(String fileName,String content)throws Exception{ File file = new File(new File("/mnt/sdcard"),fileName); FileOutputStream fos = new FileOutputStream(file); fos.write(content.getBytes()); fos.close(); }
推荐使用API的路径： File file = new File(Environment.getExternalStorageDirectory(),fileName);
<!-- sdcard 创建与删除的权限 -->
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYstemS"/>
<!-- sdcard 存储权限 -->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
XML解析
解析的核心代码
public class PersonService {
public static List<Person> getPersonList(InputStream xml) throws Exception {
List<Person> plist = null;
Person p = null;
XmlPullParser pullParser = Xml.newPullParser();
pullParser.setInput(xml,"UTF-8");// 设置要解析的XMl数据
int event = pullParser.getEventType();
Log.i("person","进入解析");
while (event != XmlPullParser.END_DOCUMENT) {
switch (event) {
case XmlPullParser.START_DOCUMENT:
plist = new ArrayList<Person>();
break;
case XmlPullParser.START_TAG:
if ("person".equals(pullParser.getName())) {
p = new Person();
p.setId(Integer.parseInt(pullParser.getAttributeValue(0)));
}
if ("name".equals(pullParser.getName())) {
p.setName(pullParser.nextText());
}
if ("age".equals(pullParser.getName())) {
p.setAge(Integer.parseInt(pullParser.nextText()));
}
break;
case XmlPullParser.END_TAG:
if ("person".equals(pullParser.getName())) {
plist.add(p);
p = null;
}
break;
}
event = pullParser.next();
}
return plist;
}
}
<?xml version="1.0" encoding="UTF-8"?> <persons> <person id="22"> <name>zhangsan</name> <age>20</age> </person> <person id="24"> <name>lisi</name> <age>15</age> </person> </persons>
public void testA() throws Exception {
Log.i("person","PersonService");
InputStream xml = this.getClass().getClassLoader()
.getResourceAsstream("person.xml");
Log.i("person","12"+(xml==null));
List<Person> l = PersonService.getPersonList(xml);
for (Person p : l) {
Log.i("person",p.getName());
}
}
保存
public void saveXML(List<Person> list,OutputStream out) throws Exception {
XmlSerializer xs = Xml.newSerializer();
xs.setoutput(out,"UTF-8");
xs.startDocument("UTF-8",true);
xs.startTag(null,"persons"); //不需要命名空间
for (Person p : list) {
xs.startTag(null,"person");
xs.attribute(null,"id",p.getId().toString());
xs.startTag(null,"name");
xs.text(p.getName());
xs.endTag(null,"name");
xs.startTag(null,"age");
xs.text(p.getAge().toString());
xs.endTag(null,"age");
xs.endTag(null,"person");
}
xs.endTag(null,"persons");
xs.endDocument();
out.flush();
out.close();
}
SharedPreferences
public class Shareprefaractivity extends Activity { private EditText name; private EditText age; private PreferencesService ps; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); name = (EditText) this.findViewById(R.id.nameText); age = (EditText) this.findViewById(R.id.ageText); ps= new PreferencesService(getApplicationContext()); Map<String,String> map =ps.read(); name.setText(map.get("name")); age.setText(map.get("age")); } public void save(View v){ System.out.println(ps==null); System.out.println(age.getText().toString()); System.out.println(age.getText().toString()); ps.save(name.getText().toString(),Integer.valueOf(age.getText().toString())); Toast.makeText (getApplicationContext(),"成功保存",1).show(); } }
public class PreferencesService {
private Context context;
public PreferencesService(Context context) {
this.context = context;
}
public void save(String name,Integer age) {
SharedPreferences pre = context.getSharedPreferences("yza",Context.MODE_PRIVATE);// 默认后缀xml yza.xml
Editor edit = pre.edit();
edit.putString("name",name);
edit.putInt("age",age);
edit.commit();
}
// 获取参数
public Map<String,String> read() {
Map<String,String> map = new HashMap<String,String>();
SharedPreferences pre = context.getSharedPreferences("yza",Context.MODE_PRIVATE);// 默认后缀xml yza.xml
map.put("name",pre.getString("name",""));
map.put("age",String.valueOf(pre.getInt("age",0)));
return map;
}
}
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