rflexor rflexor - 2 months ago 18
Android Question

Programmatically scrolling an EditText

I'm writing a simple caesar-encryption-activity. Two EditTexts on screen, one clear-text, one crypted. Here's an example for the crypted EditText - the cleartext one is similar.

<EditText
android:layout_below="@id/Caesar_Label_CryptText"
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:id="@+id/Caesar_Text_CryptText"
android:hint="Enter crypted text"
android:maxLines="2"
android:lines="2"
android:minLines="2"
android:inputType="text|textMultiLine|textVisiblePassword"
android:scrollbars="vertical"
android:gravity="top" />


Now when entering cleartext I have an TextChangedListener running that programatically crypts and fills that crypto-EditText. So far, so good.

When the cleartext entered gets really long, the cleartext-EditText scrolls with my imput, but the crypto-EditText stays at the top of the text. I'd really like the crypto-EditText to scroll so that it always shows the bottom line of its content.

How can that be done, preferably from the onTextChanged()-Method of the TextWatcher?

Answer Source

Ok, found it. It was the cursor (called Selection on EditText and TextViews).

This is how I got it to work:

ivClear    // assigned the EditText that has the input
ivCrypt    // assigned the target EditText, that I want to scroll
aText      // the input from ivClear, crypted

Then use:

    ivCrypt.setText(aText);                               // assign the Text
    ivCrypt.setSelection(ivClear.getSelectionStart());    // scroll

Phew, finally :) Always underestimated the power of the Spannable ;)