Android实现登录界面功能和实现详解

两个编辑框

一个输入账号 ，一个输入密码

一个按钮

点击按钮登录

判断账号和密码不为空

设置账号必须以字母开头

验证密码最小为8位，最大16位

设置可显示隐藏密码

最终运行效果如下

public class MainActivity extends AppCompatActivity {
    private EditText et_name,et_pass;
    SharedPreferences share;
    CheckBox cb;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        et_name=(EditText)findViewById(R.id.et_name);
        et_pass=(EditText)findViewById(R.id.et_pass);
        cb=(CheckBox)findViewById(R.id.cb);
        cb.setOnCheckedChangeListener(new CheckClick());

        share=getSharedPreferences("login",MODE_PRIVATE);

        String name=share.getString("name","");
        String pass=share.getString("pass","");
        if(!name.isEmpty() && !pass.isEmpty()){
            et_name.setText(name);
            et_pass.setText(pass);
        }
        Intent intent=new Intent(MainActivity.this,Main2Activity.class);
        startActivity(intent);
    }

    public void login(View view){
        String name=et_name.getText().toString();
        String pass=et_pass.getText().toString();

        Log.i("MainActivity",name.isEmpty()+"");
        if(name.isEmpty() || pass.isEmpty()){
            Toast.makeText(MainActivity.this,"账号密码都不能为空",Toast.LENGTH_SHORT).show();
            return;
        }
        String first=name.substring(0,1);
        if(!first.matches("[a-zA-Z]")){
            Toast.makeText(MainActivity.this,"账号必须以字母开头",Toast.LENGTH_SHORT).show();
            return;
        }

        if(pass.length()>=8 && pass.length()<=16){
            SharedPreferences.Editor edit = share.edit();
            edit.putString("name",name);
            edit.putString("pass",pass);
            edit.commit();

            Intent intent=new Intent(MainActivity.this,Main2Activity.class);
            startActivity(intent);
        }else {
            Toast.makeText(MainActivity.this,"密码必须为8-16位", Toast.LENGTH_LONG).show();
        }
    }

    class CheckClick implements CompoundButton.OnCheckedChangeListener{

        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            Log.i("MainActivtiy",""+isChecked);
            if(isChecked){
                //密文
                et_pass.setTransformationMethod(PasswordTransformationMethod.getInstance());
                cb.setText("隐藏密码");
            }else {
                //明文
                et_pass.setTransformationMethod(HideReturnsTransformationMethod.getInstance());
                cb.setText("显示密码");
            }
        }
    }
}

第二个主体类

public class Main2Activity extends AppCompatActivity {
    private TabHost tabHost;
    private ViewPager vp;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        tabHost=(TabHost)findViewById(R.id.tabhost);
        vp=(ViewPager)findViewById(R.id.vp);
        tabHost.setup();
        tabHost.addTab(tabHost.newTabSpec("tag1").setIndicator("标题1").setContent(R.id.vp));
        tabHost.addTab(tabHost.newTabSpec("tag2").setIndicator("标题2").setContent(R.id.vp));

        List list=new ArrayList<>();
        Fragment1 fragment1=new Fragment1();
        Fragment2 fragment2=new Fragment2();
        list.add(fragment1);
        list.add(fragment2);
        Myadapter myadapter=new Myadapter(getSupportFragmentManager(),list);
        vp.setAdapter(myadapter);
        tabHost.setOnTabChangedListener(new TabHost.OnTabChangeListener() {
            @Override
            public void onTabChanged(String tabId) {
                if(tabId.equals("tag1")){
                    vp.setCurrentItem(0);
                }else {
                    vp.setCurrentItem(1);
                }
            }
        });
        //vp.setCurrentItem(0);
        tabHost.setCurrentTabByTag("tag1");
    }

    @Override
    protected void onResume() {
        super.onResume();
        vp.setCurrentItem(1);
        vp.setCurrentItem(0);
    }
}

第一个页面

public class Fragment1 extends Fragment {
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View inflate = inflater.inflate(R.layout.fragment1, null);
        Button btn=(Button) inflate.findViewById(R.id.btnstart);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent=new Intent("org.frxm.zhoukao3.MyReceiver");
                getActivity().sendBroadcast(intent);
            }
        });
        return inflate;
    }
}

第二个页面

public class Fragment2 extends Fragment {
    MyDbOpenHelper helper;
    SQLiteDatabase db;
    ListView lv;
    Context context;
    SimpleCursorAdapter adapter;
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View inflate = inflater.inflate(R.layout.fragment2, null);
        lv=(ListView)inflate.findViewById(R.id.lv);
        context=getActivity();
        helper=new MyDbOpenHelper(context);
        db=helper.getWritableDatabase();
        db.delete("info",null,null);

        for (int i=0;i<10;i++){
            ContentValues cv=new ContentValues();
            cv.put("name","我是"+i);
            db.insert("info",null,cv);
        }
        Toast.makeText(context,"插入成功",Toast.LENGTH_SHORT).show();

        Cursor info = db.query("info", null, null, null, null, null, null);
        adapter=new SimpleCursorAdapter(context,R.layout.list_item,info,
                new String[]{"_id","name"},new int[]{R.id.id,R.id.name},
                CursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER);
        lv.setAdapter(adapter);
        registerForContextMenu(lv);
        return inflate;
    }

    @Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
        super.onCreateContextMenu(menu, v, menuInfo);
        menu.add(0,1, Menu.NONE,"修改");
        menu.add(0,2,Menu.NONE,"删除");
    }

    @Override
    public boolean onContextItemSelected(MenuItem item) {
        AdapterView.AdapterContextMenuInfo view=( AdapterView.AdapterContextMenuInfo)item.getMenuInfo();
        int position = view.position;
        //获取索引对应的行的内容
        Cursor cursor=(Cursor) adapter.getItem(position);
        int _id = cursor.getInt(0);
        switch (item.getItemId()){
            case 1://修改
                ContentValues cv=new ContentValues();
                cv.put("name","修改后的值");
                int info1 = db.update("info", cv, "_id=?", new String[]{String.valueOf(_id)});
                if(info1>0){
                    Toast.makeText(context,"修改成功", Toast.LENGTH_LONG).show();
                }
                break;
            case 2://删除
                int info2 = db.delete("info", "_id=?", new String[]{String.valueOf(_id)});
                if(info2>0){
                    Toast.makeText(context,"删除成功",Toast.LENGTH_SHORT).show();
                }
                break;
        }
        Cursor info = db.query("info", null, null, null, null, null, null);
        adapter.changeCursor(info);
        return super.onContextItemSelected(item);
    }
}

适配器

public class Myadapter extends FragmentStatePagerAdapter {
    List list;
    public Myadapter(FragmentManager fm, List list) {
        super(fm);
        this.list=list;
    }

    @Override
    public Fragment getItem(int position) {
        return list.get(position);
    }

    @Override
    public int getCount() {
        return list.size();
    }
}

OpenHelper

public class MyDbOpenHelper extends SQLiteOpenHelper{
    private final static String name="mydb.db";
    private final static int version=1;
    public MyDbOpenHelper(Context context) {
        super(context, name, null, version);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("create table info(_id integer primary key autoincrement,name varchar(10))");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }
}

接受者

public class MyReceiver extends BroadcastReceiver {
    public MyReceiver() {
    }

    @Override
    public void onReceive(Context context, Intent intent) {
        NotificationManager manager=(NotificationManager)context.getSystemService(Context.NOTIFICATION_SERVICE);
        NotificationCompat.Builder builder=new NotificationCompat.Builder(context);
        builder.setSmallIcon(R.mipmap.ic_launcher);
        builder.setContentTitle("标题");
        builder.setContentText("我就是发送的内容");
        manager.notify(1,builder.build());
    }
}

主体布局

"1.0" encoding="utf-8"?>
"http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="org.frxm.zhoukao3.MainActivity">


        android:id="@+id/et_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:inputType="text"
        android:digits="@string/name_match"
        android:hint="请输入账号" />

        android:id="@+id/et_pass"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:inputType="numberPassword"
        android:hint="请输入密码"
        android:onClick="login"
        />

        android:id="@+id/cb"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="隐藏密码"
        android:checked="true"
        />

        android:id="@+id/login"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="登录"
        android:gravity="center"
        android:onClick="login"
        />

第二个主体布局

"1.0" encoding="utf-8"?>
"http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main2"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="org.frxm.zhoukao3.Main2Activity">

        android:id="@+id/tabhost"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

            android:orientation="vertical"
            android:layout_width="match_parent"
            android:layout_height="match_parent">

                android:id="@android:id/tabs"
                android:layout_width="match_parent"
                android:layout_height="wrap_content">


                android:id="@android:id/tabcontent"
                android:layout_width="match_parent"
                android:layout_height="match_parent">

                    android:id="@+id/vp"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent">

第一个页面布局

"1.0" encoding="utf-8"?>
"http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

        android:id="@+id/btnstart"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="发送广播"
        />

第二个页面布局

"1.0" encoding="utf-8"?>
"http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

        android:id="@+id/lv"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        />

list_item布局

"1.0" encoding="utf-8"?>
"http://schemas.android.com/apk/res/android"
    android:orientation="horizontal" android:layout_width="match_parent"
    android:layout_height="match_parent">

        android:id="@+id/id"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"/>

        android:id="@+id/name"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"/>