【安卓开发】按钮点击事件

布局

<?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">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="#00BCD4"
        android:orientation="vertical">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="215dp"
            android:background="#FFFFFF"
            android:orientation="horizontal">

            <ImageView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_margin="10dp"
                android:src="@drawable/tu1" />
        </LinearLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="#FFFFFF"
            android:orientation="vertical">

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:background="#FFFFFF"
                android:orientation="horizontal">

                <ImageView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_weight="1"
                    android:id="@+id/image1"
                    android:src="@mipmap/ic_launcher"></ImageView>

                <ImageView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_weight="1"
                    android:src="@mipmap/ic_launcher"></ImageView>

                <ImageView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_weight="1"
                    android:src="@mipmap/ic_launcher"></ImageView>
            </LinearLayout>

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:background="#FFFFFF"

                android:orientation="horizontal">

                <ImageView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_weight="1"
                    android:src="@mipmap/ic_launcher"></ImageView>

                <ImageView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_weight="1"
                    android:src="@mipmap/ic_launcher"></ImageView>

                <ImageView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_weight="1"
                    android:src="@mipmap/ic_launcher"></ImageView>
            </LinearLayout>
            <Button
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="OPEN"
                android:id="@+id/Button1"
                >
            </Button>
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Hello,world!"
                android:id="@+id/text1"
                >

            </TextView>
        </LinearLayout>

    </LinearLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

Java控制文件

package com.huangenet.myapplication;

import android.annotation.SuppressLint;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {
    private Button Button1;
    private ImageView image1;
    private TextView text1;

    //参数初始化

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

        Button1=findViewById(R.id.Button1);//寻找布局文件里ID与自己定义的绑定
        Button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //打印
                System.out.println("Hello!");
                //弹窗
                Toast.makeText(MainActivity.this,"hello",Toast.LENGTH_LONG).show();
            }
        });
        image1=findViewById(R.id.image1);
        image1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //弹窗
                Toast.makeText(MainActivity.this,"This a image!",Toast.LENGTH_LONG).show();
            }
        });
        text1=findViewById(R.id.text1);
        text1.setText("你好，2020年3月29日20:18:45");

    }
}