本程序是由两个界面组成，一个是登陆界面，一个是显示界面。
1.首先编写数据库的建表代码，创建MyDatabaseHelper类，并在oncreate方法中创建两个数据库表。其中下述代码中的usertable是用户表，aaatable是行程表，代码如下：
public class MyDatabaseHelper extends SQLiteOpenHelper {
public static final String CREATE_usertable="create table usertable("+"id integer primary key,"
+"name text,"
+"password text)";
public static final String CREATE_aaatable="create table aaatable("+"aid integer primary key,"
+"aname text,"
+"amessage text,"
+"atime text,"
+"id integer)";
private Context mContext;
public MyDatabaseHelper(Context context , String name, SQLiteDatabase.CursorFactory factory,int version){
super(context,name,factory,version);
mContext=context;
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(CREATE_usertable);
db.execSQL(CREATE_aaatable);
Toast.makeText(mContext,"create aaaaaaa",Toast.LENGTH_SHORT).show();
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}2，编写登陆界面，在界面中放入两个EditView和一个button，本块很简单，不附代码了，主要是写两个EditView用于接收用户id和密码，然后一个确认的按钮
3.编写MainActivity函数，在函数中首先执行建立数据库代码，再调用MyDatabaseHelper的oncreate方法，再通过函数往数据库中插入表。再通过按钮点击事件，调用数据库的查询功能，查询数据库中是否有这条数据，有就跳到下一个页面，无就Toast一个密码错误的提示。
其中adddata（）是往数据库表里插入数据的，因此我们运行过一遍之后就把他注释掉，或者删掉，否则会报主键不唯一的错误，代码如下：
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private MyDatabaseHelper dbHelper;
private EditText ed1,ed2;
private Button bt1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ed1 = (EditText) findViewById(R.id.ed1);
ed2 = (EditText) findViewById(R.id.ed2);
bt1 = (Button) findViewById(R.id.bt1);
dbHelper = new MyDatabaseHelper(this, "16204204.db", null, 1);
dbHelper.getWritableDatabase();
bt1.setOnClickListener(this);
//adddata();
}
@Override
public void onClick(View view) {
String name=ed1.getText().toString();
String password=ed2.getText().toString();
SQLiteDatabase db=dbHelper.getWritableDatabase();
String sql = "select * from usertable where id=? and password=?";
Cursor cursor = db.rawQuery(sql, new String[] {name, password});
if (cursor.moveToFirst()) {
Bundle data=new Bundle();
data.putString("id",name);
Intent intent =new Intent(MainActivity.this,Main2Activity.class);
intent.putExtra("id",name);
startActivity(intent);
cursor.close();
}
else{
Toast.makeText(this, "密码输入错误，请重新输入", Toast.LENGTH_SHORT).show();
}
}
public void adddata(){
//添加数据
SQLiteDatabase db=dbHelper.getWritableDatabase();
ContentValues values =new ContentValues();
values.put("id",20);
values.put("name","jsc");
values.put("password","123456");
db.insert("usertable",null,values);
values.clear(); //第一条
values.put("id",21);
values.put("name","yzy");
values.put("password","123");
db.insert("usertable",null,values); //第二条
ContentValues values1 =new ContentValues();
values1.put("aid",1);
values1.put("aname","上海");
values1.put("amessage","旅游");
values1.put("atime","1.1");
values1.put("id",20);
db.insert("aaatable",null,values1);
values1.clear(); //第一条
values1.put("aid",2);
values1.put("aname","北京");
values1.put("amessage","办公");
values1.put("atime","1.1");
values1.put("id",20);
db.insert("aaatable",null,values1);
values1.clear(); //第二条
values1.put("aid",3);
values1.put("aname","广州");
values1.put("amessage","旅游");
values1.put("atime","1.3");
values1.put("id",21);
db.insert("aaatable",null,values1);
values1.clear(); //第一条
values1.put("aid",4);
values1.put("aname","深圳");
values1.put("amessage","办公");
values1.put("atime","1.2");
values1.put("id",21);
db.insert("aaatable",null,values1); //第二条
}
}4.编写第二个页面的xml，本页面有所有的功能的按钮和编辑栏，并且添加ListView，因为ListView可以较好得显示数据，我们采用ListView，所以第一个有ListView和增，改，删数据库的按钮和输入框;
5.编写text_item.xml，本块代码主要为ListView的显示;
6.编写usertable实体类，用于对ListView的数据写入的使用：
public class usertable {
int aid;
String aname;
String amessage;
String time;
int id;
public usertable(){
}
public usertable(int aid,String aname,String amessage,String time,int id){
this.aid=aid;
this.aname=aname;
this.amessage=amessage;
this.time=time;
this.id=id;
}
public int getAid() {
return aid;
}
public int getId() {
return id;
}
public String getAmessage() {
return amessage;
}
public String getAname() {
return aname;
}
public String getTime() {
return time;
}
public void setAid(int aid) {
this.aid = aid;
}
public void setAmessage(String amessage) {
this.amessage = amessage;
}
public void setAname(String aname) {
this.aname = aname;
}
public void setId(int id) {
this.id = id;
}
public void setTime(String time) {
this.time = time;
}
}7.编写TextAdapter类，用于对ListView的适配类，代码如下：
public class TextAdapter extends ArrayAdapter<usertable>{
private int resourceId;
public TextAdapter(Context context, int textViewResourceId, List<usertable> objects){
super(context,textViewResourceId,objects);
resourceId=textViewResourceId;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
usertable t=getItem(position);
View view= LayoutInflater.from(getContext()).inflate(resourceId,parent,false);
TextView aid=(TextView)view.findViewById(R.id.aid);
TextView aname=(TextView)view.findViewById(R.id.aname);
TextView amessage=(TextView)view.findViewById(R.id.amessage);
TextView time=(TextView)view.findViewById(R.id.time);
TextView id=(TextView)view.findViewById(R.id.id);
String a=""+t.getAid();
String b=""+t.getId();
aid.setText(a);
aname.setText(t.getAname());
amessage.setText(t.getAmessage());
time.setText(t.getTime());
id.setText(b);
return view;
}
}8，编写第二个页面的Activity代码，主要有对数据的增删改功能，代码如下：
public class Main2Activity extends AppCompatActivity implements View.OnClickListener {
private List<usertable> textList=new ArrayList<usertable>();
private MyDatabaseHelper dbHelper;
private EditText d1,a1,a2,a3,a4,a5,u1,u2,u3,u4;
private Button delect,add,upata;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
dbHelper = new MyDatabaseHelper(this, "16204204.db", null, 1);
dbHelper.getWritableDatabase();
System.out.print("ssss");
initmessage();
TextAdapter adapter=new TextAdapter(Main2Activity.this,R.layout.text_item,textList);
ListView listView=(ListView)findViewById(R.id.a);
listView.setAdapter(adapter);
delect=(Button)findViewById(R.id.delect);
delect.setOnClickListener(this);
add=(Button)findViewById(R.id.add);
add.setOnClickListener(this);
upata=(Button)findViewById(R.id.updata);
upata.setOnClickListener(this);
}
@Override
public void onClick(View view) {
switch (view.getId()){
case R.id.delect:
clickdelect();
break;
case R.id.add:
cilckadd();
break;
case R.id.updata:
cilckupdata();
break;
}
}
private void cilckupdata() {
u1=(EditText)findViewById(R.id.u1);
String updata1=u1.getText().toString();
u2=(EditText)findViewById(R.id.u2);
String updata2=u2.getText().toString();
u3=(EditText)findViewById(R.id.u3);
String updata3=u3.getText().toString();
u4=(EditText)findViewById(R.id.u4);
String updata4=u4.getText().toString();
SQLiteDatabase db=dbHelper.getWritableDatabase();
ContentValues values =new ContentValues();
values.put("aname",updata2);
values.put("amessage",updata3);
values.put("atime",updata4);
db.update("aaatable",values,"aid=?",new String[]{updata1});
Toast.makeText(this, "修改成功，请刷新或重新登陆", Toast.LENGTH_SHORT).show();
}
private void cilckadd() {
a1=(EditText)findViewById(R.id.a1);
String add1=a1.getText().toString();
a2=(EditText)findViewById(R.id.a2);
String add2=a2.getText().toString();
a3=(EditText)findViewById(R.id.a3);
String add3=a3.getText().toString();
a4=(EditText)findViewById(R.id.a4);
String add4=a4.getText().toString();
a5=(EditText)findViewById(R.id.a5);
String add5=a5.getText().toString();
int i=Integer.parseInt(add1);
int j=Integer.parseInt(add5);
SQLiteDatabase db=dbHelper.getWritableDatabase();
ContentValues values =new ContentValues();
values.put("aid",i);
values.put("aname",add2);
values.put("amessage",add3);
values.put("atime",add4);
values.put("id",j);
db.insert("aaatable",null,values);
Toast.makeText(this, "添加成功，请刷新或重新登陆", Toast.LENGTH_SHORT).show();
}
private void clickdelect() {
d1=(EditText)findViewById(R.id.d1);
String a=d1.getText().toString();
SQLiteDatabase db=dbHelper.getWritableDatabase();
db.delete("aaatable","aid=?",new String[]{ a});
Toast.makeText(this, "删除成功，请刷新或重新登陆", Toast.LENGTH_SHORT).show();
}
public void initmessage(){
Intent intent=getIntent();
Bundle b=intent.getExtras();
String name=b.getString("id");
SQLiteDatabase db=dbHelper.getWritableDatabase();
String sql = "select * from aaatable where id=? order by atime ";
Cursor cursor = db.rawQuery(sql, new String[] {name});
if (cursor.moveToFirst()) {
do {
int aid = cursor.getInt(cursor.getColumnIndex("aid"));
String aname = cursor.getString(cursor.getColumnIndex("aname"));
String amessage = cursor.getString(cursor.getColumnIndex("amessage"));
String time = cursor.getString(cursor.getColumnIndex("atime"));
int id = cursor.getInt(cursor.getColumnIndex("id"));
usertable user = new usertable(aid,aname,amessage,time,id);
textList.add(user);
}while (cursor.moveToNext());
}
cursor.close();
}
}9.代码编辑完后运行代码，效果如下：
登陆密码错误的情况：
密码登陆正确的情况，显示该id下的行程记录，可在下面的功能中添加，修改和删除：
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