didi/DoKit · error · IllegalArgumentException

Target must not be null.

Error message

Target must not be null.

What it means

Thrown by RequestCreator.into(Target) when the Target argument is null. A Target receives the loaded bitmap callbacks, so a null target has nothing to deliver to; Picasso validates on the main thread (checkMain runs first) and throws IllegalArgumentException.

Source

Thrown at Android/dokit/src/main/java/com/didichuxing/doraemonkit/picasso/RequestCreator.java:518

     *     frame.setBackgroundResource(R.drawable.profile_error);
     *   }
     *
     *   {@literal @}Override public void onPrepareLoad(Drawable placeHolderDrawable) {
     *     frame.setBackgroundDrawable(placeHolderDrawable);
     *   }
     * }
     * </pre></blockquote>
     * <p>
     * <em>Note:</em> This method keeps a weak reference to the {@link Target} instance and will be
     * garbage collected if you do not keep a strong reference to it. To receive callbacks when an
     * image is loaded use {@link #into(android.widget.ImageView, Callback)}.
     */
    public void into(Target target) {
        long started = System.nanoTime();
        checkMain();

        if (target == null) {
            throw new IllegalArgumentException("Target must not be null.");
        }
        if (deferred) {
            throw new IllegalStateException("Fit cannot be used with a Target.");
        }

        if (!data.hasImage()) {
            picasso.cancelRequest(target);
            target.onPrepareLoad(setPlaceholder ? getPlaceholderDrawable() : null);
            return;
        }

        Request request = createRequest(started);
        String requestKey = createKey(request);

        if (shouldReadFromMemoryCache(memoryPolicy)) {
            Bitmap bitmap = picasso.quickMemoryCacheCheck(requestKey);
            if (bitmap != null) {
                picasso.cancelRequest(target);

View on GitHub (pinned to 626827cddb)

Solutions

1. Pass a non-null Target implementation and keep a strong reference to it (into(Target) holds only a weak reference)
2. If the target is optional by the time the call runs, guard: if (target != null) rc.into(target); else rc.fetch(null);
3. Initialize the Target field before building the request chain

Example fix

// before
private Target target; // not yet assigned
picasso.load(url).into(target); // throws "Target must not be null."

// after
target = new Target() { /* onBitmapLoaded/onBitmapFailed */ };
picasso.load(url).into(target);

if (target != null) {
    picasso.load(url).into(target);
} else {
    picasso.load(url).fetch(null); // warm cache instead
}

static boolean isUsableTarget(Target t) {
    return t != null;
}

When it happens

Trigger: Calling .into((Target) null), or passing a Target field that was not yet initialized / was nulled after a lifecycle event.

Common situations: Fields like custom Target instances referenced before initialization in onCreate; passing a weakly-held Target that was garbage-collected and left null; Kotlin nullable Target passed without !!-style checks.

Related errors

• Error image may not be null.
• Tag invalid.
• Memory policy cannot be null.
• Network policy cannot be null.
• Fit cannot be used with a Target.

AI-assisted analysis of didi/DoKit@626827cddb (2026-08-14). Data as JSON: /api/errors/b96858042b9a3249. Report an issue: GitHub.