Android数据存储之XmlPull解析XML文件(输出部分)

为了逻辑更清晰，输出部分单独新建一个项目：XmlPullWriteProject

还是先写XmlPullUtll操作类：

构造方法与基本的成员变量：

public class XmlPullUtil {
    
    // 需要两个参数:一个输出流和一个节点对象列表
    private OutputStream outputStream = null;
    private List<Person> persons = null;
    
    private XmlPullParserFactory xppFac = null;
    private XmlSerializer xs = null; // 输出操作使用XmlSerializer类
    
    public XmlPullUtil(OutputStream outputStream, List<Person> persons) {
        this.outputStream = outputStream;
        this.persons = persons;
    }

负责生成Xml的方法：

public void generateXml() throws XmlPullParserException, IOException{
        xppFac = XmlPullParserFactory.newInstance();
        xs = xppFac.newSerializer();
        // 设置输出流与编码
        xs.setOutput(outputStream, "UTF-8");
        
        // 下面的步骤很好理解，按照xml的格式放入各个元素
        xs.startDocument("UTF-8", true);
        xs.startTag(null, "moka");
        Iterator<Person> it = persons.iterator();
        while (it.hasNext()) {
            Person person = it.next();
            xs.startTag(null, "person");
            xs.startTag(null, "id");
            xs.text(person.getId());
            xs.endTag(null, "id");
            xs.startTag(null, "name");
            xs.text(person.getName());
            xs.endTag(null, "name");
            xs.endTag(null, "person");
        }
        xs.endTag(null, "moka");
        xs.endDocument();
        // 将所有准备的数据放入输出流
        xs.flush();
    }
    
}

主Activity:

检测储存环境方法与读取篇相同，这里不再写出

public class MainActivity extends Activity {
    
    private EditText idText = null;
    private EditText nameText = null;
    private Button saveBtn = null;
    private File file = null; 
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        idText = (EditText) findViewById(R.id.idText);
        nameText = (EditText) findViewById(R.id.nameText);
        saveBtn = (Button) findViewById(R.id.saveBtn);
        
        saveBtn.setOnClickListener(new SaveBtnListener());
    }
    
    private class SaveBtnListener implements OnClickListener {

        @Override
        public void onClick(View v) {
            // 首先调用检测储存环境的方法
            if(!MainActivity.this.CheckEnvironment()) {
                return;
            } else {
                generateElements();
            }
        }
        
    }

generateElements():

    private void generateElements() {
        // 创建欲添加的节点对象列表
        List<Person> persons = new ArrayList<Person>();
        for (int i = 0; i < 3; i++) {
            Person person = new Person();
            person.setId("" + i);
            person.setName("shuai " + i);
            persons.add(person);
        }
        
        // 实例化XmlPull操作类，调用生成xml文件方法
        try {
            XmlPullUtil xpu = new XmlPullUtil(new FileOutputStream(file), persons);
            xpu.generateXml();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (XmlPullParserException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    
}

生成文档如下：