Activity创建与跳转

• layout目录下新建activity_main2.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"><TextViewandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:text="@string/text2"tools:ignore="MissingConstraints" /></androidx.constraintlayout.widget.ConstraintLayout>

• 修改strings.xml

<resources><string name="app_name">demo</string><!-- 添加如下 --><string name="text2">Activity Main 2</string>
</resources>

• 新建MainActivity2

package com.example.demo;import android.os.Bundle;
import androidx.appcompat.app.AppCompatActivity;public class MainActivity2 extends AppCompatActivity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main2);}}

• AndroidManifest.xml中添加如下

<activity android:name=".MainActivity2" />

• 修改activity_main.xml，编写添加按钮

<Buttonandroid:id="@+id/button"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="跳转"tools:ignore="MissingConstraints" />

• 修改MainActivity

package com.example.demo;import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;public class MainActivity extends AppCompatActivity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);// 添加如下Button button = findViewById(R.id.button);button.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {Intent intent = new Intent();intent.setClass(MainActivity.this, MainActivity2.class);startActivity(intent);}});}
}

• 启动测试