Android RelativeLayout布局

例题2-8

activity_main.xml代码

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    xmlns:android="http://schemas.android.com/apk/res/android">
    <TextView
        android:id="@+id/label"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="输入一串字符"
        android:gravity="center"/>
    <EditText
        android:id="@+id/txt"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/label"
        android:hint="在这里输入123"/>
    <Button
        android:id="@+id/but1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="重置"
        android:layout_below="@id/txt"/>
    <Button
        android:id="@+id/but2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="确认"
        android:layout_toRightOf="@id/but1"
        android:layout_marginLeft="150dp"
        android:layout_below="@+id/txt"/>
    <TextView
        android:id="@+id/labe2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/but2"
        android:gravity="center"/>
</RelativeLayout>

Mainactivity代码

package com.example.hello;

import androidx.appcompat.app.AppCompatActivity;

import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
    private TextView txt;
    private TextView txt2;
    private Button button1;
    private Button button2;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        txt = (TextView)findViewById(R.id.labe2);
        txt2 = (TextView)findViewById(R.id.txt);
        button1 = (Button)findViewById(R.id.but1);
        button2 = (Button)findViewById(R.id.but2);
        button1.setOnClickListener(new bClick());
        button2.setOnClickListener(new mClick());
    }

    class mClick implements View.OnClickListener {
        public void onClick(View view){
            txt.setText("输入成功");
        }
    }
    class bClick implements View.OnClickListener {
        public void onClick(View view){
            txt2.setText("");
        }
    }
}