Android应用开发揭秘之6.2 Android数据之FIles

可以知道，在默认情况下文件是不能在不同的程序间共享的。

同样，生成的文件在data/data中对应的目录下可以找到

 

package lau.com;

 

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.util.Properties;

 

import android.app.Activity;

import android.content.Context;

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);

          

           // 读取文件数据.

              load();

             

              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);

                    

                     //保存数据

                     save();

                    

                     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);

       }

      

      

       void load() {

              Properties properties = new Properties();

              try {

                     FileInputStream stream = this.openFileInput("settingfile.cfg");

                     properties.load(stream);

              } catch (FileNotFoundException e) {

                     // TODO: handle exception

                     return;

              } catch (IOException e) {

                     return;

              }

              b = Boolean.valueOf(properties.get("bool").toString());

       }

      

       boolean save() {

              Properties properties = new Properties();

              properties.put("bool", String.valueOf(b));

              try {

                     FileOutputStream stream = this.openFileOutput("settingfile.cfg", Context.MODE_WORLD_WRITEABLE);

                     properties.store(stream, "");

              } catch (FileNotFoundException e) {

                     // TODO: handle exception

                     return false;

              } catch (IOException e) {

                     return false;

              }

              return true;

       }

}