Android应用开发揭秘之6.2 Android数据之SharePreference

注意图片中强调的那点。

使用SharePreference来存取数据，那么会在/data/data目录下产生一个文件夹shared_prefs，打开DDMS，在File Explorer标签

 

 

package lau.com;

 

import android.app.Activity;

import android.content.SharedPreferences;

import android.os.Bundle;

import android.view.KeyEvent;

import android.widget.TextView;

 

 

public class AndroidPractice extends Activity {

    /** Called when the activity is first created. */

 

       private SharedPreferences mSharedPreferences = null;

       boolean b;

       private TextView mTextView = null;

       public void onCreate(Bundle savedInstanceState) {

           super.onCreate(savedInstanceState);

           setContentView(R.layout.main);

           mSharedPreferences = getPreferences(Activity.MODE_PRIVATE);

           mTextView = (TextView)findViewById(R.id.tv);

          

           // 取得值，如果没有设置，那就使用默认值false

              b = mSharedPreferences.getBoolean("bool", false);

             

              if(b) {

                     mTextView.setText("true");

              } else {

                     mTextView.setText("false");

              }

       }

       @Override

       public boolean onKeyDown(int keyCode, KeyEvent event) {

              // TODO Auto-generated method stub

              if(keyCode == KeyEvent.KEYCODE_BACK) {

                     SharedPreferences uiState = getPreferences(0);

 

                     // 取得编辑对象

                     SharedPreferences.Editor editor = uiState.edit();

 

                     // 添加值

                     editor.putBoolean("bool", b);

                    

                     // 提交保存

                     editor.commit();

                    

                     this.finish();

                     return true;

              }

              return super.onKeyDown(keyCode, event);

       }

       @Override

       public boolean onKeyUp(int keyCode, KeyEvent event) {

              // TODO Auto-generated method stub

              switch(keyCode) {

              case KeyEvent.KEYCODE_DPAD_UP:

                     mTextView.setText("true");

                     b = true;

                     break;

              case KeyEvent.KEYCODE_DPAD_DOWN:

                     mTextView.setText("false");

                     b = false;

                     break;

              default:

                     break;

              }

              return super.onKeyUp(keyCode, event);

       }

}