Android - i can not set EditText layout width programmatically

Question

i tried two way to set width of the EditText, but i got no proper result. the xml file contains:

<TextView
    android:id="@+id/textView1"
    style="@android:style/Widget.AutoCompleteTextView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:gravity="center"
    android:hint="@string/classname"
    android:textSize="25sp" />

<TextView
    android:id="@+id/textView2"
    style="@android:style/Widget.AutoCompleteTextView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:gravity="center"
    android:hint="@string/teacher"
    android:textSize="25sp" />

the first way:

TextView tw1 = (TextView) findViewById(R.id.textView1);
TextView tw2 = (TextView) findViewById(R.id.textView2);
tw2.setLayoutParams(new LinearLayout.LayoutParams(tw1.getLayoutParams().width, LinearLayout.LayoutParams.WRAP_CONTENT));

the second way:

TextView tw1 = (TextView) findViewById(R.id.textView1);
TextView tw2 = (TextView) findViewById(R.id.textView2);
tw2.setWidth(tw1.getWidth());

While the first code does not work at all, the second code gives an unrelated result. What is my mistake or what is the correct way of doing this?

Answer 1

As @Amin said, layout width was zero when using getWidth in the onCreate or onStart or onResume methods. I found the solution like that:

tw1.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                tw1.getViewTreeObserver().removeOnGlobalLayoutListener(this);
                int theWidth = tw1.getWidth();
                tw2.setWidth(theWidth);
            }
        });

This method is called when the view object's properties change. For this problem it is a good solution i think.