button，textview，editview的简单示例

A simple example of button usage
activity_main,xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"

    android:orientation="vertical"
    android:showDividers="middle"
    android:dividerPadding="10dp"
    tools:context="com.example.xxxx.myapplication.MainActivity" >


    <TextView
        android:id="@+id/txt1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textStyle="bold"
        android:textSize="20dp"
        android:text="1" />

    <EditText
        android:id="@+id/et1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:inputType="none"
        android:hint="1" />

    <TextView
        android:id="@+id/txt2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textStyle="bold"
        android:textSize="20dp"
        android:text="2 "/>


    <EditText
        android:id="@+id/et2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="2 " />


    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/bt1"
        android:text="S" />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/bt2"
        android:text="R" />

    <TextView
        android:id="@+id/txt"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textStyle="bold"
        android:textSize="18dp" />

</LinearLayout>

mainActivity.java

package com.example.xxxx.myapplication;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;


public class MainActivity extends AppCompatActivity {

    //TextView txt =findViewById(R.id.show_msg);

    private Button button1,button2;

    TextView txt;
    //TextView txt2 =findViewById(R.id.txt2);

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        this.txt=(TextView)this.findViewById(R.id.txt);

        //BUTTON1 111
        this.button1 = (Button) this.findViewById(R.id.bt1);
        this.button1.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                EditText et1=(EditText)findViewById(R.id.et1);
                String s1 = et1.getText().toString();
                txt.setText("@11111"+s1);
                }
            });


        //BUTTON2 222
        this.button2 = (Button) this.findViewById(R.id.bt2);
        this.button2.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                EditText et2=(EditText)findViewById(R.id.et2);
                String s2 = et2.getText().toString();
                txt.setText("@22222"+s1);
            }
        });
    }
}