android学习笔记（1）

09：布局

LineaerLayout(线性布局)、RelativeLayout(相对布局)：android:layout_toRightOf,android:layout_alignTop

TableLayout(表格布局)、FrameLayout(帧布局)

常用RelativeLayout(相对布局)、TableLayout(表格布局)

10：测试

在应用配置文件导测试依赖包

<uses-library android:name="android.test.runner" />

<instrumentation android:name="android.test.InstrumentationTestRunner"

android:targetPackage="cn.itcast.test" android:label="Tests for My App" />

12：文件读写

应用内文件的保存读取

context.openFileOutput(filename, Context.MODE_PRIVATE);//保存

context.openFileInput(filename);//读取

13：文件模式

4种模式

Context.MODE_PRIVATE 覆盖写，私有

Context.MODE_APPEND 追加写，私有

Context.MODE_WORLD_WRITEABLE 可写

Context.MODE_WORLD_READABLE 可读

Context.MODE_WORLD_READABLE+Context.MODE_WORLD_WRITEABLE 可读写

14：SD卡文件读写

//获取SDCard路径

Environment.getExternalStorageDirectory();

//判断SDCard是否存在，并且可以读写

if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){}

15：pull解析器解析XML

//读取XML

XmlPullParser pullParser=Xml.newPullParser();

pullParser.setInput(inputStream,"UTF-8");

int event = pullParser.getEventType();

while(event != XmlPullParser.END_DOCUMENT){

switch (event) {

case XmlPullParser.START_DOCUMENT:

persons = new ArrayList<Person>();

break;

case XmlPullParser.START_TAG:

if("person".equals(pullParser.getName())){

int id = new Integer(pullParser.getAttributeValue(0));

person = new Person();

person.setId(id);

}

if("name".equals(pullParser.getName())){

String name = pullParser.nextText();

person.setName(name);

}

if("age".equals(pullParser.getName())){

int age = new Integer(pullParser.nextText());

person.setAge(age);

}

break;

case XmlPullParser.END_TAG:

if("person".equals(pullParser.getName())){

persons.add(person);

person = null;

}

break;

}

event = pullParser.next();

}

//写XML

XmlSerializer serializer = Xml.newSerializer();

serializer.setOutput(out, "UTF-8");

serializer.startDocument("UTF-8", true);

serializer.startTag(null, "persons");

for(Person person : persons){

serializer.startTag(null, "person");

serializer.attribute(null, "id", person.getId().toString());

serializer.startTag(null, "name");

serializer.text(person.getName());

serializer.endTag(null, "name");

serializer.startTag(null, "age");

serializer.text(person.getAge().toString());

serializer.endTag(null, "age");

serializer.endTag(null, "person");

}

serializer.endTag(null, "persons");

serializer.endDocument();

out.flush();

out.close();

16.保存用户偏好设置参数

android:numeric="integer"//只能输入整型

android:onClick="save"//点击事件

save对应activity里的save方法

public void save(String name, Integer age) {

SharedPreferences preferences = context.getSharedPreferences("itcast", Context.MODE_PRIVATE);

Editor editor = preferences.edit();

editor.putString("name", name);

editor.putInt("age", age);

editor.commit();

}

/**

* 获取各项配置参数

* @return

*/

public Map<String, String> getPreferences(){

Map<String, String> params = new HashMap<String, String>();

SharedPreferences preferences = context.getSharedPreferences("itcast", Context.MODE_PRIVATE);

params.put("name", preferences.getString("name", ""));

params.put("age", String.valueOf(preferences.getInt("age", 0)));

return params;

}