第4章 程序活动单元Activity
4.2 Activity的创建配置和关闭
4.2.1 Activity的创建
包名处单机右键选择【New】->【Activity】->【Empty Activity】选项,填写Activity信息,完成创建。
Activity Name:Activity名称
Layout Name:布局名称
Package Name:包名
4.2.2 配置Activity
- 包名处点击右键选择【New】->【Java Class】选项,填写Java类名,完成创建。在该类中继承Activity。
- 当启动该Activity时,会抛出异常信息
- 在AndroidManifest.xml文件的<application></application>标签中配置Activity:
<activity android:name="com.ywp.activitybasic.SecondActivity"
4.2.3 开启和关闭Activity
- 开启Activity:startActivity()
- 在MainActivity的onCreate()方法中启动SecondActivity
Intent intent = new Intent(MainActivity.this, SecondActivity.class);
stratActivity(intent);
- 关闭Activity:finish()
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
android:orientation="vertical">
<Button
android:id="@+id/start"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="打开Activity"/>
<Button
android:id="@+id/finish"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="关闭Activity"/>
</LinearLayout>
package com.ywp.startactivity;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
findViewById(R.id.start).setOnClickListener(this);
findViewById(R.id.finish).setOnClickListener(this);
}
@Override
public void onClick(View view) {
switch (view.getId()) {
case R.id.start: //打开Activity的按钮
Intent intent = new Intent(MainActivity.this, SecondActivity.class);
startActivity(intent);
break;
case R.id.finish: //关闭Activity的按钮
finish();
break;
}
}
}