Java – Android Studio validates errors running on API < 17

I’m porting an app from Eclipse to Android Studio and I’m getting a validation error when trying to run the app on an emulator with an API less than 17. I would appreciate any guidance on how to handle this. Here’s what appears in logcat on the API 8 emulator:

12-27 01:48:27.189 431-431/com.zigzagworld.icjl.tanachbible W/dalvikvm: VFY: register1 v10 type 12, wanted 10
12-27 01:48:27.189 431-431/com.zigzagworld.icjl.tanachbible W/dalvikvm: VFY:  rejecting opcode 0x70 at 0x005e
12-27 01:48:27.189 431-431/com.zigzagworld.icjl.tanachbible W/dalvikvm: VFY:  rejected Lcom/zigzagworld/fonts/GlyphMetrics;.<init> (SSS[S)V
12-27 01:48:27.189 431-431/com.zigzagworld.icjl.tanachbible W/dalvikvm: Verifier rejected class Lcom/zigzagworld/fonts/GlyphMetrics;

Then (not surprisingly) the application crashes and java.lang.VerifyError appears. The same .apk file will run fine at API level 17 and above. API 17 and later have different code paths, but the GlyphMetrics class is used at some point regardless of the API level. (If a different code path affects whether a class produces validation errors when loaded, please let me know!)

The GlyphMetrics class is a very simple container for some metric information about the homemade bitmap fonts we use in our application:

package com.zigzagworld.fonts;

import static com.zigzagworld.fonts.Diacritics.LOWER_DIACRITIC;
import static com.zigzagworld.fonts.Diacritics.UPPER_DIACRITIC;

/**
 * Represents the layout metrics for a glyph.
 * 
 * @author Ted Hopp
 */
public final class GlyphMetrics {

public static final short[] EMPTY_EXCLUSION = new short[0];
    public static final short[][] EMPTY_EXCLUSIONS = { EMPTY_EXCLUSION, EMPTY_EXCLUSION };
    /** The width of the glyph image, in pixels. */
    public short width;
    /** The height of the glyph image, in pixels. */
    public short height;
    /**
     * The distance in pixels between the top of the glyph image and the
     * baseline of the line. A positive value means that the top of the glyph
     * should be above the baseline of the line; a negative value means that the
     * top of the glyph should be below the baseline of the line.
     */
    public short baseline;
    /**
     * The upper and lower axes for placement of diacriticals. Each axis is the
     * distance from the left of the glyph image at which diacriticals should be
     * centered. (The formatting algorithm for the font may move diacriticals
     * from this position to avoid interference between glyphs.)
     */
    public short[] axes;
    /**
     * The upper and lower exclusion zone arrays. If there are <i>n</i> upper
     * (say) zones, the upper array has length length 2*<i>n</i>. The array has
     * the left edge of the first zone, the right edge of the first zone, the
     * left edge of the second zone, etc. The lower zone data are organized in
     * the same way.
     */
    public short[][] zones;

public GlyphMetrics(short width, short height, short baseline, short[] layoutData) {
        this.width = width;
        this.height = height;
        this.baseline = baseline;
        axes = new short[2];
        width >>= 1;  for the rest of this, we need the half-width
        if (layoutData == null || layoutData.length == 0) {
            axes[UPPER_DIACRITIC] = axes[LOWER_DIACRITIC] = width;
            zones = EMPTY_EXCLUSIONS;
        } else {
            axes[UPPER_DIACRITIC] = layoutData[0];
            if (layoutData.length < 2) {
                axes[LOWER_DIACRITIC] = width;
            } else {
                axes[LOWER_DIACRITIC] = layoutData[1];
            }
            if (layoutData.length < 5) {
                zones = EMPTY_EXCLUSIONS;
            } else {
                int nUpper = layoutData[2] << 1;
                zones = new short[2][];
                zones[UPPER_DIACRITIC] = new short[nUpper];
                System.arraycopy(layoutData, 3, zones[UPPER_DIACRITIC], 0, nUpper);

int lowerStart = 3 + nUpper;
                if (layoutData.length < 2 + lowerStart) {
                    zones[LOWER_DIACRITIC] = EMPTY_EXCLUSION;
                } else {
                    int nLower = layoutData[lowerStart++] << 1;
                    zones[LOWER_DIACRITIC] = new short[nLower];
                    System.arraycopy(layoutData, lowerStart, zones[LOWER_DIACRITIC], 0, nLower);
                }
            }
        }
    }
}

(The imported UPPER_DIACRITIC and LOWER_DIACRITIC are constants 0 and 1, respectively.) )

I’m building it using Android Studio 2.0 Preview 4 with the Gradle plugin com.android.tools.build:gradle:2.0.0-alpha3 and JDK 1.7.0_80. This is the build.gradle file for the .apk module:

apply plugin: 'com.android.application'

android {
    compileSdkVersion 23
    buildToolsVersion '23.0.2'
    defaultConfig {
        applicationId "com.zigzagworld.icjl.tanachbible"
        minSdkVersion 8
        targetSdkVersion 23
        versionCode 10800310
        versionName "3.1.0"
        manifestPlaceholders = [
                appName: "App",
                v8TOCActivityName: "BaseTOCActivity",
                v8PurchaseActivityName: "PurchaseActivity",
                v17TOCActivityName: "TOCActivity",
                v17PurchaseActivityName: "PurchaseActivity",
        ]
    }
    signingConfigs {
         redacted for this post
    }
    buildTypes {
        release {
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
            noinspection GroovyAssignabilityCheck
            signingConfig // redacted
        }
    }
    flavorDimensions "market"
    productFlavors {
        google {
            dimension "market"
            manifestPlaceholders = [
                appName: "App_Google",
                v8TOCActivityName: "TOCActivity_Google",
                v8PurchaseActivityName: "GooglePurchaseActivity",
                v17TOCActivityName: "TOCActivity_Google",
                v17PurchaseActivityName: "GooglePurchaseActivity"
            ]
        }
        amazon {
            dimension "market"
            manifestPlaceholders = [
                appName: "App_Amazon",
                v8TOCActivityName: "BaseTOCActivity",
                v8PurchaseActivityName: "PurchaseActivity",
                v17TOCActivityName: "TOCActivity",
                v17PurchaseActivityName: "PurchaseActivity"
            ]
        }
        sideLoad {
            dimension "market"
            manifestPlaceholders = [
                    appName: "App_Unlicensed",
                    v8TOCActivityName: "BaseTOCActivity",
                    v8PurchaseActivityName: "PurchaseActivity",
                    v17TOCActivityName: "TOCActivity",
                    v17PurchaseActivityName: "PurchaseActivity"
            ]
        }
    }
}

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.1.1'
    compile 'com.android.support:support-annotations:23.1.1'
    compile project(':Tanach Data')
    googleCompile project(':Google Vending')
    amazonCompile project(':Amazon Vending')
}

The problem occurs in the debug build type, so ProGuard is not in the frame at this time.

After spending a few days on this, I just found that downgrading the gradle plugin from 2.0.0-alpha3 to 1.5.0 would make the problem go away.

That’s the price we pay to stay ahead of the curve.