安卓实现简单的登录注册

package com.example.test1;import android.app.Activity;import android.app.AlertDialog;import android.app.AlertDialog.Builder;import android.content.DialogInterface;import android.content.Intent;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.os.Bundle;import android.view.KeyEvent;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.EditText;import android.widget.LinearLayout;import android.widget.Toast;public class MainActivity extends Activity implements OnClickListener{ /** Called when the activity is first created. *///private static final String PREFS_NAME = "MyInfo";//用来保存用户信息 public static EditText Num,Pwd; private static Button Login,Post,pwdback; //public static CheckBox RememberPwd,AutoLogin;private DBHelper dbHelper;public static SQLiteDatabase sdb; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main);// AppConnect.getInstance(this);//LinearLayout container =(LinearLayout)findViewById(R.id.AdLinearLayout); //new AdView(this,container).DisplayAd(); //获得实例对象 Num=(EditText) findViewById(R.id.et_Num); Pwd=(EditText) findViewById(R.id.et_Pwd); Login=(Button) findViewById(R.id.btn_Login); Post=(Button) findViewById(R.id.Post); pwdback = (Button) findViewById(R.id.pwdback); Post.setOnClickListener(this); Login.setOnClickListener(this); pwdback.setOnClickListener(this); dbHelper=new DBHelper(this,"Info.db"); //LoadUserDate(); }@Overridepublic void onClick(View v) {// TODO Auto-generated method stubswitch(v.getId()){ case R.id.btn_Login: if(Num.getText().toString().equals("")){Toast.makeText(MainActivity.this,"姓名不能为空 ", Toast.LENGTH_SHORT).show();return;}if(Pwd.getText().toString().equals("")){Toast.makeText(MainActivity.this,"号码不能为空 ", Toast.LENGTH_SHORT).show();return;}//SaveUserDate();boolean bool=login(Num.getText().toString(),Pwd.getText().toString());if(bool){Toast.makeText(MainActivity.this, "登录成功！", Toast.LENGTH_LONG).show();Intent intent = new Intent();intent.putExtra("name",Num.getText().toString());intent.setClass(MainActivity.this, AfterLogin.class); MainActivity.this.startActivity(intent);}else{Toast.makeText(MainActivity.this, "用户名或密码有误！", Toast.LENGTH_LONG).show();return;} break; case R.id.Post: Intent intent=new Intent(MainActivity.this,Register.class); startActivity(intent);break; case R.id.pwdback: //System.out.println("被响应"); Intent intent1 = new Intent();//intent.putExtra("name",Num.getText().toString());intent1.setClass(MainActivity.this, pwdback.class);MainActivity.this.startActivity(intent1);break;}} //登录 public boolean login(String username,String password){ String name = new Security().Encryption(username); String pwd = new Security().Encryption(password); /*SQLiteDatabase*/ sdb=dbHelper.getReadableDatabase(); String sql="select * from people where name=? and pwd=?"; Cursor cursor=sdb.rawQuery(sql, new String[]{name,pwd}); if(cursor.moveToFirst()==true){ cursor.close(); return true; } return false; } //退出 public boolean onKeyDown(int keyCode, KeyEvent event) { if (keyCode == KeyEvent.KEYCODE_BACK ) { AlertDialog.Builder builder = new Builder(MainActivity.this); builder.setIcon(android.R.drawable.ic_dialog_info); builder.setMessage("确定要退出?"); builder.setTitle("提示"); builder.setPositiveButton("确认", new android.content.DialogInterface.OnClickListener() {public void onClick(DialogInterface dialog, int which) { dialog.dismiss(); MainActivity.this.finish();} }); builder.setNegativeButton("取消", new android.content.DialogInterface.OnClickListener() {public void onClick(DialogInterface dialog, int which) { dialog.dismiss();} }); builder.create().show(); } return false; } // /**// * 保存用户信息// *///private void SaveUserDate() {//// 载入配置文件//SharedPreferences sp = getSharedPreferences(PREFS_NAME, 0);//// 写入配置文件//Editor spEd = sp.edit();//if (RememberPwd.isChecked()) {//spEd.putBoolean("isSave", true);//spEd.putString("name", Num.getText().toString());//spEd.putString("password", Pwd.getText().toString());//} else {//spEd.putBoolean("isSave", false);//spEd.putString("name", "");//spEd.putString("password", "");//}//spEd.commit();//}/////**// * 载入已记住的用户信息// *///private void LoadUserDate() {//SharedPreferences sp = getSharedPreferences(PREFS_NAME, 0);////if (sp.getBoolean("isSave", false)) {//String username = sp.getString("name", "");//String userpassword = sp.getString("password", "");//if (!("".equals(username) && "".equals(userpassword))) {//Num.setText(username);//Pwd.setText(userpassword);//RememberPwd.setChecked(true);//}//}//} }