CODEWITHSUNDEEP
javaandroidxmltextviewscrollview
SingleWave Games
SingleWave Games

Reputation: 2648

Android - ScrollView with TextView auto scrolling

I have a TextView within a ScrollView, which currently scrolls to the bottom of the TextView.

The TextView is filled dynamically constantly updating (the TextView is essentially acting as an actions console).

However, the problem I am having is that when the dynamic text is added to the ScrollView, the user can scroll past the text into black space, which is increasing everytime more content is added to the TextView.

I have tried various different apporaches however none of these gave the right outcome. I cannot use maxLines or define height of the layouts as I need this to be dynamic for the various screen sizes, which the number of lines visible constantly changing.

I had also orginally done this progromatically, however this was crashing at random time and therefore would like to keep it in my layout (better usabilty), example code below:

final int scrollAmount = update.getLayout().getLineTop(update.getLineCount()) - update.getHeight();
if(scrollAmount > 0)
{
    update.scrollTo(0, scrollAmount);
}

The code below is my current layout xml being used to automatically scroll my TextView to the bottom as content is added:

<ScrollView
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_above="@+id/spacer2"
    android:layout_below="@+id/spacer1"
    android:fillViewport="true" >
    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical" >
        <TextView
            android:id="@+id/battle_details"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:textSize="12dp"
            android:layout_gravity="bottom" />
    </LinearLayout>
</ScrollView>

enter image description here

EDIT - This is the code I am using to add text to my TextView:

private void CreateConsoleString()
{
    TextView update = (TextView)findViewById(R.id.battle_details);
    String ConsoleString = "";
    // BattleConsole is an ArrayList<String>
    for(int i = 0; i < BattleConsole.size(); i++)
    {
        ConsoleString += BattleConsole.get(i) + "\n";
    }
    update.setText(ConsoleString);
}

EDIT 2 - I add content to the BattleConsole like this:

BattleConsole.add("Some console text was added");
CreateConsoleString();

To sum up my only issue is the ScrollView and/or TextView is adding blank space to the bottom rather than stop the user from scrolling at the last line of text. Any help or guidence as to where I am going wrong would be much appreciated.

Upvotes: 1

Views: 5657

Answers (1)

Adam Arold
Adam Arold

Reputation: 30528

It looks like that when you call

BattleConsole.get(i)

it sometimes returns an empty String so you are just basically adding new lines to your TextView.

You can do this for example:

StringBuilder consoleString = new StringBuilder();
// I'm using a StringBuilder here to avoid creating a lot of `String` objects
for(String element : BattleConsole) {
    // I'm assuming element is not null
    if(!"".equals(element)) {
        consoleString.append(element);
        consoleString.append(System.getProperty("line.separator")); // I'm using a constant here.
    }
}
update.setText(consoleString.toString());

If you could post the code of BattleConsole I could help you more.

As a footnote: it is encouraged to use camelCase in java. Only class names start with capital letters in java according to the convention.

Upvotes: 1

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