Android存储之SharedPreferences

标签：android   sharedpreferences   存储   

<?xml version="1.0" encoding="utf-8"?>
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:stretchColumns="1"
    >
    <TableRow>
        <TextView
            android:gravity="right"
            android:textStyle="bold"
            android:padding="3dip"
            android:text="用户名称："
        />

        <EditText
            android:id="@+id/username"
            android:inputType="text"
            android:padding="3dip"
            android:scrollHorizontally="true" />

    </TableRow>
    <TableRow>
        <TextView
            android:gravity="right"
            android:textStyle="bold"
            android:padding="3dip"
            android:text="用户密码："
        />

        <EditText
            android:id="@+id/password"
            android:inputType="textPassword"
            android:padding="3dip" />

    </TableRow>
    <TableRow android:gravity="right">
        <Button
            android:id="@+id/cancel"
            android:text="取消" 
        />
        <Button
            android:id="@+id/login"
            android:text="登录" 
        />
    </TableRow>
</TableLayout>

package com.rainsong.sharedpreferencesdemo;

import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {
    private static final String PREFERENCES_NAME = "sharedpreferencesdemo";
    private static final String KEY_USERNAME = "username";
    private static final String KEY_PASSWORD = "password";

    Button btn_login;
    Button btn_cancel;
    EditText et_username;
    EditText et_password;

    OnClickListener listener_login;
    OnClickListener listener_cancel;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        et_username = (EditText) findViewById(R.id.username);
        et_password = (EditText) findViewById(R.id.password);

        listener_login = new OnClickListener() {
            public void onClick(View v) {
                String username;
                String password;
                username = et_username.getText().toString();
                if (username.length() < 1) {
                    Toast.makeText(MainActivity.this, "请输入用户名",
                            Toast.LENGTH_LONG).show();
                    return;
                }
                password = et_password.getText().toString();
                if (password.length() < 1) {
                    Toast.makeText(MainActivity.this, "请输入密码",
                            Toast.LENGTH_LONG).show();
                    return;
                }

                SharedPreferences pref = getSharedPreferences(PREFERENCES_NAME, Context.MODE_APPEND);
                Editor edit = pref.edit();
                edit.putString(KEY_USERNAME, username);
                edit.putString(KEY_PASSWORD, password);
                edit.commit();
                Toast.makeText(MainActivity.this, "用户名称：" + username
                    + ", 用户密码：" + password,Toast.LENGTH_SHORT).show();
            }
        };
        
        btn_login = (Button)findViewById(R.id.login);
        btn_login.setOnClickListener(listener_login);
        
        listener_cancel = new OnClickListener() {
            public void onClick(View v) {
                SharedPreferences pref = getSharedPreferences(PREFERENCES_NAME, Context.MODE_APPEND);
                Editor edit = pref.edit();
                edit.clear();
                edit.commit();
                et_username.setText("");
                et_password.setText("");
            }
        };
        
        btn_cancel = (Button)findViewById(R.id.cancel);
        btn_cancel.setOnClickListener(listener_cancel);

        SharedPreferences pref = getSharedPreferences(PREFERENCES_NAME, Context.MODE_APPEND);
        String username;
        String password;
        username = pref.getString(KEY_USERNAME, "");
        password = pref.getString(KEY_PASSWORD, "");
        et_username.setText(username);
        et_password.setText(password);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

}

通过上述代码可以看到，在onCreate中使用findViewById得到两个EditText后，使用getSharedPreferences()方法取得SharedPreferences对象，然后使用getString()方法取得其中保存的值，最后使用setText()方法将其值设置为两个EditText的值。

在单击“登录”按钮时，首先使用getSharedPreferences()方法取得SharedPreferences对象；然后调用edit()方法使其处于可编辑状态，并使用putString()方法将两个EditText中的值保存起来；最后使用commit()方法提交即可保存。

Set a String value in the preferences editor, to be written back once commit() or apply() are called.

Android存储之SharedPreferences

标签：android   sharedpreferences   存储   

原文地址：http://blog.csdn.net/hantangsongming/article/details/42079899