如何获得可扩展的textview宽度以将其修剪长度设置为1行

Question

i'm using expandable textview to display some part of the text and when user clicks on this textview then user can see whole String of that text for that i'm using this example but the problem is the trim length of the expandable textview its set to fixed, but i want to set the trim length dynamic based on screen size with only one line, when i use trim_length = 200 the text displayed is of 3 lines, here is my code...

ExpandableTextView.java

public class ExpandableTextView extends TextView {
    private static final int DEFAULT_TRIM_LENGTH = 200;
    private static final String ELLIPSIS = ".....";

    private CharSequence originalText;
    private CharSequence trimmedText;
    private BufferType bufferType;
    private boolean trim = true;
    private int trimLength;

    public ExpandableTextView(Context context) {
        this(context, null);
    }

    public ExpandableTextView(Context context, AttributeSet attrs) {
        super(context, attrs);

        TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.ExpandableTextView);
        this.trimLength = typedArray.getInt(R.styleable.ExpandableTextView_trimLength, DEFAULT_TRIM_LENGTH);
        typedArray.recycle();

        setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                trim = !trim;
                setText();
                requestFocusFromTouch();
            }
        });
    }

    private void setText() {
        super.setText(getDisplayableText(), bufferType);
    }

    private CharSequence getDisplayableText() {
        return trim ? trimmedText : originalText;
    }

    @Override
    public void setText(CharSequence text, BufferType type) {
        originalText = text;
        trimmedText = getTrimmedText(text);
        bufferType = type;
        setText();
    }

    private CharSequence getTrimmedText(CharSequence text) {
        if (originalText != null && originalText.length() > trimLength) {
            return new SpannableStringBuilder(originalText, 0, trimLength + 1).append(ELLIPSIS);
        } else {
            return originalText;
        }
    }

    public CharSequence getOriginalText() {
        return originalText;
    }

    public void setTrimLength(int trimLength) {
        this.trimLength = trimLength;
        trimmedText = getTrimmedText(originalText);
        setText();
    }

    public int getTrimLength() {
        return trimLength;
    }
}

ExpandableTextView expandableTextView = (ExpandableTextView) findViewById(R.id.lorem_ipsum); expandableTextView.setText(yourText);

Answer 1

you can do it like this

public class ExpandableTextView extends TextView
{
    // copy off TextView.LINES
    private static final int MAXMODE_LINES = 1;
//    private OnExpandListener onExpandListener;
    private final int maxLines;
    private boolean expanded;


    public ExpandableTextView(final Context context)
    {
        this(context, null);
    }

    public ExpandableTextView(final Context context, final AttributeSet attrs)
    {
        this(context, attrs, 0);
    }

    public ExpandableTextView(final Context context, final AttributeSet attrs, final int defStyle)
    {
        super(context, attrs, defStyle);

        // read attributes
        final TypedArray attributes = context.obtainStyledAttributes(attrs, R.styleable.ExpandableTextView, defStyle, 0);
//        this.animationDuration = attributes.getInt(R.styleable.ExpandableTextView_trimLength, 200);
        attributes.recycle();

        // keep the original value of maxLines
        this.maxLines = this.getMaxLines();


    }

    @Override
    public int getMaxLines()
    {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN)
        {
            return super.getMaxLines();
        }

        try
        {
            final Field mMaxMode = TextView.class.getField("mMaxMode");
            mMaxMode.setAccessible(true);
            final Field mMaximum = TextView.class.getField("mMaximum");
            mMaximum.setAccessible(true);

            final int mMaxModeValue = (int) mMaxMode.get(this);
            final int mMaximumValue = (int) mMaximum.get(this);

            return mMaxModeValue == MAXMODE_LINES ? mMaximumValue : -1;
        }
        catch (final Exception e)
        {
            return -1;
        }
    }

    public boolean toggle()
    {
        return this.expanded
                ? this.collapse()
                : this.expand();
    }


    public boolean expand()
    {
        if (!this.expanded && this.maxLines >= 0)
        {

            // set maxLines to MAX Integer, so we can calculate the expanded height
            this.setMaxLines(Integer.MAX_VALUE);


            // keep track of current status
            ExpandableTextView.this.expanded = true;


            return true;
        }

        return false;
    }


    public boolean collapse()
    {
        if (this.expanded && this.maxLines >= 0)
        {  

            ExpandableTextView.this.setMaxLines(ExpandableTextView.this.maxLines);
            // keep track of current status
            ExpandableTextView.this.expanded = false;


            return true;
        }

        return false;
    }
}

activity.xml

<com.yourpackagename.ExpandableTextView
            android:id="@+id/expandableTextView"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:ellipsize="end"
            android:maxLines="1"
     />

activity.java

ExpandableTextView expandableTextView = (ExpandableTextView) this.findViewById(R.id.expandableTextView);
expandableTextView.setOnClickListener(new View.OnClickListener()
        {
            @SuppressWarnings("ConstantConditions")
            @Override
            public void onClick(final View v)
            {
                expandableTextView.toggle();
            }
        });