How to open a second activity on click of button in android app

Question

I am learning to build android applications and I need some specific help. I can't seem to get my head around which bits of template code I am required to change, and which bits are static.

In the LAYOUT folder I have my ACTIVITY_MAIN.XML which reads

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout 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:orientation="horizontal">

 <Button
    android:id="@+id/button1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="@string/main_buttons_photos" />

 </LinearLayout>

Next, I have my second activity ACTIVITY_SEND_PHOTOS.XML which is

 <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" >

 <TextView
    android:id="@+id/textView2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_centerVertical="true"
    android:text="@string/hello_world"
    tools:context=".SendPhotos" />

 <TextView
    android:id="@+id/textView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true"
    android:text="@string/title_activity_send_photos"
    android:textAppearance="?android:attr/textAppearanceLarge" />

 </RelativeLayout>

I then have my MainActivity.java (is this the .class?) this reads package com.example.assent.bc;

 import android.os.Bundle;
 import android.app.Activity;
 import android.view.Menu;
 import android.view.View;

 public class MainActivity extends Activity {

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

 @Override
 public boolean onCreateOptionsMenu(Menu menu) {
     getMenuInflater().inflate(R.menu.activity_main, menu);
     return true;
 }
 /** Called when the user clicks the Send button */
 public void sendMessage(View view) {
     // Do something in response to button
 }
 }

and then my SendPhotos.java file which is;

 package com.example.assent.bc;

 import android.os.Bundle;
 import android.app.Activity;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.support.v4.app.NavUtils;

 public class SendPhotos extends Activity {

 @Override
 public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_send_photos);
    getActionBar().setDisplayHomeAsUpEnabled(true);
 }

 @Override
 public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.activity_send_photos, menu);
    return true;
 }


 @Override
 public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case android.R.id.home:
            NavUtils.navigateUpFromSameTask(this);
            return true;
    }
    return super.onOptionsItemSelected(item);
 }

 }

I would like the button in my main activity to link through to my sendphotos activity, simply opening up that activity, nothing fancy, not sending any data or anything.

I know that somewhere I need my

 Intent i = new Intent(FromActivity.this, ToActivity.class);
 startActivity(i);

but I have no idea what to replace ToActivity.class with or what else I need where.

Answer 1

You can move to desired activity on button click. just add this line.

android:onClick="sendMessage"

xml:

 <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="sendMessage"
        android:text="@string/button" />

In your main activity just add this method:

public void sendMessage(View view) {
    Intent intent = new Intent(FromActivity.this, ToActivity.class);
    startActivity(intent);
}

And the most important thing: don't forget to define your activity in manifest.xml

 <activity>
      android:name=".ToActivity"
      android:label="@string/app_name">          
 </activity>