1、创建两个Activity并配置好Layout和AndroidManifest.xml

一、创建

--------------------------MainActivity----------------------------------

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.admin.webchanjian.MainActivity">


    <Button
        android:id="@+id/btn_open"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/btn_open"
        android:textSize="35dp"
        />
</RelativeLayout>

private Button btn_open;
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btn_open=(Button) findViewById(R.id.btn_open);
        btn_open.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent=new Intent();
                intent.setClass(MainActivity.this,Main2Activity.class);
                startActivity(intent);//打开Main2Activity
            }
        });
    }

---------------------Main2Activity-----------------------------------------------

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.admin.webchanjian.Main2Activity">
<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="@string/text_value"
    android:textSize="50sp"
    />
</RelativeLayout>

package com.example.admin.webchanjian;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class Main2Activity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
    }
}

 -----------------------配置AndroidManifest.xml---------------------------------

<activity android:name=".MainActivity">
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />

        <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>
</activity>
<activity android:name=".Main2Activity"></activity>

Intent打开Activity