作业三

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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"
    tools:context=".MainActivity">

    <ImageView
        android:id="@+id/picture"
        android:layout_width="121dp"
        android:layout_height="116dp"
        android:layout_centerHorizontal="true"
        android:layout_marginStart="33dp"
        android:layout_marginLeft="33dp"
        android:layout_marginTop="100dp"
        android:layout_marginEnd="33dp"
        android:layout_marginRight="33dp"
        android:layout_marginBottom="30dp"
        android:src="@drawable/xiaoqie"
        app:layout_constraintBottom_toTopOf="@+id/editText1"
        app:layout_constraintEnd_toEndOf="@+id/editText1"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="@+id/editText1"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/editText2"
        android:layout_alignLeft="@+id/textView1"
        android:layout_alignBottom="@+id/editText2"
        android:layout_marginStart="48dp"
        android:layout_marginLeft="48dp"
        android:layout_marginEnd="25dp"
        android:layout_marginRight="25dp"
        android:text="密码:"
        android:textSize="20sp"
        app:layout_constraintBaseline_toBaselineOf="@+id/editText2"
        app:layout_constraintEnd_toStartOf="@+id/editText2"
        app:layout_constraintStart_toStartOf="parent" />

    <EditText
        android:id="@+id/editText2"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_below="@+id/editText1"
        android:layout_alignLeft="@+id/editText1"
        android:layout_marginEnd="92dp"
        android:layout_marginRight="92dp"
        android:layout_marginBottom="35dp"
        android:ems="10"
        app:layout_constraintBottom_toTopOf="@+id/btn"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@+id/textView2"
        app:layout_constraintTop_toBottomOf="@+id/editText1" />

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/btn"
        android:layout_alignBottom="@+id/editText1"
        android:layout_marginStart="48dp"
        android:layout_marginLeft="48dp"
        android:layout_marginEnd="25dp"
        android:layout_marginRight="25dp"
        android:text="账号:"
        android:textSize="20sp"
        app:layout_constraintBaseline_toBaselineOf="@+id/editText1"
        app:layout_constraintEnd_toStartOf="@+id/editText1"
        app:layout_constraintStart_toStartOf="parent" />

    <Button
        android:id="@+id/btn"
        android:layout_width="250dp"
        android:layout_height="wrap_content"
        android:layout_below="@+id/editText2"
        android:layout_alignParentRight="true"
        android:layout_marginBottom="200dp"
        android:background="#00FF7F"
        android:onClick="click"
        android:text="登录"
        android:textColor="#FFFFFF"
        app:layout_constraintBottom_toTopOf="@+id/tv"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.496"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/editText2" />

    <EditText
        android:id="@+id/editText1"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_below="@+id/picture"
        android:layout_marginEnd="92dp"
        android:layout_marginRight="92dp"
        android:layout_marginBottom="39dp"
        android:layout_toRightOf="@+id/textView1"
        android:ems="10"
        android:textColor="#000000"
        android:textSize="20sp"
        app:layout_constraintBottom_toTopOf="@+id/editText2"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@+id/textView1"
        app:layout_constraintTop_toBottomOf="@+id/picture">

        <requestFocus />
    </EditText>

    <TextView
        android:id="@+id/tv"
        android:layout_width="99dp"
        android:layout_height="44dp"
        android:layout_below="@+id/btn"
        android:layout_centerHorizontal="true"
        android:layout_marginStart="19dp"
        android:layout_marginLeft="19dp"
        android:layout_marginEnd="19dp"
        android:layout_marginRight="19dp"
        android:layout_marginBottom="41dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="@+id/editText2"
        app:layout_constraintHorizontal_bias="0.682"
        app:layout_constraintStart_toStartOf="@+id/editText2"
        app:layout_constraintTop_toBottomOf="@+id/btn" />
    />

</android.support.constraint.ConstraintLayout>

package com.example.qwer;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

    }

    private TextView textView;

    public void click(View view) {
        Button btn = (Button) findViewById(R.id.btn);
        EditText et1 = (EditText) findViewById(R.id.editText1);
        EditText et2 = (EditText) findViewById(R.id.editText2);
        textView = (TextView) findViewById(R.id.tv);
        switch (view.getId()) {
            case R.id.btn:

                String s1 = et1.getText().toString();
                String s2 = et2.getText().toString();
                if (s1.equals("123456") && s2.equals("abc123")) {
                    Toast.makeText(MainActivity.this, "登录成功", 0).show(); // 点击按钮时，在下面弹出消息框
                } else {
                    textView.setText("登录失败");
                }
        }
    }