andorid 数据储存

.xml

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

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

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:paddingBottom="@dimen/activity_vertical_margin"

    android:paddingLeft="@dimen/activity_horizontal_margin"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    tools:context="com.hanqi.application3.DataActivity1"

    android:orientation="vertical">

    <EditText

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:id="@+id/et_1"

        android:hint="Key"/>

    <EditText

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:id="@+id/et_2"

        android:hint="Value"/>

    <LinearLayout

        android:layout_width="match_parent"

        android:layout_height="wrap_content">

        <Button

            android:layout_width="0dp"

            android:layout_height="wrap_content"

            android:text="保存"

            android:layout_weight="1"

            android:onClick="bt1_onClick"/>

        <Button

            android:layout_width="0dp"

            android:layout_height="wrap_content"

            android:text="读取"

            android:layout_weight="1"

            android:onClick="bt2_onClick"/>

    </LinearLayout>

</LinearLayout>

.java

package com.hanqi.application3;

import android.content.SharedPreferences;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.View;

import android.widget.EditText;

import android.widget.Toast;

public class DataActivity1 extends AppCompatActivity {

    EditText et1;

    EditText et2;

    SharedPreferences sp;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_data1);

        et1=(EditText)findViewById(R.id.et_1);

        et2=(EditText)findViewById(R.id.et_2);

        //1.获取sp的实例，制定了文件名和操作模式

        sp = getSharedPreferences("mydata",MODE_PRIVATE);

    }

    //保存

    public void bt1_onClick(View v)

    {

        //1.获取Key和Value

        String key = et1.getText().toString();

        String value = et2.getText().toString();

        if (key.length() ==0||value.length() == 0)

        {

            Toast.makeText(DataActivity1.this, "key或value不能为空", Toast.LENGTH_SHORT).show();

        }

        else {

        //2.取得Editor        edit编辑器

        SharedPreferences.Editor editor = sp.edit();

        //3.放入键值对

        editor.putString(key,value);

        //4.提交保存

        boolean b = editor.commit();

        if (b)

        {

            Toast.makeText(DataActivity1.this, "保存成功", Toast.LENGTH_SHORT).show();

        }

        else

        {

            Toast.makeText(DataActivity1.this, "保存失败", Toast.LENGTH_SHORT).show();

        }

        }

    }

    //读取

    public void bt2_onClick(View v)

    {

        //1.获取要读的key

        String key = et1.getText().toString();

        //2.读并设置文本框

        et2.setText(sp.getString(key,"没有发现key"));

    }

}