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1、使用 MD5 算法对 Android SQLite 中的内容进行加密，并显示加密效果 SQLitetestActivity java 代码package com.example.android;import java.math.BigInteger;import java.security.MessageDigest;import android.app.Activity;import android.content.ContentV alues;import android.content.Intent;import android.database.Cursor;import androi
2、d.os.Bundle;/import android.util.Log;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;public class SQLitetestActivity extends Activity private EditText et1,et2,et3;private Button button;private B
3、utton button2;private Button button3;myOpenHelper mhelper;/* Called when the activity is first created. */Overridepublic void onCreate(Bundle savedInstanceState) super.onCreate(savedInstanceState); setContentView(R.layout.main);mhelper=new myOpenHelper(getApplicationContext(); et1=(EditText)findView
4、 ById(R.id.name); et2=(EditText)findView ById(R.id.telephone); et3=(EditText)findView ById(R.id.email); button =(Button)findV iewById(R.id.button); button2=(Button)findView ById(R.id.button2); button3=(Button)findView ById(R.id.button3); button.setOnClickListener(new OnClickListener() public void on
5、Click(View v)String name =et1.getText().toString();String name1=MD5(name);String telephone =et2.getText().toString();String telephone1 =MD5(telephone);String email =et3.getText().toString();String email1 =MD5(email);ContentValues values=new ContentV alues(); values.put(name, name1);values.put(teleph
6、one, telephone1); values.put(email, email1);mhelper.insert(values);Intent intent=new Intent(SQLitetestActivity.this,QueryActivity.class); startActivity(intent););button2.setOnClickListener(new OnClickListener()public void onClick(View v)Cursor c=mhelper.query();for(int i=0;ic.getCount();i+)c.moveToP
7、osition(i); if(c.getString(1).equals(MD5(et1.getText().toString() Toast.makeText(SQLitetestActivity.this, c.getString(1)+n+c.getString(2)+n+c.getString(3), 2000).show(););button3.setOnClickListener(new OnClickListener()public void onClick(View v)String name =et1.getText().toString();String name1=MD5
8、(name);String telephone =et2.getText().toString();String telephone1 =MD5(telephone);String email =et3.getText().toString();String email1 =MD5(email);ContentValues values=new ContentV alues();values.put(name, name1); values.put(telephone, telephone1);values.put(email, email1); mhelper.update(values);
9、Intent intent=new Intent(SQLitetestActivity.this,QueryActivity.class); startActivity(intent););public static String MD5(String string) return encodeMD5String(string);public static String encodeMD5String(String str) return encode(str, MD5);private static String encode(String str, String method) Messa
10、geDigest md = null; String dstr = null;trymd = MessageDigest.getInstance(method);md.update(str.getBytes();dstr = new BigInteger(1, md.digest().toString(16); catch (Exception e) e.printStackTrace();return dstr;myOpenHelper java 源码package com.example.android;import android.content.ContentV alues;impor
11、t android.content.Context;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;public class myOpenHelper extends SQLiteOpenHelperprivate static final String DA TABASE_NAME = mysql.db;private static final String TABLE_NAME = user
12、info; private static final String CREA TE_TABLE = create table+ userinfo(_id integer primary key autoincrement, name text, telephone text, email text);private SQLiteDatabase db;myOpenHelper(Context context) super(context, DATABASE_NAME, null,2); public void onCreate (SQLiteDatabase db) this.db=db; d
13、b.execSQL(CREATE_TABLE);/tianjiapublic void insert(ContentV alues values) SQLiteDatabase db=getWritableDatabase(); db.insert(TABLE_NAME, null, values); db.close();/chaxunpublic Cursor query()SQLiteDatabase db=getWritableDatabase();Cursor cr=db.query(TABLE_NAME, null, null, null, null, null, null); r
14、eturn cr;/gengxinpublic void update(ContentV alues values) SQLiteDatabase db=getWritableDatabase(); db.update(TABLE_NAME, values, _id=8,null); db.close();/shanchu public void delete(int id)if(db=null) db=getWritableDatabase(); db.delete(TABLE_NAME, _id =?, new StringString.valueOf(id);/guanbi DA TAB
15、ASE public void colse() if(db!=null) db.close();Overridepublic void onUpgrade(SQLiteDatabase db, int oldV ersion, int newV ersion) / TODO Auto-generated method stubQueryActivity java 源码package com.example.android;import android.app.AlertDialog;import android.app.ListActivity;import android.content.D
16、ialogInterface;import android.database.Cursor;import android.os.Bundle;import android.widget.AdapterView;import android.widget.ListView;import android.widget.SimpleCursorAdapter;import android.widget.AdapterView.OnItemClickListener;public class QueryActivity extends ListActivitypublic void onCreate(
17、Bundle saveInstanceState)super.onCreate(saveInstanceState);this.setTitle(userinfo);final myOpenHelper mhelper=new myOpenHelper(this);final Cursor c=mhelper.query();final String from=_id,name,telephone,email;final int to=R.id.text0,R.id.text1,R.id.text2,R.id.text3;SimpleCursorAdapter adapter = new Si
18、mpleCursorAdapter(this,R.layout.queryrow, c, from, to);ListView lv = getListView();lv.setAdapter(adapter);final AlertDialog.Builder builder=new AlertDialog.Builder(this);lv.setOnItemClickListener(new OnItemClickListener()Overridepublic void onItemClick(AdapterView arg0, android.view.View arg1, int a
19、rg2, long arg3) final long temp=arg3;builder.setMessage( Do you really delete it?).setPositiveButton(Y es, new DialogInterface.OnClickListener() public void onClick(DialogInterface dialog,int which) mhelper.delete(int)temp); Cursor c=mhelper.query();final String from=_id,name,telephone,email;int to=
20、R.id.text0,R.id.text1,R.id.text2,R.id.text3;SimpleCursorAdapter adapter=new SimpleCursorAdapter(getApplicationContext(),R.layout.queryrow,c,from,to);ListView lv=getListView();lv.setAdapter(adapter);).setNegativeButton(NO,new DialogInterface.OnClickListener() public void onClick(DialogInterface dialog,int which) );AlertDialog ad=builder.create(); ad.show();); mhelper.close();