Android实现登录界面功能和实现详解

待我称王封你为后i 2022-06-06 02:11 216阅读 0赞

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

![Center][]

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<Fragment> 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<Fragment> list;
        public Myadapter(FragmentManager fm, List<Fragment> 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

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="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">
    
        <EditText
            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" />
        <EditText
            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"
            />
        <CheckBox
            android:id="@+id/cb"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="隐藏密码"
            android:checked="true"
            />
        <Button
            android:id="@+id/login"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="登录"
            android:gravity="center"
            android:onClick="login"
            />
    </LinearLayout>

第二个主体布局

<?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="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">
        <TabHost
            android:id="@+id/tabhost"
            android:layout_width="match_parent"
            android:layout_height="match_parent">
            <LinearLayout
                android:orientation="vertical"
                android:layout_width="match_parent"
                android:layout_height="match_parent">
                <TabWidget
                    android:id="@android:id/tabs"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"></TabWidget>
    
                <FrameLayout
                    android:id="@android:id/tabcontent"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent">
                    <android.support.v4.view.ViewPager
                        android:id="@+id/vp"
                        android:layout_width="match_parent"
                        android:layout_height="match_parent">
    
                    </android.support.v4.view.ViewPager>
                </FrameLayout>
            </LinearLayout>
    
        </TabHost>
    
    </RelativeLayout>

第一个页面布局

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical" android:layout_width="match_parent"
        android:layout_height="match_parent">
        <Button
            android:id="@+id/btnstart"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="发送广播"
            />
    </LinearLayout>

第二个页面布局

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical" android:layout_width="match_parent"
        android:layout_height="match_parent">
        <ListView
            android:id="@+id/lv"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            />
    </LinearLayout>

list\_item布局

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="horizontal" android:layout_width="match_parent"
        android:layout_height="match_parent">
        <TextView
            android:id="@+id/id"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"/>
        <TextView
            android:id="@+id/name"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"/>
    </LinearLayout>

[Center]: /images/20220606/59d65c2dc10d4d89afdd2c37dc51f38a.png