Intent打开Activity

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>