SharedPreferences(保存偏好参数)
初次接触SharedPreferences,借助code-pig的博客写的小demo。实现每次打开app自动填充上次推出时输入的名字和年龄。
工具类SharedService
package com.example.sharedpreference; import java.util.HashMap; import java.util.Map; import android.content.Context; import android.content.SharedPreferences; import android.content.SharedPreferences.Editor; import android.widget.Toast; public class SharedService { private Context context ; public SharedService(Context context) { // TODO Auto-generated constructor stub this.context = context ; } public void save(String name,String age) { SharedPreferences sp = context.getSharedPreferences("base", Context.MODE_WORLD_READABLE) ; Editor edit = sp.edit() ; edit.putString("name", name) ; edit.putString("age", age) ; edit.commit() ; Toast.makeText(context, "信息已经成功写入", Toast.LENGTH_LONG) ; } public Map<String,String> read() { Map<String,String> map = new HashMap<String, String>() ; SharedPreferences sp = context.getSharedPreferences("base", Context.MODE_WORLD_READABLE) ; map.put("name", sp.getString("name", "")) ; map.put("age", sp.getString("age", "")) ; return map ; } }
主activity
package com.example.sharedpreference; import android.support.v7.app.ActionBarActivity; import android.os.Bundle; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.EditText; public class MainActivity extends ActionBarActivity { private EditText name ; private EditText age ; private Button ok ; private SharedService ss ; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); this.name = (EditText) findViewById(R.id.name) ; this.age = (EditText)findViewById(R.id.age) ; this.ok = (Button) findViewById(R.id.ok) ; ss = new SharedService(this) ; this.name.setText(ss.read().get("name")); this.age.setText(ss.read().get("age")); this.ok.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub ss.save(name.getText().toString(), age.getText().toString()); } }); } }
布局代码:
<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:orientation="vertical" tools:context="com.example.sharedpreference.MainActivity" > <EditText android:id="@+id/name" android:layout_width="fill_parent" android:hint="输入姓名" android:layout_height="wrap_content"/> <EditText android:id="@+id/age" android:layout_width="fill_parent" android:layout_height="wrap_content" android:hint="输入年龄"/> <Button android:id="@+id/ok" android:layout_height="wrap_content" android:layout_width="fill_parent" android:text="确定"/> </LinearLayout>