CODEWITHSUNDEEP
javac#androidviewpixel
MOckjer
MOckjer

Reputation: 621

What units are applied when declaring a view programmatically?

When adding a view in an axml file, it is possible to simply specify the size and the units of the view's attribute, for example:

<TextView
    android:TextSize = "10sp"
    android:layout_marginTop = "10dp" />

As said in this answer, there are specific units for specific purposes.

My main question is, when applying a size programmatically (by code) in a dynamic way, what are the units applied for the size?

For example, when declaring a TextSize like this:

TextView tv = new TextView();
tv.TextSize = 10;

What are the units applied for the text size? sp? dp? px?

And most importantly, how can I change them to fit my needs?

Upvotes: 4

Views: 667

Answers (2)

Arpit bandil
Arpit bandil

Reputation: 204

Hi @Daniel if u programmatically generate textview as following code

TextView tv = new TextView();
tv.setTextSize(10); // Sets text in sp (Scaled Pixel).

And if you want to set text size with other unit so you can achieved by following way.

TextView tv = new TextView();
tv.setTextSize(TypedValue.COMPLEX_UNIT_PX, 10); // Sets text in px (Pixel).
tv.setTextSize(TypedValue.COMPLEX_UNIT_DIP, 10); // Sets text in dip (Device Independent Pixels).
tv.setTextSize(TypedValue.COMPLEX_UNIT_SP, 10); // Sets text in sp (Scaled Pixel).
tv.setTextSize(TypedValue.COMPLEX_UNIT_PT, 10); // Sets text in pt (Points).
tv.setTextSize(TypedValue.COMPLEX_UNIT_IN, 10); // Sets text in in (inches).
tv.setTextSize(TypedValue.COMPLEX_UNIT_MM, 10); // Sets text in mm (millimeters).

By default Android uses "sp" for text size and "px" for view size.

For other View sizes we can set in px(pixels) but if you want customize the unit you can use custom methods

/**
     * Converts dip to px.
     *
     * @param context -  Context of calling class.
     * @param dip     - Value in dip to convert.
     * @return - Converted px value.
     */
    public static int convertDipToPixels(Context context, int dip) {
        if (context == null)
            return 0;
        Resources resources = context.getResources();
        float px = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dip, resources.getDisplayMetrics());
        return (int) px;
    }

From above method you can convert YOUR_DESIRED_UNIT in pixels and then set to view. You can replace

TypedValue.COMPLEX_UNIT_DIP

with above unit as per you use case. You can also use it vice-versa for px to dip but we cant assign to custom unit to view so that's why i am using it like this.

I hope i explained well this.

Upvotes: 4

milad salimi
milad salimi

Reputation: 1660

First:

I think you should avoid from set size programmatically as much as possible.

Second:

px Pixels : corresponds to actual pixels on the screen.

dp or dip Density-independent Pixels- : an abstract unit that is based on the physical density of the screen. These units are relative to a 160 dpi screen, so one dp is one pixel on a 160 dpi screen

sp Scale-independent Pixels- : this is like the dp unit, but it is also scaled by the user's font size preference

And in your third question , i think :

for example :

for a edittext you should not use constant for width like this :

  <TextView
        android:layout_width="100dp"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:text="@string/banklist_firstselectbank"
        style="@style/TextAppearanceHeadline2"
        android:gravity="center"/>

I think its better to use margin start and margin end like this :

 <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:text="@string/banklist_firstselectbank"
        style="@style/TextAppearanceHeadline2"
        android:layout_marginEnd="50dp"
        android:layout_marginStart="50dp"
        android:gravity="center"
        />

And use as much as possible fields like : gravity and other instead of constant number.

Upvotes: 2

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