Android Button

From Developer.android.com: "A button consists of text or an icon (or both text and an icon) that communicates what action occurs when the user touches it."

In this tutorial, we show you how to display a custom button with image, add a click listener by a few different ways, when user click on the button, open an URL in your Android’s internet browser.

Just open Eclipse and this is what you see after you drag a button to your layout.

Demo:

1. Two ways to make a button:

1.1 Design in your XML layout: 

 <Button

        android:id="@+id/button1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:background="@drawable/button_bg"

        android:onClick="button_click"

        />

We need file layout "button_bg.xml" in drawable folder to customize this button

File: “res/drawable/button_bg.xml” 

<?xml version="1.0" encoding="utf-8"?>

<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:drawable="@drawable/up_button_press"

          android:state_pressed="true" />

    <item android:drawable="@drawable/up_button" />

</selector>

up_button.png

up_button_press.png 

1.2. By java code

If we before have a layout like:

<?xml version="1.0" encoding="utf-8"?>

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

        android:orientation="vertical"

        android:layout_width="fill_parent"

        android:layout_height="fill_parent"

        >

        <LinearLayout

            android:orientation="vertical"

            android:layout_width="fill_parent"

            android:layout_height="fill_parent"

            android:id="@+id/layoutId"

            >

        </LinearLayout>

</LinearLayout>

Now the code we use to add button dynamically to this layout:

Button myButton = new Button(this);

// sets button properties

myButton.setText("Dynamic Button");

// btn.setId(1200);// use it if you want to set id for this button

myButton.setBackgroundResource(R.drawable.button_bg);

// retrieve a reference to the container layout

LinearLayout container = (LinearLayout)findViewById(R.id.layoutId);

LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);

// adds dynamic button to the GUI

container.addView(myButton,lp);

2. Two ways to attach a click listener to the button, when user click on the button, open an URL in your Android’s internet browser

2.1. Use  android:onClick attribute in your button XML definition:

     android:onClick="button_click"

And in your code define the method button_click:

public void button_click(View view){ 

   Intent browserIntent =

             new Intent(Intent.ACTION_VIEW, Uri.parse("http://custom-android-dn.blogspot.com/"));

       startActivity(browserIntent);

}

2.2. Using an OnClickListener

myButton.setOnClickListener(new OnClickListener() {

@Override

   public void onClick(View v) {

      Intent browserIntent =

      new Intent(Intent.ACTION_VIEW, Uri.parse("http://custom-android-                 dn.blogspot.com/"));

      startActivity(browserIntent);

      }

});

CUSTOMIZED BUTTON

If you want to costumize your button using selector, you can find in the link below:

• Android Button Set 1
• Android Button Set 2

Adding Text & Image to Button

Code:

<Button
                android:id="@+id/preview"
                android:layout_width="fill_parent"
                android:layout_height="50dp"
                android:textStyle="bold"
                android:textSize="18sp"
                android:gravity="center_horizontal"
                android:shadowColor="#000000"
                android:shadowDx="1"
                android:shadowDy="1"
                android:shadowRadius="0.6"
                android:drawableLeft="@drawable/ic_preview"
                android:padding="10dp"
                android:background="@drawable/btn_style2"
                android:text="Preview"
                android:textColor="#FFFFFF" />

Demo:

That's all for now, Happy Coding!