sharepreferences

1,sharepreferences在程序中创建一个xml

SharedPreferences myshareperferemces=getSharedPreferences("yuhan", Activity.MODE_PRIVATE);

//创建一个yuhan的xml，如果存在则直接引用，存在data->data->projactname->share_prefs中xml,模式加密本程序才能访问

SharedPreferences.Editor editor=myshareperferemces.edit();

//开始编辑xml

//put里边的值如果不存在，则创建，并且给一个默认值

editor.putBoolean("issuccessed", true);

editor.putFloat("float", (float) 1.5);

editor.putInt("int", 1);

editor.putLong("long", 1);

editor.putString("string", "string");

editor.apply();

//异步线程更新

boolean isyes=myshareperferemces.getBoolean("issuccessed", false);

int number=myshareperferemces.getInt("int", 0);

//从yuhan.xml中拿到对应的值，如果不存在，则得到默认值

Map<String,?> allPreferences=myshareperferemces.getAll();

Boolean containlastfloat=allPreferences.containsKey("lastfloat");

产生的yuhan.xml

<?xml version="1.0" encoding="UTF-8" standalone="true"?>

<map>

<boolean value="true" name="issuccessed"/>

<long value="1" name="long"/>

<float value="1.5" name="float"/>

<int value="1" name="int"/>

<string name="string">string</string>

</map>


2,

package com.example.hello;

import java.util.Map;

import android.app.Activity;

import android.content.Context;

import android.content.SharedPreferences;

import android.content.SharedPreferences.Editor;

import android.os.Bundle;

import android.preference.PreferenceManager;

import android.support.v7.appcompat.R.dimen;

import android.util.Log;

import android.view.View;

import android.widget.ArrayAdapter;

import android.widget.Button;

import android.widget.CheckBox;

import android.widget.Spinner;

public class MainActivity extends Activity {

CheckBox autoUpdate;//是否自动更新

Spinner updateFreSpinner;//更新频率

Spinner magnitudeSpinner;//更新时间间隔

SharedPreferences prefs;//得到sharepreferences

public static final String USER_PREFERENCE="USER_PREFERENCE";

public static final String PREF_AUTO_UPDATE="PREF_AUTO_UPDATE";

public static final String PREF_MIN_MAG_INDEX="PREF_MIN_MAG_INDEX";

public static final String PREF_UPDATE_FREQ_INDEX="PREF_UPDATE_FREQ_INDEX";

//这种写法将非常常用，应该要养成习惯，代表值应该要写在程序的上方，或者单独要一个文件夹来写

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.preferences);

updateFreSpinner=(Spinner) findViewById(R.id.spinner_update_freq);

magnitudeSpinner=(Spinner) findViewById(R.id.spinner_quake_mag);

autoUpdate=(CheckBox) findViewById(R.id.checkbox);

//初始化控件

populateSpinners();//将值放到下拉控件上

Context context=getApplicationContext();//得到当前context

prefs=PreferenceManager.getDefaultSharedPreferences(context);//得到context默认的sharepreferences

updateUIFromPreferences();

//初始化context中的键值对，并把defaultsharepreferences的值给spinner，等待以后选择，更新

Button okButton=(Button) findViewById(R.id.okButton);

//点击ok按钮，defaultsharepreferences就要更新键值对了

okButton.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

// TODO Auto-generated method stub

savePreferences();//点击了ok，键值对的值要更新了

finish();

}

private void savePreferences() {

// TODO Auto-generated method stub

int updateIndex=updateFreSpinner.getSelectedItemPosition();

int minMagIndex=magnitudeSpinner.getSelectedItemPosition();

Boolean autoUpdateChecked=autoUpdate.isChecked();

Editor editor=prefs.edit();

editor.putBoolean(PREF_AUTO_UPDATE, autoUpdateChecked);

editor.putInt(PREF_UPDATE_FREQ_INDEX, updateIndex);

editor.putInt(PREF_MIN_MAG_INDEX, minMagIndex);

editor.commit();

}

});

}

private void updateUIFromPreferences() {

// TODO Auto-generated method stub

Boolean autoUpChecked=prefs.getBoolean(PREF_AUTO_UPDATE, false);

int updateFreqIndex=prefs.getInt(PREF_UPDATE_FREQ_INDEX, 2);

updateFreSpinner.setSelection(updateFreqIndex);

autoUpdate.setChecked(autoUpChecked);

}

private void populateSpinners() {

// TODO Auto-generated method stub

ArrayAdapter<CharSequence> fAdapter;

fAdapter=ArrayAdapter.createFromResource(this, R.array.update_freq_options, android.R.layout.simple_spinner_item);

int spinner_dd_item=android.R.layout.simple_spinner_dropdown_item;

fAdapter.setDropDownViewResource(spinner_dd_item);

updateFreSpinner.setAdapter(fAdapter);

ArrayAdapter<CharSequence> mAdapter;

mAdapter=ArrayAdapter.createFromResource(this, R.array.magnitude_options, android.R.layout.simple_spinner_item);

mAdapter.setDropDownViewResource(spinner_dd_item);

magnitudeSpinner.setAdapter(mAdapter);

}

}

arrays.xml

<?xml version="1.0" encoding="utf-8"?>

<resources>

<string-array name="update_freq_options">

<item >Every Minute</item>

<item >5 minutes</item>

<item >10 minutes</item>

<item >15 minutes</item>

<item >Every Hour</item>

</string-array>

<string-array name="magnitude">

<item >3</item>

<item >5</item>

<item >6</item>

<item >7</item>

<item >8</item>

</string-array>

<string-array name="magnitude_options">

<item >3</item>

<item >5</item>

<item >6</item>

<item >7</item>

<item >8</item>

</string-array>

<string-array name="update_freq_values">

<item >1</item>

<item >5</item>

<item >10</item>

<item >15</item>

<item >60</item>

</string-array>

</resources>

string.xml

<?xml version="1.0" encoding="utf-8"?>

<resources>

<string name="app_name">hello</string>

<string name="hello_world">Hello world!</string>

<string name="action_settings">Settings</string>

<string name="menu_update"> Refresh Earthquakes</string>

<string name="auto_update_prompt">Auto Update?</string>

<string name="update_freq_prompt">Update Frequency</string>

<string name="min_quake_mag_prompt">Minimun Quake Magnitude</string>

<string name="menu_preferences">Preferences</string>

</resources>

preferences.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical" >

<TextView

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="@string/auto_update_prompt"/>

<CheckBox

android:id="@+id/ckeckbox_auto_update"

android:layout_width="fill_parent"

android:layout_height="wrap_content"/>

<TextView

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="@string/update_freq_prompt"/>

<Spinner

android:id="@+id/spinner_update_freq"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:drawSelectorOnTop="true"/>

<TextView

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="@string/min_quake_mag_prompt"/>

<Spinner

android:id="@+id/spinner_quake_mag"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:drawSelectorOnTop="true"/>

<LinearLayout

android:orientation="horizontal"

android:layout_width="fill_parent"

android:layout_height="wrap_content">

<Button

android:id="@+id/okButton"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="@android:string/ok"/>

<Button

android:id="@+id/cannelButton"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="@android:string/cancel"/>

</LinearLayout>

</LinearLayout>