[Android UI 教學(7)] 記憶上次執行結果

1. 在紅色方塊處按下mouse右鍵，選擇source再選擇Override/Implement Methods


2.輸入程式

package com.example.sum;

import android.app.Activity;

import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;

import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class SumActivity extends Activity {
    /** Called when the activity is first created. */

 private String PREF_NUM1="NUM1";
 private String PREF_NUM2="NUM2";
 private String PREF_SUM="SUM";

 EditText et1, et2;
 Button bt;
 TextView tv;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        et1 = (EditText) findViewById(R.id.EditText01);
        et2 = (EditText) findViewById(R.id.EditText02);
        tv = (TextView) findViewById(R.id.TextView01);
        bt = (Button) findViewById(R.id.Button01);

        bt.setOnClickListener(new OnClickListener(){

   @Override
   public void onClick(View arg0) {
    // TODO Auto-generated method stub
    double d1,d2;
    d1 = Double.parseDouble(et1.getText().toString());
    d2 = Double.parseDouble(et2.getText().toString());
    tv.setText(Double.toString(d1+d2));
   }
         
        });
    }
 @Override
 protected void onPause() {
  // TODO Auto-generated method stub

  SharedPreferences pref = getSharedPreferences ("pref_apn" , MODE_PRIVATE);
      Editor ed = pref.edit();
  ed.putString(PREF_NUM1, et1.getText().toString());
  ed.putString(PREF_NUM2, et2.getText().toString());
  ed.putString(PREF_SUM, tv.getText().toString());
      ed.commit();
  
  super.onPause();
 }
 @Override
 protected void onResume() {
  // TODO Auto-generated method stub

  SharedPreferences pref = getSharedPreferences("pref_apn" , MODE_PRIVATE);
  et1.setText(pref.getString(PREF_NUM1, ""));
  et2.setText(pref.getString(PREF_NUM2, ""));
  tv.setText(pref.getString(PREF_SUM, ""));
  
  super.onResume();
 }
    
}

3. 在編輯框內輸入資料，然後離開程式，再執行程式，您會發現上次輸入狀態還在。