Activity组件

<?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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.hanqi.testapp1.MainActivity"
    android:orientation="vertical">
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="用户代码"
        android:id="@+id/et_usercode"/>
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="密码"
        android:id="@+id/et_password"
        android:inputType="textPassword"/>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="登录"
            android:onClick="bt2_OnClick"/>
        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="注册"
            android:onClick="bt1_OnClick"/>
    </LinearLayout>

</LinearLayout>

<?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"
    android:paddingBottom="16dp"
    android:paddingLeft="16dp"
    android:paddingRight="16dp"
    android:paddingTop="16dp"
    >

</LinearLayout>

<?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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.hanqi.testapp1.ZhuceActivity">
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="用户代码"
        android:id="@+id/et_usercode_1"/>
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="用户名称"
        android:id="@+id/et_username_1"
        android:layout_below="@id/et_usercode_1"/>
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="登录密码"
        android:id="@+id/et_password_1"
        android:layout_below="@id/et_username_1"
        android:inputType="textPassword"/>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true">

        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="取消"
            android:onClick="bt2_OnClick"/>
        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="确定"
            android:onClick="bt1_OnClick"/>

    </LinearLayout>
</RelativeLayout>

package com.hanqi.testapp1;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class ZhuceActivity extends AppCompatActivity {
    EditText et_usercode1;
    EditText et_password1;
    EditText et_username1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_zhuce);
        et_usercode1=(EditText)findViewById(R.id.et_usercode_1);
        et_usercode1=(EditText)findViewById(R.id.et_password_1);
        et_usercode1=(EditText)findViewById(R.id.et_username_1);
    }
    //view 代表事件发起者
    public void bt1_OnClick(View v)
    {
        //返回注册信息
        //用户代码
        String usercode=et_usercode1.getText().toString();
        if(usercode==null||usercode.trim().length()==0)
        {
            Toast.makeText(ZhuceActivity.this, "请正确填写用户代码", Toast.LENGTH_SHORT).show();
            return;
        }
        String username=et_username1.getText().toString();
        if(username==null||usercode.trim().length()==0)
        {
            Toast.makeText(ZhuceActivity.this, "请正确填写用户名称", Toast.LENGTH_SHORT).show();
            return;
        }
        String password=et_password1.getText().toString();
        if(password==null||usercode.trim().length()==0)
        {
            Toast.makeText(ZhuceActivity.this, "请正确填写用户密码", Toast.LENGTH_SHORT).show();
            return;
        }
        Intent intent =new Intent();
        intent.putExtra("usercode",usercode);
        intent.putExtra("username",username);
        intent.putExtra("password",password);
        setResult(RESULT_OK,intent);
        finish();
    }
}

package com.hanqi.testapp1;

/**
 * Created by Administrator on 2016/4/29.
 */
public class TestActivity {
}

package com.hanqi.testapp1;

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    EditText et_usercode;
    EditText et_password;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        et_usercode = (EditText) findViewById(R.id.et_usercode);
        et_password = (EditText) findViewById(R.id.et_password);
    }

    //view 代表事件的发起者
    public void bt1_OnClick(View v) {
        //带返回的打开 注册的Activity
        //1 构造意图
        Intent intent = new Intent(this, ZhuceActivity.class);
        startActivityForResult(intent, 1);
    }

    String usercode;
    String username;
    String password;
    //重写处理返回信息的回调方法

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        //处理返回信息
        //判断请求码
        if (resultCode == 1) {
            //判断结构码
            if (resultCode == RESULT_OK) {
                //接收返回的注册信息
                usercode = data.getStringExtra("usercode");
                username = data.getStringExtra("username");
                password = data.getStringExtra("password");
            }
        }
    }



    //登陆的方法
    public void bt2_OnClick(View v) {
        //1.取得填写信息
        //2.判断是否正确填写
        String uc = et_usercode.getText().toString();
        String pw = et_password.getText().toString();
        if (uc.trim().length() == 0 || pw.trim().length() == 0) {
            Toast.makeText(MainActivity.this, "用户代码和密码不能为空", Toast.LENGTH_SHORT).show();
            return;
        }

        //3.判断有没有注册信息
        //1)没有找到注册信息
        //2)填写的用户尚未注册
        if (usercode == null || (usercode != null && !usercode.equals(uc))) {
            Toast.makeText(MainActivity.this, "用户未注册", Toast.LENGTH_SHORT).show();
            return;
        }
        //4.判断登录信息和注册信息是否配
        if (!password.equals(pw)) {
            Toast.makeText(MainActivity.this, "密码错误", Toast.LENGTH_SHORT).show();
            return;
        }
        else
        {
            //可以登录系统了
            Toast.makeText(MainActivity.this, "用户验证成功", Toast.LENGTH_SHORT).show();
            //跳转到主界面
            Intent intent=new Intent(this,TestActivity.class);
            //传递数据
            //把数据放到Intent里
            intent.putExtra("usercode",usercode);
            intent.putExtra("username",username);
            startActivity(intent);
        }
    }
}