Android Studio入门者求助：点击按钮跳转至下一个Activity的代码示例

Hey there! As someone who’s just starting out with Android Studio, I totally get how wrapping your head around Activity navigation can feel a bit overwhelming at first. Let’s walk through exactly how to make a button jump to another Activity, with full, copy-pasteable code examples for both Kotlin and Java.

First things first—you need a destination Activity! In Android Studio:

• Right-click your app’s package name (usually under app/src/main/java/com/yourdomain/yourapp)
• Hover over New → Activity → select Empty Views Activity
• Name it SecondActivity and click Finish
  This will auto-generate both the SecondActivity class and its corresponding layout file activity_second.xml.

Open your main activity’s layout (usually activity_main.xml) and add a Button with a unique ID so we can reference it in code. Here’s a simple centered button using ConstraintLayout:

<!-- activity_main.xml -->
<?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">

    <Button
        android:id="@+id/btn_navigate_to_second"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Go to Second Activity"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

Now we need to tell the button what to do when it’s clicked. Below are examples for both Kotlin and Java—use whichever you’re working with!

Kotlin Version (MainActivity.kt) #

import android.content.Intent
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Button

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        // Find the button using its ID from the layout
        val navigateButton: Button = findViewById(R.id.btn_navigate_to_second)

        // Set a click listener to trigger the navigation
        navigateButton.setOnClickListener {
            // Create an Intent: this tells Android which Activity to start
            val intent = Intent(this, SecondActivity::class.java)
            
            // Optional: Pass data to the second Activity (example)
            intent.putExtra("USER_MESSAGE", "Hello from Main Activity!")
            
            // Launch the Second Activity
            startActivity(intent)
        }
    }
}

Java Version (MainActivity.java) #

import android.content.Intent;
import android.os.Bundle;
import android.widget.Button;
import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Find the button using its ID from the layout
        Button navigateButton = findViewById(R.id.btn_navigate_to_second);

        // Set a click listener to trigger the navigation
        navigateButton.setOnClickListener(v -> {
            // Create an Intent: this tells Android which Activity to start
            Intent intent = new Intent(MainActivity.this, SecondActivity.class);
            
            // Optional: Pass data to the second Activity (example)
            intent.putExtra("USER_MESSAGE", "Hello from Main Activity!");
            
            // Launch the Second Activity
            startActivity(intent);
        });
    }
}

When you create a new Activity via Android Studio, it automatically adds an entry to your AndroidManifest.xml file—but it’s good to double-check! Make sure you see something like this inside the <application> tag:

<activity
    android:name=".SecondActivity"
    android:exported="false" />

android:exported="false" is safe here because we’re only launching this Activity from within our app. If you ever need to launch it from outside (like via a deep link), you’d set this to true.

Bonus: Retrieve Data in the Second Activity #

If you added the optional extra data, here’s how to get it in SecondActivity:

Kotlin

// Inside SecondActivity's onCreate method
val message = intent.getStringExtra("USER_MESSAGE")
// You can then display this message in a TextView, for example

Java

// Inside SecondActivity's onCreate method
String message = getIntent().getStringExtra("USER_MESSAGE");

That’s all there is to it! Run your app, click the button, and you’ll jump straight to the second Activity. If you run into any issues, just double-check your IDs match between the layout and code, and that the Activity is registered in the manifest.

内容的提问来源于stack exchange，提问作者ASLAM C A