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<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>