PhilJay/MPAndroidChart · error · IllegalArgumentException

entries array is NULL

Error message

entries array is NULL

What it means

Thrown by the Legend(LegendEntry[]) constructor when a null array is passed. The constructor delegates to this() then validates entries == null and rejects it with IllegalArgumentException, because a legend cannot be built from a missing entry set. This is the standard precondition for explicitly constructing a legend with custom entries.

Source

Thrown at MPChartLib/src/main/java/com/github/mikephil/charting/components/Legend.java:164

     * default constructor
     */
    public Legend() {

        this.mTextSize = Utils.convertDpToPixel(10f);
        this.mXOffset = Utils.convertDpToPixel(5f);
        this.mYOffset = Utils.convertDpToPixel(3f); // 2
    }

    /**
     * Constructor. Provide entries for the legend.
     *
     * @param entries
     */
    public Legend(LegendEntry[] entries) {
        this();

        if (entries == null) {
            throw new IllegalArgumentException("entries array is NULL");
        }

        this.mEntries = entries;
    }

    /**
     * This method sets the automatically computed colors for the legend. Use setCustom(...) to set custom colors.
     *
     * @param entries
     */
    public void setEntries(List<LegendEntry> entries) {
        mEntries = entries.toArray(new LegendEntry[entries.size()]);
    }

    public LegendEntry[] getEntries() {
        return mEntries;
    }

View on GitHub (pinned to 9c7275a059)

Solutions

1. Pass a non-null LegendEntry[] (an empty array is acceptable; null is not).
2. Guard: if (entries != null) chart.getLegend().setCustom(entries); else use chart.getLegend().setEntries(Collections.emptyList()).
3. Initialize the array before constructing the Legend: LegendEntry[] entries = buildEntries(); chart.getLegend().setCustom(entries).
4. Prefer setEntries(List) or setCustom(...) which accept lists and handle emptiness more gracefully.

Example fix

// before
Legend legend = new Legend(null); // throws

// after
LegendEntry[] entries = new LegendEntry[0]; // or real entries
Legend legend = new Legend(entries);
// or use the existing chart legend:
chart.getLegend().setCustom(entries);

if (entries != null) {
    Legend legend = new Legend(entries);
} else {
    throw new IllegalStateException("Legend entries must not be null");
}

boolean isValidEntries(LegendEntry[] e) {
    return e != null;
}

When it happens

Trigger: Calling new Legend((LegendEntry[]) null). Passing a computed array that resolved to null (e.g. entries not yet initialized). Splitting legend setup so the array is built lazily but the constructor runs first.

Common situations: Building a custom legend before the data set list is populated; deserializing legend entries where the source list was empty/missing and toArray produced null; refactoring that passes a field not yet assigned.

Related errors

• Object Pool must be instantiated with a capacity greater tha
• BarData needs to hold at least 2 BarDataSets to allow groupi

AI-assisted analysis of PhilJay/MPAndroidChart@9c7275a059 (2026-08-14). Data as JSON: /api/errors/cbd181d48bfa925c. Report an issue: GitHub.