Question

到目前为止。我在Android Studio上创建了一个简单的测验应用程序。一切正常，包括当我从FirstActivity.java转到Next Activity（名为SecondActivity.java），并在按下按钮时关闭第一个带有finish（）的活动，如下面的代码所示：

 public void onClick () {   

    button_next = (Button)findViewById(R.id.nextbtn);


            button_next.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    startActivity(new Intent(FirstActivity.this, SecondActivity.class));
                    finish();


                }
            });

代码工作正常但是当我尝试从第二个活动转到第一个活动（关闭第二个活动并返回到第一个活动）时，finish（）和onBackPressed（）都不起作用，它只是关闭完全应用程序，我按下按钮后需要什么代码，关闭SecondActivity.class并转到FirstActivity.class？

Answer 1

如果您想返回之前的活动，请在更改活动后不要完成。

library(RSelenium)

pJS <- phantom() # start phantomjs

appURL <- 'https://www.optionslam.com/accounts/login/'
remDr <- remoteDriver(browserName = "phantomjs")
remDr$open()
remDr$navigate(appURL)
remDr$findElement("id", "id_username")$sendKeysToElement(list("user"))
remDr$findElement("id", "id_password")$sendKeysToElement(list("password", key='enter'))

appURL <- 'https://www.optionslam.com/earnings/stocks/MSFT?page=-1'
remDr$navigate(appURL)

Answer 2

如果您有这么多活动，还有另一种处理活动生命周期的方法：

if [ "$(( width >= 500 ? 1 : 0))" = 1 ]

在FirstActivity，你应该添加

public class MyActivityManager { private static MyActivityManager instance; private Stack<Activity> activityStack;//activity's stack private MyActivityManager() { } //singleton public static MyActivityManager getInstance() { if (instance == null) { instance = new MyActivityManager(); } return instance; } //push an activity to stack public void pushOneActivity(Activity actvity) { if (activityStack == null) { activityStack = new Stack<Activity>(); } activityStack.add(actvity); } //get last activity，fifo public Activity getLastActivity() { return activityStack.lastElement(); } //remove an activity public void popOneActivity(Activity activity) { if (activityStack != null && activityStack.size() > 0) { if (activity != null) { activity.finish(); activityStack.remove(activity); activity = null; } } } //finish all activity public void finishAllActivity() { if (activityStack != null) { while (activityStack.size() > 0) { Activity activity = getLastActivity(); if (activity == null) break; popOneActivity(activity); } } } }

在SecondActivity，您想要参加FirstActivity或其他活动：

MyActivityManager.getInstance().pushOneActivity(FirstActivity.this);

Android Studio后退按钮问题

2 个答案: