How to open a second activity on click of button i

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 android:onClick="sendMessage"this line.

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>

Answer 2

Button btn = (Button) findViewById(R.id.button1);

btn.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        Intent myIntent = new Intent(MainActivity.this, MainActivity2.class);
        MainActivity.this.startActivity(myIntent);       
    }  
});

The answer for the complete noob from a complete noob: MainActivity is the name of the first activity. MainActivity2 is the name of the second activity. button1 is the I.D of the button in xml for MainActivity Activity.

Answer 3

Replace the below line code:

import android.view.View.OnClickListener;
public class MainActivity extends Activity implements OnClickListener{
   Button button;
    @Override
     public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        button=(Button)findViewById(R.id.button1);
        button.setOnClickListener(this);
      }
       public void onClick(View v) {
        if(v.getId==R.id.button1){
      Intent i = new Intent(FromActivity.this, ToActivity.class);
               startActivity(i);
            }
        }
     }

Add the below lines in your manifest file:

   <activity android:name="com.packagename.FromActivity"></activity>
   <activity android:name="com.packagename.ToActivity"></activity>

Answer 4

This always works, either one should be just fine:

@Override
public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);

    Button btn = (Button) findViewById(R.id.button1);
    btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick (View v) {
            startActivity(new Intent("com.tobidae.Activity1"));
        }
        //** OR you can just use the one down here instead, both work either way
        @Override
        public void onClick (View v){
            Intent i = new Intent(getApplicationContext(), ChemistryActivity.class);
            startActivity(i);
        }
    }
}

Answer 5

 <Button
            android:id="@+id/btnSignIn"
            android:layout_width="250dp"
            android:layout_height="40dp"
            android:layout_marginEnd="8dp"
            android:layout_marginLeft="8dp"
            android:layout_marginRight="8dp"
            android:layout_marginStart="8dp"
            android:layout_marginTop="16dp"
            android:background="@drawable/circal"
            android:text="Sign in"
            android:textColor="@color/white"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/etPasswordLogin" />

IN JAVA CODE

Button signIn= (Button) findViewById(R.id.btnSignIn);

signIn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startActivity(new Intent(SignInPage.this,MainActivity.class));
            }
        });

}

Answer 6

From Activity : where you are currently ?

To Activity : where you want to go ?

Intent i = new Intent( MainActivity.this, SendPhotos.class); startActivity(i);

Both Activity must be included in manifest file otherwise it will not found the class file and throw Force close.

Edit your Mainactivity.java

crate button's object;

now Write code for click event.

        Button btn = (button)findViewById(R.id.button1);
         btn.LoginButton.setOnClickListener(new View.OnClickListener() 
       {

                @Override
                public void onClick(View v) 
                {
                 //put your intent code here
                }
   });

Hope it will work for you.