目录
安卓应用
一、调用打电话接口
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void sendReceiver(View view) {
EditText et = findViewById(R.id.et);
String phoneNumber = et.getText().toString().trim();
if ("".equals(phoneNumber)) {
// context:如果是在当前类就是this，如果是在内部类则是当前类.this
Toast.makeText(this, "电话号码不能为空", Toast.LENGTH_SHORT).show();
} else {
// 调用打电话接口需要用户开放打电话权限
// <uses-permission android:name="android.permission.CALL_PHONE" />
Intent intent = new Intent();// 意图
intent.setAction(Intent.ACTION_CALL);
intent.setData(Uri.parse("tel:" + phoneNumber));
startActivity(intent);
}
}
}
二、内部存储读写数据
public class UserInfoUtils {
public static boolean saveInfo(Context context, String username, String password) {
try {
// /data/data/包名/files/
/**
* 参数2：Context.MODE_PRIVATE：私有；
* Context.MODE_APPEND：追加；
* Context.MODE_WORLD_READABLE：其他应用可读；
* Context.MODE_WORLD_WRITEABLE：其他应用可写；
*/
FileOutputStream fos = context.openFileOutput("info.txt", 0);
String result = username + "##" + password;
fos.write(result.getBytes());
fos.close();
return true;
} catch (IOException e) {
e.printStackTrace();
return false;
}
}
public static Map<String, String> readInfo(Context context) {
try {
FileInputStream fis = context.openFileInput("info.txt");
BufferedReader bufr = new BufferedReader(new InputStreamReader(fis));
String content = bufr.readLine();
String[] strings = content.split("##");
HashMap<String, String> map = new HashMap<>();
map.put("username", strings[0]);
map.put("password", strings[1]);
fis.close();
return map;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
}
三、外部存储读写数据
- 添加权限
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
- 获取sd卡信息
// 判断sd卡状态是否可用
if (Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {
Toast.makeText(this, "sd卡可用", Toast.LENGTH_SHORT).show();
// 获取sd卡总大小和可用空间
File sdcard = Environment.getExternalStorageDirectory();
System.out.println("sd卡总大小：" + Formatter.formatFileSize(this, sdcard.getTotalSpace()));
System.out.println("可用空间：" + Formatter.formatFileSize(this, sdcard.getUsableSpace()));
}
- 获取sd卡目录
// 外部存储目录：/mnt/sdcard/
String path = Environment.getExternalStorageDirectory().getPath();
File file = new File(path, "info.txt");
FileOutputStream fos = new FileOutputStream(file);
四、SharedPreferences存储数据
- 存
// 写入的目录：/data/data/com.wuxi.myandroid/shared_prefs
SharedPreferences sp = getSharedPreferences("info", 0);
SharedPreferences.Editor edit = sp.edit();
edit.putString("uname", uname);
edit.putString("pword", pword);
edit.apply();
- 取
SharedPreferences sp = getSharedPreferences("info", 0);
// 参数2：未取到值时返回的值
String uname = sp.getString("uname", "");
String pword = sp.getString("pword", "");
五、XmlSerializer生成xml文件
public void generateXml(View view) {
try {
XmlSerializer xml = Xml.newSerializer();
String path = Environment.getExternalStorageDirectory().getPath();
File file = new File(path, "info.xml");
FileOutputStream fos = new FileOutputStream(file);
xml.setOutput(fos, "utf-8");
// 头文件属性
xml.startDocument("utf-8", true);
// 节点
xml.startTag(null, "div");
xml.text("这是一段中文");
xml.endTag(null, "div");
xml.endDocument();
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
六、XmlPullParser解析xml文件
- xml放在/src/main/assets目录下，没有则新建该目录
- MainActivity
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextView tv = findViewById(R.id.tv);
try {
// 获取assets目录
InputStream is = getAssets().open("person.xml");
List<Person> persons = PullParserXmlUtil.parserXml(is);
StringBuffer sb = new StringBuffer();
for (Person person : persons) {
sb.append(person.toString());
}
tv.setText(sb);
} catch (Exception e) {
e.printStackTrace();
}
}
}
- PullParserXmlUtil
public class PullParserXmlUtil {
public static List<Person> parserXml(InputStream xml) throws Exception {
List<Person> persons = null;
Person person = null;
// 获取解析实例
XmlPullParser parser = Xml.newPullParser();
parser.setInput(xml, "utf-8");
// 获得事件的类型
int eventType = parser.getEventType();
while (eventType != XmlPullParser.END_DOCUMENT) {
switch (eventType) {
case XmlPullParser.START_DOCUMENT:
persons = new ArrayList<Person>();
break;
case XmlPullParser.START_TAG:
if ("person".equals(parser.getName())) {
person = new Person();
// 取出属性值
int id = Integer.parseInt(parser.getAttributeValue(0));
person.setId(id);
} else if ("name".equals(parser.getName())) {
String name = parser.nextText();// 获取该节点的内容
person.setName(name);
} else if ("age".equals(parser.getName())) {
int age = Integer.parseInt(parser.nextText());
person.setAge(age);
}
break;
case XmlPullParser.END_TAG:
if ("person".equals(parser.getName())) {
persons.add(person);
person = null;
}
break;
}
eventType = parser.next();
}
return persons;
}
}
