<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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">
  
  
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent" android:layout_height="match_parent"
        android:paddingTop="200dp" android:paddingLeft="20dp">
  
        <Button
        android:layout_width="80dp"
        android:layout_height="80dp"
        android:id="@+id/btn1"
        android:text="111"
        android:background="#528654">
        </Button>
  
        <Button
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:id="@+id/btn2"
            android:text="222"
            android:layout_toRightOf="@id/btn1"
            android:background="#896899">
        </Button>
  
        <Button
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:id="@+id/btn3"
            android:text="333"
            android:layout_toRightOf="@id/btn2"
            android:background="#212360">
        </Button>
  
        <Button
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:id="@+id/btn4"
            android:text="444"
            android:layout_below="@id/btn1"
            android:background="#FF2589">
        </Button>
  
        <Button
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:id="@+id/btn5"
            android:text="555"
            android:layout_below="@id/btn1"
            android:layout_toRightOf="@id/btn4"
            android:background="#008854">
        </Button>
  
        <Button
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:id="@+id/btn6"
            android:text="666"
            android:layout_below="@id/btn1"
            android:layout_toRightOf="@id/btn5"
            android:background="#788877">
        </Button>
  
        <Button
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:id="@+id/btn7"
            android:text="777"
            android:layout_below="@id/btn4"
            android:background="#896888">
        </Button>
  
        <Button
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:id="@+id/btn8"
            android:text="888"
            android:layout_below="@id/btn4"
            android:layout_toRightOf="@id/btn7"
            android:background="#DD4588">
        </Button>
  
        <Button
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:id="@+id/btn9"
            android:text="999"
            android:layout_below="@id/btn4"
            android:layout_toRightOf="@id/btn8"
            android:background="#AA2548">
        </Button>
    </RelativeLayout>
  
</androidx.constraintlayout.widget.ConstraintLayout>
　　

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
  
    <ImageView
        android:id="@+id/photo"
        android:layout_width="80dp"
        android:layout_height="80dp"
        android:layout_centerInParent="true"
        android:src="@drawable/photo"></ImageView>
  
    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/photo"
        android:maxLength="15"
        android:layout_marginTop="13dp"
        android:text="账号："/>
  
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/photo"
        android:layout_toRightOf="@id/textView1"
        android:hint="请输入您的账号"></EditText>
  
  
    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/textView1"
        android:maxLength="20"
        android:layout_marginTop="25dp"
        android:text="密码：" />
  
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/textView1"
        android:layout_toRightOf="@id/textView2"
        android:layout_marginTop="10dp"
        android:hint="请输入您的密码">
    </EditText>
  
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/button"
        android:text="登录"
        android:textColor="#478595"
        android:layout_below="@id/textView2"
        android:layout_marginTop="20dp"
        android:layout_marginLeft="120dp"
        android:onClick="click">
    </Button>
  
</RelativeLayout>
package com.example.myhomework1;
  
import androidx.appcompat.app.AppCompatActivity;
  
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
  
public class MainActivity extends AppCompatActivity {
  
    private Button mybutton_one;
  
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
  
        mybutton_one = (Button) findViewById(R.id.button);
    }
  
  
    public void click(View view){
        mybutton_one.setText("登录按钮被点击");
    }
}