Andriod——数据存储 SharedPrefrences

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">
<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"
        android:orientation="horizontal">
        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:text="保存"
            android:layout_weight="1"
            android:onClick="baocunonclick"/>
        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:text="获取"
            android:layout_weight="1"
            android:onClick="huoquonclick"/>

    </LinearLayout>
</LinearLayout>

java

package com.example.chenshuai.test321;

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 Activitydata extends AppCompatActivity {

    EditText et_1;
    EditText et_2;
    SharedPreferences sp;//不能通过set方法存，通过edit存数据
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_activitydata);

        et_1 = (EditText)findViewById(R.id.et_1);
        et_2 = (EditText)findViewById(R.id.et_2);

        //1.获取SP的实例，指定了文件名和操作模式
        sp = getSharedPreferences("mydata",MODE_PRIVATE);
    }

    //保存
    public void baocunonclick(View view)
    {
        //1.获取key和value
        String key = et_1.getText().toString();
        String value = et_2.getText().toString();

        if (key.length()==0 || value.length()==0)
        {
            Toast.makeText(Activitydata.this, "key或value不为空", Toast.LENGTH_SHORT).show();
        }

        else {
            //2.获取Editor
            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(Activitydata.this, "保存成功", Toast.LENGTH_SHORT).show();
            } else {
                Toast.makeText(Activitydata.this, "失败", Toast.LENGTH_SHORT).show();
            }
        }
    }

    //获取
    public void huoquonclick(View view)
    {
        //1.获取要读的key
        String key = et_1.getText().toString();

        //2.读并设置文本框
        et_2.setText(sp.getString(key,"没有发现key"));

    }
}