Mainactivity佈局檔案

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
 

    android:orientation="vertical"
    android:gravity="center_vertical"
    tools:context="com.example.administrator.taofirst.MainActivity">

    <android.support.design.widget.TextInputLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <EditText
            android:id="@+id/et_username"
 

            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="使用者名稱"
            android:maxLength="10"/>
    </android.support.design.widget.TextInputLayout>
    <android.support.design.widget.TextInputLayout
        android:layout_width="match_parent"
 

        android:layout_height="wrap_content"
        android:hint="密碼">

        <EditText
            android:id="@+id/et_password"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />
    </android.support.design.widget.TextInputLayout>
    <android.support.v7.widget.ButtonBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center">
        <Button
            android:id="@+id/bt_login"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="登陸"
            android:layout_gravity="center"/>
        <Button
            android:id="@+id/bt_regist"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="註冊"
            android:layout_gravity="center"/>
    </android.support.v7.widget.ButtonBarLayout>

</LinearLayout>

Mainactivity 的Java程式碼

package com.example.administrator.taofirst;

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

public class MainActivity extends AppCompatActivity {
    EditText editText=null;
    EditText editText1=null;
    Button button=null;
    Button button1=null;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        editText=(EditText) findViewById(R.id.et_username);
        editText1=(EditText) findViewById(R.id.et_password);
        button=(Button) findViewById(R.id.bt_login);
        button1=(Button) findViewById(R.id.bt_regist);
        button.setOnClickListener(mylistener);
        button1.setOnClickListener(mylistener);
    }
    private  String[]ss=new String[2];
   private View.OnClickListener mylistener =new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        String  username=editText.getText().toString().trim();
        String  password=editText1.getText().toString().trim();
        ss[0]=username;
        ss[1]=password;
        switch (v.getId())
        {
            case R.id.bt_login:
            {
                //Toast.makeText(MainActivity.this,"使用者名稱"+username+"-密碼"+password,Toast.LENGTH_SHORT).show();

                AlertDialog.Builder builder=new AlertDialog.Builder(MainActivity.this);
                builder.setTitle("登入資訊");
                builder.setItems(ss, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
//                        Toast.makeText(MainActivity.this,"u",Toast.LENGTH_SHORT).show();
                    }
                });
                AlertDialog alertDialog=builder.create();
                alertDialog.show();
                break;
            }
            case R.id.bt_regist:
            {
                Intent intent=new Intent();
                intent.setClass(MainActivity.this,RedisrerActivity.class);
                MainActivity.this.startActivity(intent);
                break;
            }
        }
    }};
}

著重強調在一個activity中呼叫另一個activity的方法

Intent intent=new Intent();
                intent.setClass(MainActivity.this,RedisrerActivity.class);
MainActivity.this.startActivity(intent);//還可以用intent傳送資料