Android Note: Scrollview

A ScrollView is a special type of FrameLayout in that it allows users to scroll through a list of views that occupy more space than the physical display.I just add some attributes Some rule for scrollview

1. Scrollview cannot hold more than one child. If you have more than one child then you must place it inside another layout like -Linear Layout, Relative Layout, Table Layout.

2. You should never use a ScrollView with a ListView or GridView, because they both takes care of their own vertical scrolling.

5. It only supports vertical scrolling not horizontal scrolling.

Syntax…

[<ScrollView>

<LinearLayout>

<TextView>

…

<\LinearLayout>

<\ScrollView> ]

Example -XML

<ScrollView

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

android:layout_width="match_parent"

android:layout_height="match_parent"

<LinearLayout

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:orientation="vertical"

<Button

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:text="button1"

android:padding="30dp"

<Button

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:text="button2"

android:padding="30dp"

<Button

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:text="button3"

android:padding="30dp"

/> <Button

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:text="button4"

android:padding="30dp"

/> <Button

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:text="button5"

android:padding="30dp"

/> <Button

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:text="button6"

android:padding="30dp"

/> <Button

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:text="button7"

android:padding="30dp"

/> <Button

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:text="button8"

android:padding="30dp"

/> <Button

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:text="button9"

android:padding="30dp"

/> <Button

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:text="button10"

android:padding="30dp"

</LinearLayout>

</ScrollView>

Programattically ScrollView

XML

<ScrollView

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

android:layout_width="match_parent"

android:layout_height="match_parent"

android:id="@+id/ll1"

</ScrollView>

Java

public class MainActivity extends AppCompatActivity {

ScrollView layout1;

ScrollView.LayoutParams params;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

layout1=(ScrollView) findViewById(R.id.ll1);

ScrollView scrollView=new ScrollView(this);

params=new ScrollView.LayoutParams(ScrollView.LayoutParams.WRAP_CONTENT,ScrollView.LayoutParams.WRAP_CONTENT);

Button button=new Button(this);

// button.setId(button);

button.setWidth(200);

button.setHeight(200);

button.setText("Program");

layout1.addView(button);

}

ScrollTo and ScrollBy

1. Scroll To - Set the scrolled position of your view.

2. Scroll By - scroll smoothly instead of immediately.

XML

<?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"

<TextView

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="hello"

<Button

android:id="@+id/scrollup"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="Scroll Up"

<Button

android:id="@+id/scrolldown"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="Scroll Down"

<Button

android:id="@+id/scrolltotop"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="Scroll To Top"

<ScrollView

android:id="@+id/myview"

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="wrap_content"

android:background="#A0A0A0"

<TextView

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:textSize="40dp"

android:text="Android is a mobile operating system (OS) currently developed by Google,

based on the Linux kernel and designed primarily for touchscreen mobile devices

such as smartphones and tablets. Android's user interface is mainly based on

direct manipulation, using touch gestures that loosely correspond to real-world actions,

such as swiping, tapping and pinching, to manipulate on-screen objects, along with a virtual keyboard for

text input. In addition to touchscreen devices, Google has further developed Android TV for televisions,

Android Auto for cars, and Android Wear for wrist watches, each with a specialized user interface.

Variants of Android are also used on notebooks, game consoles, digital cameras, and other electronics.

Android has the largest installed base of all operating systems of any kind.

Android has been the best selling OS on tablets since 2013, and on smartphones it is dominant by any metric.

Initially developed by Android, Inc., which Google bought in 2005,[16] Android was unveiled in 2007,

along with the founding of the Open Handset Alliance – a consortium of hardware, software,

and telecommunication companies devoted to advancing open standards for mobile devices.

[17] As of July 2013, the Google Play store has had over one million Android applications published,

and over 50 billion applications downloaded.[18] An April–May 2013 survey of mobile application developers found that

71% of developers create applications for Android,[19] and a 2015 survey found that 40% of

full-time professional developers see Android as their priority target platform, which is comparable to

Apple's iOS on 37% with both platforms far above others.[20] In September 2015,

Android had 1.4 billion monthly active users.[21]"

</LinearLayout>

</ScrollView>

</LinearLayout>

JAVA

public class MainActivity extends AppCompatActivity {

ScrollView layout1;

Button buttonScrollUp,buttonScrollDown,buttonScrollToTop;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

buttonScrollUp = (Button)findViewById(R.id.scrollup);

buttonScrollDown = (Button)findViewById(R.id.scrolldown);

buttonScrollToTop = (Button)findViewById(R.id.scrolltotop);

layout1 = (ScrollView)findViewById(R.id.myview);

buttonScrollUp.setOnClickListener(new Button.OnClickListener(){

@Override

public void onClick(View v) {

layout1.scrollBy(0, +20);

}});

buttonScrollDown.setOnClickListener(new Button.OnClickListener(){

@Override

public void onClick(View v) {

layout1.scrollBy(0, -20);

}});

buttonScrollToTop.setOnClickListener(new Button.OnClickListener(){

@Override

public void onClick(View v) {

layout1.scrollTo(0, 0);

}});

}

*************************************************************************

fillViewReport

Defines whether the scrollview should stretch its content to fill the viewport.

code.

It's value must be a boolean "true or false ".

android:fillViewport="true/false"

*******************************************************

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

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

android:id="@+id/scroller"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:fillViewport="true" >

<LinearLayout

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:orientation="vertical">

<TextView

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:paddingLeft="6dip"

android:paddingRight="6dip"

android:paddingTop="6dip"

android:textAppearance="?android:attr/textAppearanceMedium"

android:text="Welcome to My Application" />

<View

android:layout_width="fill_parent"

android:layout_height="1dip"

android:background="#ff106510"

android:layout_marginLeft="6dip"

android:layout_marginRight="6dip"

android:layout_marginTop="6dip"

android:layout_marginBottom="12dip" />

<TextView

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:layout_weight="1.0"

android:paddingLeft="6dip"

android:paddingRight="6dip"

android:paddingBottom="6dip"

android:text="@string/hello" />

<LinearLayout

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:background="@android:drawable/bottom_bar"

android:gravity="center_vertical">

<Button

android:layout_width="0dip"

android:layout_weight="1.0"

android:layout_height="wrap_content"

android:text="Accept" />

<Button

android:layout_width="0dip"

android:layout_weight="1.0"

android:layout_height="wrap_content"

android:text="Refuse" />

</LinearLayout>

</ScrollView>

************************************************************************

Fling

XML

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

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

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:orientation="vertical">

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_gravity="center_horizontal"

android:text="@string/hello"

android:textStyle="bold" />

<TextView

android:id="@+id/tvTap"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginTop="20dip" >

</TextView>

<TextView

android:id="@+id/tvTapEvent"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginTop="10dip" >

</TextView>

<ScrollView

android:id="@+id/scroll"

android:layout_width="fill_parent"

android:layout_height="fill_parent" >

<LinearLayout

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:orientation="vertical" >

<Button

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="Button1" />

<Button

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="Button2" />

<Button

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="Button3" />

<Button

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="Button4" />

<Button

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="Button5" />

<Button

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="Button6" />

<Button

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="Button7" />

<Button

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="Button8" />

<Button

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="Button9" />

<Button

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="Button10" />

</LinearLayout>

</ScrollView>

</LinearLayout>

java

public class MainActivity extends AppCompatActivity implements GestureDetector.OnGestureListener

{

private GestureDetector gd;

private TextView tvTap;

String TAG = getClass().getSimpleName();

private static final int SWIPE_MIN_DISTANCE = 120;

private static final int SWIPE_MAX_OFF_PATH = 250;

private static final int SWIPE_THRESHOLD_VELOCITY = 200;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

tvTap = (TextView)findViewById(R.id.tvTap);

gd = new GestureDetector(this);

gd.setOnDoubleTapListener(new GestureDetector.OnDoubleTapListener()

{

@Override

public boolean onDoubleTap(MotionEvent e)

{

return false;

}

@Override

public boolean onDoubleTapEvent(MotionEvent e)

{

return false;

}

@Override

public boolean onSingleTapConfirmed(MotionEvent e)

{

return false;

}

});

}

@Override

public boolean onTouchEvent(MotionEvent event)

{

return gd.onTouchEvent(event);//return the double tap events

}

@Override

public boolean onDown(MotionEvent e)

{

return false;

}

@Override

public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY)

{

try {

if (Math.abs(e1.getY() - e2.getY()) > SWIPE_MAX_OFF_PATH)

{

return false;

}

if(e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {

tvTap.setText("Flip Right to Left");

Log.v(TAG, "Right to Left");

} else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {

tvTap.setText("Flip Left to Right");

Log.v(TAG, "Left to Right");

}

} catch (Exception e)

{

}

return false;

}

@Override

public void onLongPress(MotionEvent e)

{

}

@Override

public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY)

{

return false;

}

@Override

public void onShowPress(MotionEvent e)

@Override

public boolean onSingleTapUp(MotionEvent e)

{

return false;

}

Full Scroll ( focus - Up ,Down)

Handles scrolling in response to a "home/end" shortcut press. This method will scroll the view to the top or bottom and give the focus to the topmost/bottommost component in the new visible area. If no component is a good candidate for focus, this scrollview reclaims the focus.

XML

<?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"

<ScrollView

android:id="@+id/myview"

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="wrap_content"

android:background="#A0A0A0"

<TextView

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:textSize="40dp"

android:text="Android is a mobile operating system (OS) currently developed by Google, based on the Linux kernel and designed primarily for touch screen mobile devices such as smart phones and tablets. Android's user interface is mainly based on

direct manipulation, using touch gestures that loosely correspond to real-world actions, such as swiping, tapping and pinching, to manipulate on-screen objects, along with a virtual keyboard for text input. In addition to touch screen devices, Google has further developed Android TV for televisions, Android Auto for cars, and Android Wear for wrist watches, each with a specialized user interface. Variants of Android are also used on notebooks, game consoles, digital cameras, and other electronics. Android has the largest installed base of all operating systems of any kind.

Android has been the best selling OS on tablets since 2013, and on smartphones it is dominant by any metric. Initially developed by Android, Inc., which Google bought in 2005,[16] Android was unveiled in 2007, along with the founding of the Open Handset Alliance – a consortium of hardware, software, and telecommunication companies devoted to advancing open standards for mobile devices. [17] As of July 2013, the Google Play store has had over one million Android applications published, and over 50 billion applications downloaded.[18] An April–May 2013 survey of mobile application developers found that 71% of developers create applications for Android,[19] and a 2015 survey found that 40% of full-time professional developers see Android as their priority target platform, which is comparable toApple's iOS on 37% with both platforms far above others.[20] In September 2015,Android had 1.4 billion monthly active users.[21]"

</LinearLayout>

</ScrollView>

</LinearLayout>

Java

public class MainActivity extends AppCompatActivity {

ScrollView mScrollView;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

mScrollView = (ScrollView) findViewById(R.id.myview);

mScrollView.post(new Runnable() {

@Override

public void run() {

mScrollView.fullScroll(ScrollView.FOCUS_DOWN);

}

});

}

Android Note

Wednesday 17 August 2016

Scrollview

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