安卓开发慕课网课程代码

1. 登录
   public class ForinActivity extends AppCompatActivity {
   private SQLiteDatabase db;
   private Cursor cursor;
   private EditText e1,e2;
   private Button b1,b2;
   private String u,p;
   private Intent k;

   @Override
   protected void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   setContentView(R.layout.activity_forin);
   e1= (EditText) findViewById(R.id.editText4);
   e2= (EditText) findViewById(R.id.editText3);
   b1= (Button) findViewById(R.id.button9);
   b2= (Button) findViewById(R.id.button10);

   b1.setOnClickListener(new View.OnClickListener() {
       @Override
       public void onClick(View v) {
           u=e1.getText().toString();
           p=e2.getText().toString();
           SQLiteHelper h = new SQLiteHelper(ForinActivity.this,"test",null,1);
           db = h.getReadableDatabase();
   
           cursor=db.query("user2",new String[]{"name","password"},"name=? and password=?",new String[]{u,p},null,null,null);
           if(cursor.moveToFirst())
           {
               Toast.makeText(ForinActivity.this,"登录成功",Toast.LENGTH_LONG).show();
               Intent k=new Intent(ForinActivity.this,WelcomeActivity.class);
               startActivity(k);
           }
           else
           {
   
               Toast.makeText(ForinActivity.this,"登录失败",Toast.LENGTH_LONG).show();
           }
   
       }
   });

   2.注册
   public class Main2Activity extends AppCompatActivity {
   private Button b1,b2;
   private EditText n1,p1;
   private SQLiteDatabase db;
   @Override
   protected void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   setContentView(R.layout.activity_main2);
   b1=(Button)findViewById(R.id.button7);
   n1=(EditText)findViewById(R.id.editText);
   p1=(EditText)findViewById(R.id.editText2);

   b2= (Button) findViewById(R.id.button8);
   
   b1.setOnClickListener(new View.OnClickListener() {
       @Override
       public void onClick(View v) {
           SQLiteHelper h = new SQLiteHelper(Main2Activity.this,"test",null,1);
           db = h.getReadableDatabase();
           String n_ame = n1.getText().toString();
           String pasd = p1.getText().toString();
           Cursor cursor = db.query("user2",new String[]{"name"},"name=?",new String[]{n_ame},null,null,null);
           if(cursor.getCount()>0)
           {
               Toast.makeText(getBaseContext(), "该用户名已经存在！！", Toast.LENGTH_SHORT).show();
               return;
           }
   
           ContentValues values = new ContentValues();
           values.put("name",n_ame);
           values.put("password",pasd);
           db.insert("user2",null,values);
           System.out.println("注册成功");
       }
   });

   3.定时跳转
   public class WelcomeActivity extends AppCompatActivity {

// 定义一个跳转的意图Intent
private Intent i;

private TextView tv2;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_welcome);

    tv2=(TextView) findViewById(R.id.textView2);
    new CountDownTimer(10*1000,1000) {
        @Override
        public void onTick(long millisUntilFinished) {
            //此处写“还剩X秒”代码
            tv2.setText("还剩"+String.valueOf(millisUntilFinished/1000)+"秒");
        }

        @Override
        public void onFinish() {
            i = new Intent(WelcomeActivity.this,Main3Activity.class);
            startActivity(i);
        }
    }.start();

4.碎片
public class Main3Activity extends AppCompatActivity {
private TextView tv1,tv2,tv3,tv4,tv5;
private FragmentManager fm;//碎片管理器
private FragmentTransaction ft;//碎片事务；什么是事务
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main3);

    tv1 = (TextView)findViewById(R.id.textView);
    tv2 = (TextView)findViewById(R.id.textView2);
    tv3 = (TextView)findViewById(R.id.textView3);
    tv4 = (TextView)findViewById(R.id.textView4);
    tv5 = (TextView)findViewById(R.id.textView5);

    tv1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            fm = getFragmentManager();
            ft =fm.beginTransaction();//从这里事务
            ft.replace(R.id.rame1,new F1Fragment());
            ft.commit();//提交事务，到达这里

        }
    });

5.碎片Java
public class F1Fragment extends Fragment {

public F1Fragment() {
    // Required empty public constructor
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstaneState) {
    // Inflate the layout for this fragment
    View v  =inflater.inflate(R.layout.fragment_f1,null);
    return v;
}

}
6.创建数据库
public class SQLiteHelper extends SQLiteOpenHelper {

static int VERSION=1;

public SQLiteHelper(Context context, String name, CursorFactory factory, int version) {
    super(context, name, factory, version);
}

@Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL("create table user(name char(20),password char(20))");
    db.execSQL("create table user2(name string,password string)");

}
@Override
public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {

}

}
7.数据链接

public class MainActivity extends AppCompatActivity {
private Button b1,b2,b3,b4,b5,b6;
public SQLiteDatabase db;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

    b1 = (Button)findViewById(R.id.button);

    b1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            SQLiteHelper h = new SQLiteHelper(MainActivity.this,"test",null,1);
             db = h.getReadableDatabase();
            System.out.println("创建数据库成功");
        }
    });