Android新手求助：无错误行号的IndexOutOfBoundsException问题

Hey there! That crash you're seeing—IndexOutOfBoundsException pointing to Paint.getRunAdvance—is a text rendering issue, usually tied to how you're setting content on your buttons or a mismatch in your data setup. Let's walk through how to fix this while keeping your current implementation intact.

First, Let's Diagnose the Possible Culprits #

Looking at your code and stack trace, a few things stand out:

• Hardcoded TotalChapters: You've set this to 2, which matches your current array lengths, but it's risky if you ever update your string arrays later.
• Split text setting: Using setText() followed by append() with Html.fromHtml() might be creating a text structure that causes rendering glitches under the hood.
• Font loading risk: If your custom font file isn't properly loaded, it could throw off text measurement and lead to this crash.

Step-by-Step Fixes #

1. Replace Hardcoded Chapter Count with Dynamic Array Length

Instead of forcing TotalChapters = 2, pull the length directly from your string arrays to ensure they always match. This prevents future mismatches if you add more chapters:

// Remove the hardcoded int TotalChapters = 2;
private void initializeData() {
    ChapterName = getResources().getStringArray(R.array.ChapterName);
    ChapterNumber = getResources().getStringArray(R.array.ChapterNumber);
    
    // Add a check to make sure both arrays are the same length
    if (ChapterNumber.length != ChapterName.length) {
        Log.e("CategoryList", "Error: ChapterNumber and ChapterName arrays have different lengths!");
        return;
    }
    TotalChapters = ChapterNumber.length; // Use the actual array length
    
    // Rest of your code...
}

2. Set Button Text in One Go (Avoid append())

Combining your text into a single HTML string and setting it all at once avoids potential text structure issues that cause rendering crashes. Replace your current button text lines with this:

// Replace these two lines:
// ChapterButton[start].setText(ChapterNumber[start]);
// ChapterButton[start].append(Html.fromHtml("<br/>" + ChapterName[start]));

// Use a single HTML string instead
String buttonText = String.format("%s<br/>%s", ChapterNumber[start], ChapterName[start]);
// For Android 7.0+, use Html.FROM_HTML_MODE_LEGACY to avoid deprecation warnings
ChapterButton[start].setText(Html.fromHtml(buttonText, Html.FROM_HTML_MODE_LEGACY));

3. Safeguard Custom Font Loading

If your ERASMD.TTF file is missing, misnamed, or not in the assets folder, it can silently fail and cause text rendering issues. Add a try-catch to handle font loading gracefully:

try {
    font = Typeface.createFromAsset(getAssets(), "ERASMD.TTF");
} catch (Exception e) {
    e.printStackTrace();
    // Fallback to default font if custom one fails to load
    font = Typeface.DEFAULT;
}

4. Clean and Rebuild Your Project

Sometimes Android Studio's cached files cause weird, unexplained crashes. Go to Build > Clean Project, then Build > Rebuild Project to clear old artifacts.

Why This Works #

• Dynamic array length ensures you never loop beyond the bounds of your string arrays, even if you update them later.
• Setting text in one go creates a consistent text structure that Android's rendering system can handle without index errors.
• Safeguarding font loading prevents hidden issues that mess with text measurement and drawing.

Give these steps a try—this should resolve that IndexOutOfBoundsException while keeping your current implementation intact.

内容的提问来源于stack exchange，提问作者user3686177