Android Relative Layout: Button Layout params conflict

Issue

I'm trying to make my first Android Calculator, the first code I wrote resulted in a calculator of small buttons, which don't re-size according to the screen size.

I have searched in the Internet and found some ways to do it, and here's the part of the code responsible for that - I have 20 buttons, numbered from 0 to 19 -

@SuppressLint("NewApi")
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_welcome);
    Display display = getWindowManager().getDefaultDisplay();
    Point size = new Point();
    int width,height;
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB_MR2)
    {
        WindowManager w = getWindowManager();
        w.getDefaultDisplay().getSize(size);
        width = size.x;
        height = size.y;
    }
    else
    {
        width = display.getWidth();
        height = display.getHeight();
    }
    Button b;
    TextView text1 = (TextView)findViewById(R.id.screen);
    text1.setWidth(width);
    width/=6;
    height/=7;
    text1.setHeight(height);
    for (int i=0;i<20;i++)
    {
        String ButtonName = "button"+i;
        int ButtonId = getResources().getIdentifier(ButtonName, "id", "calculator.essam.net");
        b = (Button)findViewById(ButtonId);
        RelativeLayout.LayoutParams par = new RelativeLayout.LayoutParams(b.getLayoutParams());
par.width = width;
par.height = height;
        b.setLayoutParams(par);
    }
}

In the XML File, listed are my button layout rules, such as toLeftOf, toRightOf, above, below, alignParentTop, alignParentLeft, alignParentRight, and alignParentBottom.

<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"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".WelcomeActivity" >


<TextView
    android:id="@+id/screen"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_alignParentTop="true"
    android:text="" />

<Button
    android:id="@+id/button0"

    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@+id/button18"
    android:layout_alignParentLeft="true"
    android:minHeight="0dp"
    android:minWidth="0dp"
    android:onClick="click"
    android:tag="0"
    android:text="@string/number0" />

<Button
    android:id="@+id/button1"

    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@+id/button0"
    android:layout_alignParentLeft="true"
    android:layout_below="@+id/button4"
    android:minHeight="0dp"
    android:minWidth="0dp"
    android:onClick="click"
    android:tag="1"
    android:text="@string/number1" />

<Button
    android:id="@+id/button2"

    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@+id/button10"
    android:layout_below="@+id/button5"
    android:layout_toLeftOf="@+id/button3"
    android:layout_toRightOf="@+id/button1"
    android:minHeight="0dp"
    android:minWidth="0dp"
    android:onClick="click"
    android:tag="2"
    android:text="@string/number2" />

<Button
    android:id="@+id/button3"

    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@+id/button15"
    android:layout_below="@+id/button6"
    android:layout_toLeftOf="@+id/button13"
    android:minHeight="0dp"
    android:minWidth="0dp"
    android:onClick="click"
    android:tag="3"
    android:text="@string/number3" />

<Button
    android:id="@+id/button4"

    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_below="@+id/button7"
    android:layout_toLeftOf="@+id/button5"
    android:minHeight="0dp"
    android:minWidth="0dp"
    android:onClick="click"
    android:tag="4"
    android:text="@string/number4" />

<Button
    android:id="@+id/button5"

    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@+id/button8"
    android:layout_toLeftOf="@+id/button6"
    android:minHeight="0dp"
    android:minWidth="0dp"
    android:onClick="click"
    android:tag="5"
    android:text="@string/number5" />

<Button
    android:id="@+id/button6"

    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@+id/button9"
    android:layout_toLeftOf="@+id/button12"
    android:minHeight="0dp"
    android:minWidth="0dp"
    android:onClick="click"
    android:tag="6"
    android:text="@string/number6" />

<Button
    android:id="@+id/button7"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_below="@+id/screen"
    android:layout_toLeftOf="@+id/button8"
    android:minHeight="0dp"
    android:minWidth="0dp"
    android:onClick="click"
    android:tag="7"
    android:text="@string/number7" />

<Button
    android:id="@+id/button8"

    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@+id/screen"
    android:layout_toLeftOf="@+id/button9"
    android:minHeight="0dp"
    android:minWidth="0dp"
    android:onClick="click"
    android:tag="8"
    android:text="@string/number8" />

<Button
    android:id="@+id/button9"

    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@+id/screen"
    android:layout_toLeftOf="@+id/button11"
    android:minHeight="0dp"
    android:minWidth="0dp"
    android:onClick="click"
    android:tag="9"
    android:text="@string/number9" />

<Button
    android:id="@+id/button10"

    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@+id/button19"
    android:layout_toRightOf="@+id/button0"
    android:minHeight="0dp"
    android:minWidth="0dp"
    android:onClick="click"
    android:tag="."
    android:text="@string/dot" />

<Button
    android:id="@+id/button11"

    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@+id/button12"
    android:layout_alignParentRight="true"
    android:layout_below="@+id/screen"
    android:minHeight="0dp"
    android:minWidth="0dp"
    android:onClick="click"
    android:tag="+"
    android:text="@string/signPlus" />

<Button
    android:id="@+id/button12"

    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@+id/button13"
    android:layout_alignParentRight="true"
    android:minHeight="0dp"
    android:minWidth="0dp"
    android:onClick="click"
    android:tag="-"
    android:text="@string/signMinus" />

<Button
    android:id="@+id/button13"

    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@+id/button14"
    android:layout_alignParentRight="true"
    android:minHeight="0dp"
    android:minWidth="0dp"
    android:onClick="click"
    android:tag="*"
    android:text="@string/signTimes" />

<Button
    android:id="@+id/button14"

    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@+id/button17"
    android:layout_alignParentRight="true"
    android:layout_toRightOf="@+id/button15"
    android:minHeight="0dp"
    android:minWidth="0dp"
    android:onClick="click"
    android:tag="/"
    android:text="@string/signDivide" />

<Button
    android:id="@+id/button15"

    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@+id/button16"
    android:layout_toRightOf="@+id/button10"
    android:minHeight="0dp"
    android:minWidth="0dp"
    android:onClick="click"
    android:tag="="
    android:text="@string/signEquals" />

<Button
    android:id="@+id/button16"

    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_toLeftOf="@+id/button17"
    android:layout_toRightOf="@+id/button19"
    android:minHeight="0dp"
    android:minWidth="0dp"
    android:onClick="click"
    android:tag="("
    android:text="@string/openBracket" />

<Button
    android:id="@+id/button17"

    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_alignParentRight="true"
    android:minHeight="0dp"
    android:minWidth="0dp"
    android:onClick="click"
    android:tag=")"
    android:text="@string/closedBracket" />

<Button
    android:id="@+id/button18"

    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_alignParentLeft="true"
    android:minHeight="0dp"
    android:minWidth="0dp"
    android:onClick="click"
    android:tag="CLR"
    android:text="@string/clear"
    android:textSize="12sp" />

<Button
    android:id="@+id/button19"

    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_toRightOf="@+id/button18"
    android:minHeight="0dp"
    android:minWidth="0dp"
    android:onClick="click"
    android:tag="DEL"
    android:text="@string/backSpace"
    android:textSize="12sp" />

</RelativeLayout>

The problem is when I use RelativeLayout.LayoutParams All my layout rules are overwritten, and when I use button.setWidth() and button.setHeight(), the layout rules are kept the same, but the size doesn't change.

Solution

You should set width and height on existing layout params and not replace it with a new one. You can access the layout params created during layout inflation with getLayoutParams(). That is, replace

RelativeLayout.LayoutParams par = new RelativeLayout.LayoutParams(b.getLayoutParams());

with

RelativeLayout.LayoutParams par = b.getLayoutParams();

However, I suggest you forget about this kind of layout and learn to use LinearLayout layout_weight mechanism to make view sizes relative to available space.

Answered By - laalto