前言

近期把项目中的support包升级到了26.1.0，看起来在手机上运行的稳稳的，没翻船！之后提交，测试就报了一个bug说5.0以下的手机都不能运行了！因此就排查了问题原因。

问题

首先我们复现一下问题，看看崩溃日志，崩溃日志主要有以下两个：

E/VdcInflateDelegate: Exception while inflating <vector>
org.xmlpull.v1.XmlPullParserException: Binary XML file line #17<vector> tag requires viewportWidth > 0
  at android.support.graphics.drawable.VectorDrawableCompat.updateStateFromTypedArray(VectorDrawableCompat.java:690)
  at android.support.graphics.drawable.VectorDrawableCompat.inflate(VectorDrawableCompat.java:623)
  at android.support.graphics.drawable.VectorDrawableCompat.createFromXmlInner(VectorDrawableCompat.java:586)
  at android.support.v7.widget.AppCompatDrawableManager$VdcInflateDelegate.createFromXmlInner(AppCompatDrawableManager.java:777)
  at android.support.v7.widget.AppCompatDrawableManager.loadDrawableFromDelegates(AppCompatDrawableManager.java:365)
  at android.support.v7.widget.AppCompatDrawableManager.getDrawable(AppCompatDrawableManager.java:195)
  at android.support.v7.widget.AppCompatDrawableManager.getDrawable(AppCompatDrawableManager.java:188)
  at android.support.v7.widget.AppCompatDrawableManager.checkVectorDrawableSetup(AppCompatDrawableManager.java:755)
  at android.support.v7.widget.AppCompatDrawableManager.getDrawable(AppCompatDrawableManager.java:193)
  at android.support.v7.widget.TintTypedArray.getDrawableIfKnown(TintTypedArray.java:87)
  at android.support.v7.app.AppCompatDelegateImplBase.<init>(AppCompatDelegateImplBase.java:128)
  at android.support.v7.app.AppCompatDelegateImplV9.<init>(AppCompatDelegateImplV9.java:149)
  at android.support.v7.app.AppCompatDelegateImplV11.<init>(AppCompatDelegateImplV11.java:29)
  at android.support.v7.app.AppCompatDelegateImplV14.<init>(AppCompatDelegateImplV14.java:54)
  at android.support.v7.app.AppCompatDelegate.create(AppCompatDelegate.java:202)
  at android.support.v7.app.AppCompatDelegate.create(AppCompatDelegate.java:183)
  at android.support.v7.app.AppCompatActivity.getDelegate(AppCompatActivity.java:519)
  at com.xxx.common.activity.BaseActionBarActivity.installInflaterFactory(BaseActionBarActivity.java:192)
  at com.xxx.common.activity.BaseActionBarActivity.onCreate(BaseActionBarActivity.java:156)
  at com.xxx.activity.login.EntranceActivity.onCreate(EntranceActivity.java:64)
  at android.app.Activity.performCreate(Activity.java:5356)
  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1089)
  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2151)
  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2236)
  at android.app.ActivityThread.access$800(ActivityThread.java:138)
  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1199)
  at android.os.Handler.dispatchMessage(Handler.java:102)
  at android.os.Looper.loop(Looper.java:136)
  at android.app.ActivityThread.main(ActivityThread.java:5122)
  at java.lang.reflect.Method.invokeNative(Native Method)
  at java.lang.reflect.Method.invoke(Method.java:515)
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:602)
  at dalvik.system.NativeStart.main(Native Method)

以及如下的错误，如下的错误会导致系统崩溃不能运行。

E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.xxx.debug, PID: 3565
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.xxx.debug/com.xxx.activity.login.EntranceActivity}: android.content.res.Resources$NotFoundException: File res/drawable/abc_vector_test.xml from drawable resource ID #0x7f020052
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2187)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2236)
at android.app.ActivityThread.access$800(ActivityThread.java:138)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1199)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5122)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:602)
at dalvik.system.NativeStart.main(Native Method)
Caused by: android.content.res.Resources$NotFoundException: File res/drawable/abc_vector_test.xml from drawable resource ID #0x7f020052
at android.content.res.Resources.loadDrawable(Resources.java:2124)
at android.content.res.Resources.getDrawable(Resources.java:704)
at android.support.v7.widget.VectorEnabledTintResources.superGetDrawable(VectorEnabledTintResources.java:74)
at android.support.v7.widget.AppCompatDrawableManager.onDrawableLoadedFromResources(AppCompatDrawableManager.java:435)
at android.support.v7.widget.VectorEnabledTintResources.getDrawable(VectorEnabledTintResources.java:67)
at android.support.v4.content.ContextCompat.getDrawable(ContextCompat.java:353)
at android.support.v7.widget.AppCompatDrawableManager.getDrawable(AppCompatDrawableManager.java:200)
at android.support.v7.widget.AppCompatDrawableManager.getDrawable(AppCompatDrawableManager.java:188)
at android.support.v7.widget.AppCompatDrawableManager.checkVectorDrawableSetup(AppCompatDrawableManager.java:755)
at android.support.v7.widget.AppCompatDrawableManager.getDrawable(AppCompatDrawableManager.java:193)
at android.support.v7.widget.TintTypedArray.getDrawableIfKnown(TintTypedArray.java:87)
at android.support.v7.app.AppCompatDelegateImplBase.<init>(AppCompatDelegateImplBase.java:128)
at android.support.v7.app.AppCompatDelegateImplV9.<init>(AppCompatDelegateImplV9.java:149)
at android.support.v7.app.AppCompatDelegateImplV11.<init>(AppCompatDelegateImplV11.java:29)
at android.support.v7.app.AppCompatDelegateImplV14.<init>(AppCompatDelegateImplV14.java:54)
at android.support.v7.app.AppCompatDelegate.create(AppCompatDelegate.java:202)
at android.support.v7.app.AppCompatDelegate.create(AppCompatDelegate.java:183)
at android.support.v7.app.AppCompatActivity.getDelegate(AppCompatActivity.java:519)
at com.xxx.common.activity.BaseActionBarActivity.installInflaterFactory(BaseActionBarActivity.java:192)
at com.xxx.common.activity.BaseActionBarActivity.onCreate(BaseActionBarActivity.java:156)
at com.xxx.activity.login.EntranceActivity.onCreate(EntranceActivity.java:64)
at android.app.Activity.performCreate(Activity.java:5356)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1089)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2151)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2236) 
at android.app.ActivityThread.access$800(ActivityThread.java:138) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1199) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:136) 
at android.app.ActivityThread.main(ActivityThread.java:5122) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:515) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:602) 
at dalvik.system.NativeStart.main(Native Method) 
Caused by: org.xmlpull.v1.XmlPullParserException: Binary XML file line #17: invalid drawable tag vector
at android.graphics.drawable.Drawable.createFromXmlInner(Drawable.java:933)
at android.graphics.drawable.Drawable.createFromXml(Drawable.java:877)
at android.content.res.Resources.loadDrawable(Resources.java:2120)
at android.content.res.Resources.getDrawable(Resources.java:704) 
at android.support.v7.widget.VectorEnabledTintResources.superGetDrawable(VectorEnabledTintResources.java:74) 
at android.support.v7.widget.AppCompatDrawableManager.onDrawableLoadedFromResources(AppCompatDrawableManager.java:435) 
at android.support.v7.widget.VectorEnabledTintResources.getDrawable(VectorEnabledTintResources.java:67) 
at android.support.v4.content.ContextCompat.getDrawable(ContextCompat.java:353) 
at android.support.v7.widget.AppCompatDrawableManager.getDrawable(AppCompatDrawableManager.java:200) 
at android.support.v7.widget.AppCompatDrawableManager.getDrawable(AppCompatDrawableManager.java:188) 
at android.support.v7.widget.AppCompatDrawableManager.checkVectorDrawableSetup(AppCompatDrawableManager.java:755) 
at android.support.v7.widget.AppCompatDrawableManager.getDrawable(AppCompatDrawableManager.java:193) 
at android.support.v7.widget.TintTypedArray.getDrawableIfKnown(TintTypedArray.java:87) 
at android.support.v7.app.AppCompatDelegateImplBase.<init>(AppCompatDelegateImplBase.java:128) 
at android.support.v7.app.AppCompatDelegateImplV9.<init>(AppCompatDelegateImplV9.java:149) 
at android.support.v7.app.AppCompatDelegateImplV11.<init>(AppCompatDelegateImplV11.java:29) 
at android.support.v7.app.AppCompatDelegateImplV14.<init>(AppCompatDelegateImplV14.java:54) 
at android.support.v7.app.AppCompatDelegate.create(AppCompatDelegate.java:202) 
at android.support.v7.app.AppCompatDelegate.create(AppCompatDelegate.java:183) 
at android.support.v7.app.AppCompatActivity.getDelegate(AppCompatActivity.java:519) 
at com.xxx.common.activity.BaseActionBarActivity.installInflaterFactory(BaseActionBarActivity.java:192) 
at com.xxx.common.activity.BaseActionBarActivity.onCreate(BaseActionBarActivity.java:156) 
at com.xxx.activity.login.EntranceActivity.onCreate(EntranceActivity.java:64) 
at android.app.Activity.performCreate(Activity.java:5356) 
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1089) 
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2151) 
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2236) 
at android.app.ActivityThread.access$800(ActivityThread.java:138) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1199) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:136) 
at android.app.ActivityThread.main(ActivityThread.java:5122) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:515) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:602) 
at dalvik.system.NativeStart.main(Native Method)

原因

由于历史原因，以前做了很多分包的操作，因此gradle版本一直是1.2.3，不是当前最新的版本，因此写了一个Demo发现采用最新的版本不会出现崩溃。因此根据代码我们可以看到有如下执行路径：

日志1

Activity继承自AppCompatActivity，在Activity加载的时候会调用到getDelegate()函数：

@NonNull
public AppCompatDelegate getDelegate() {
    if (mDelegate == null) {
        mDelegate = AppCompatDelegate.create(this, this);
    }
    return mDelegate;
}

最终会调用到create函数：

private static AppCompatDelegate create(Context context, Window window,
        AppCompatCallback callback) {
    if (Build.VERSION.SDK_INT >= 24) {
        return new AppCompatDelegateImplN(context, window, callback);
    } else if (Build.VERSION.SDK_INT >= 23) {
        return new AppCompatDelegateImplV23(context, window, callback);
    } else if (Build.VERSION.SDK_INT >= 14) {
        return new AppCompatDelegateImplV14(context, window, callback);
    } else if (Build.VERSION.SDK_INT >= 11) {
        return new AppCompatDelegateImplV11(context, window, callback);
    } else {
        return new AppCompatDelegateImplV9(context, window, callback);
    }
}

这里我们主要是5.0以下版本会崩溃，因此我们需要查看AppCompatDelegateImplV14，里面我们一直跟踪调用父类，最终会调用到如下的代码：

final TintTypedArray a = TintTypedArray.obtainStyledAttributes(
context, null, sWindowBackgroundStyleable);
final Drawable winBg = a.getDrawableIfKnown(0);

这里先解析是否有windowbackground属性，并且获取对应的drawable：

public Drawable getDrawableIfKnown(int index) {
    if (mWrapped.hasValue(index)) {
        final int resourceId = mWrapped.getResourceId(index, 0);
        if (resourceId != 0) {
            return AppCompatDrawableManager.get().getDrawable(mContext, resourceId, true);
        }
    }
    return null;
}

这里recouseId不等于0，进入到AppCompatDrawableManager.中的getDrawable函数：

Drawable getDrawable(@NonNull Context context, @DrawableRes int resId,
        boolean failIfNotKnown) {
    checkVectorDrawableSetup(context);

    Drawable drawable = loadDrawableFromDelegates(context, resId);
    if (drawable == null) {
        drawable = createDrawableIfNeeded(context, resId);
    }
    if (drawable == null) {
        drawable = ContextCompat.getDrawable(context, resId);
    }

    if (drawable != null) {
        // Tint it if needed
        drawable = tintDrawable(context, resId, failIfNotKnown, drawable);
    }
    if (drawable != null) {
        // See if we need to 'fix' the drawable
        DrawableUtils.fixDrawable(drawable);
    }
    return drawable;
}

getDrawable函数中首先调用了checkVectorDrawableSetup(context)函数：

private void checkVectorDrawableSetup(@NonNull Context context) {
    if (mHasCheckedVectorDrawableSetup) {
        // We've already checked so return now...
        return;
    }
    // Here we will check that a known Vector drawable resource inside AppCompat can be
    // correctly decoded
    mHasCheckedVectorDrawableSetup = true;
    final Drawable d = getDrawable(context, R.drawable.abc_vector_test);
    if (d == null || !isVectorDrawable(d)) {
        mHasCheckedVectorDrawableSetup = false;
        throw new IllegalStateException("This app has been built with an incorrect "
                + "configuration. Please configure your build for VectorDrawableCompat.");
    }
}

我们发现上面有一个资源R.drawable.abc_vector_test，这个系统support包里的Vector资源，我们先来看看他的xml：


<?xml version="1.0" encoding="utf-8"?>
<vector xmlns:android="http://schemas.android.com/apk/res/android"
        android:width="24dp"
        android:height="24dp"
        android:viewportHeight="24.0"
        android:viewportWidth="24.0">
    <path
        android:fillColor="@android:color/white"
        android:pathData="M20,11L7.8,11l5.6,-5.6L12,4l-8,8l8,8l1.4,-1.4L7.8,13L20,13L20,11z"/>
</vector>

我们继续往下看，这里初始状态为false，因此会继续往下执行，首先改为了true，并且继续调用了上面的getDrawable函数，因为这里改为了true，因此会进入的到getDrawable函数中的loadDrawableFromDelegates：


private Drawable loadDrawableFromDelegates(@NonNull Context context, @DrawableRes int resId) {
    if (mDelegates != null && !mDelegates.isEmpty()) {
         ............................
        if (tv.string != null && tv.string.toString().endsWith(".xml")) {
            // If the resource is an XML file, let's try and parse it
            try {
                final XmlPullParser parser = res.getXml(resId);
                final AttributeSet attrs = Xml.asAttributeSet(parser);
                int type;
                while ((type = parser.next()) != XmlPullParser.START_TAG &&
                        type != XmlPullParser.END_DOCUMENT) {
                    // Empty loop
                }
                if (type != XmlPullParser.START_TAG) {
                    throw new XmlPullParserException("No start tag found");
                }

                final String tagName = parser.getName();
                // Add the tag name to the cache
                mKnownDrawableIdTags.append(resId, tagName);

                // Now try and find a delegate for the tag name and inflate if found
                final InflateDelegate delegate = mDelegates.get(tagName);
                if (delegate != null) {
                    dr = delegate.createFromXmlInner(context, parser, attrs,
                            context.getTheme());
                }
                if (dr != null) {
                    // Add it to the drawable cache
                    dr.setChangingConfigurations(tv.changingConfigurations);
                    if (addDrawableToCache(context, key, dr) && DEBUG) {
                        Log.i(TAG, "[loadDrawableFromDelegates] Saved drawable to cache: " +
                                context.getResources().getResourceName(resId));
                    }
                }
            } catch (Exception e) {
                Log.e(TAG, "Exception while inflating drawable", e);
            }
        }
    .............
        return dr;
    }

    return null;
}

这里我们先删除了部分代码，只看最重要的部分，那就是delegate.createFromXmlInner，实际调用的是VectorDrawableCompat
.createFromXmlInner(context.getResources(), parser, attrs, theme)，继续调用createFromXmlInner中的inflate函数，inflate中继续调用到updateStateFromTypedArray：

private void updateStateFromTypedArray(TypedArray a, XmlPullParser parser)
        throws XmlPullParserException {
    final VectorDrawableCompatState state = mVectorState;
    final VPathRenderer pathRenderer = state.mVPathRenderer;

    // Account for any configuration changes.
    // state.mChangingConfigurations |= Utils.getChangingConfigurations(a);

    final int mode = TypedArrayUtils.getNamedInt(a, parser, "tintMode",
            AndroidResources.STYLEABLE_VECTOR_DRAWABLE_TINT_MODE, -1);
    state.mTintMode = parseTintModeCompat(mode, Mode.SRC_IN);

    final ColorStateList tint =
            a.getColorStateList(AndroidResources.STYLEABLE_VECTOR_DRAWABLE_TINT);
    if (tint != null) {
        state.mTint = tint;
    }

    state.mAutoMirrored = TypedArrayUtils.getNamedBoolean(a, parser, "autoMirrored",
            AndroidResources.STYLEABLE_VECTOR_DRAWABLE_AUTO_MIRRORED, state.mAutoMirrored);

    pathRenderer.mViewportWidth = TypedArrayUtils.getNamedFloat(a, parser, "viewportWidth",
            AndroidResources.STYLEABLE_VECTOR_DRAWABLE_VIEWPORT_WIDTH,
            pathRenderer.mViewportWidth);

    pathRenderer.mViewportHeight = TypedArrayUtils.getNamedFloat(a, parser, "viewportHeight",
            AndroidResources.STYLEABLE_VECTOR_DRAWABLE_VIEWPORT_HEIGHT,
            pathRenderer.mViewportHeight);

    if (pathRenderer.mViewportWidth <= 0) {
        throw new XmlPullParserException(a.getPositionDescription() +
                "<vector> tag requires viewportWidth > 0");
    } else if (pathRenderer.mViewportHeight <= 0) {
        throw new XmlPullParserException(a.getPositionDescription() +
                "<vector> tag requires viewportHeight > 0");
    }

    pathRenderer.mBaseWidth = a.getDimension(
            AndroidResources.STYLEABLE_VECTOR_DRAWABLE_WIDTH, pathRenderer.mBaseWidth);
    pathRenderer.mBaseHeight = a.getDimension(
            AndroidResources.STYLEABLE_VECTOR_DRAWABLE_HEIGHT, pathRenderer.mBaseHeight);
    if (pathRenderer.mBaseWidth <= 0) {
        throw new XmlPullParserException(a.getPositionDescription() +
                "<vector> tag requires width > 0");
    } else if (pathRenderer.mBaseHeight <= 0) {
        throw new XmlPullParserException(a.getPositionDescription() +
                "<vector> tag requires height > 0");
    }

    // shown up from API 11.
    final float alphaInFloat = TypedArrayUtils.getNamedFloat(a, parser, "alpha",
            AndroidResources.STYLEABLE_VECTOR_DRAWABLE_ALPHA, pathRenderer.getAlpha());
    pathRenderer.setAlpha(alphaInFloat);

    final String name = a.getString(AndroidResources.STYLEABLE_VECTOR_DRAWABLE_NAME);
    if (name != null) {
        pathRenderer.mRootName = name;
        pathRenderer.mVGTargetsMap.put(name, pathRenderer);
    }
}

这里调用TypedArrayUtils.getNamedFloat会去解析viewportWidth与viewportHeight：

public static float getNamedFloat(@NonNull TypedArray a, @NonNull XmlPullParser parser,
        @NonNull String attrName, @StyleableRes int resId, float defaultValue) {
    final boolean hasAttr = hasAttribute(parser, attrName);
    if (!hasAttr) {
        return defaultValue;
    } else {
        return a.getFloat(resId, defaultValue);
    }
}

   public static boolean hasAttribute(@NonNull XmlPullParser parser, @NonNull String attrName) {
    return parser.getAttributeValue(NAMESPACE, attrName) != null;
}

这里会发现viewportHeight与viewportWidth不存在，但是我们上面的xml里明明有这两个属性，为什么到这个地方就没有了？

gradle 1.2.3调用aapt编译资源，因为VectorDrawable是21才加入的，因此他不认识这两个属性，被优化掉了，同时优化掉的还有path中的内容

由于上面的原因，xml在编译后viewportWidth与viewportHeight会移除了，因此在解析的时候返回了0，系统检测该值，抛出了异常！

为什么23的版本不崩溃

23版本的内容未做检查，不会调用checkVectorDrawableSetup函数

日志2

上面有两个日志，第一个日志我们已经清楚了，只是抛出了异常，而不会导致崩溃，那为什么系统会崩溃，我们看到上面日志的下半部分与日志1相同，所以原因也是一样的，我们继续往下看loadDrawableFromDelegates解析失败后drawable为空，会继续执行createDrawableIfNeeded，这里只是对想要资源做了检查，因此最终会调用到ContextCompat.getDrawable中：

public static final Drawable getDrawable(Context context, @DrawableRes int id) {
    if (Build.VERSION.SDK_INT >= 21) {
        return context.getDrawable(id);
    } else if (Build.VERSION.SDK_INT >= 16) {
        return context.getResources().getDrawable(id);
    } else {
        // Prior to JELLY_BEAN, Resources.getDrawable() would not correctly
        // retrieve the final configuration density when the resource ID
        // is a reference another Drawable resource. As a workaround, try
        // to resolve the drawable reference manually.
        final int resolvedId;
        synchronized (sLock) {
            if (sTempValue == null) {
                sTempValue = new TypedValue();
            }
            context.getResources().getValue(id, sTempValue, true);
            resolvedId = sTempValue.resourceId;
        }
        return context.getResources().getDrawable(resolvedId);
    }
}

这里我们调用到context.getResources().getDrawable(id)，而5.0以上的版本会调用 context.getDrawable(id)，这里的Resources是什么？我们在AppCompatActivity中有一个如下函数：

@Override
public Resources getResources() {
    if (mResources == null && VectorEnabledTintResources.shouldBeUsed()) {
        mResources = new VectorEnabledTintResources(this, super.getResources());
    }
    return mResources == null ? super.getResources() : mResources;
}

如果这里VectorEnabledTintResources.shouldBeUsed是true因此会进入到VectorEnabledTintResources，如果为false调用系统，5.0以下的系统是不能解析Vector的因此这里我们需要让上面的条件为true，shouldBeUsed的代码如下：

public static boolean shouldBeUsed() {
    return AppCompatDelegate.isCompatVectorFromResourcesEnabled()
            && Build.VERSION.SDK_INT <= MAX_SDK_WHERE_REQUIRED;
}

这里条件2已经满足了，因此我们需要满足条件1，那条件1怎么满足，AppCompatDelegate有一个静态函数，我们可以再系统初始化的时候进行调用：

AppCompatDelegate.setCompatVectorFromResourcesEnabled(true)

如果这里条件不满足，系统rescoures不认识该资源，系统崩溃，如果这里条件满足，那就会调用VectorEnabledTintResources的getDrawable函数:

@Override
public Drawable getDrawable(int id) throws NotFoundException {
    final Context context = mContextRef.get();
    if (context != null) {
        return AppCompatDrawableManager.get().onDrawableLoadedFromResources(context, this, id);
    } else {
        return super.getDrawable(id);

这里context不为空，如果为空调用下面崩溃。这里继续调用AppCompatDrawableManager的onDrawableLoadedFromResources函数：

Drawable onDrawableLoadedFromResources(@NonNull Context context,
        @NonNull VectorEnabledTintResources resources, @DrawableRes final int resId) {
    Drawable drawable = loadDrawableFromDelegates(context, resId);
    if (drawable == null) {
        drawable = resources.superGetDrawable(resId);
    }
    if (drawable != null) {
        return tintDrawable(context, resId, false, drawable);
    }
    return null;
}

这里我们看到了一个熟悉的函数，loadDrawableFromDelegates，这里下面就跟日志1一样，因为viewportWidth与viewportHeight不存在，导致出现日志2下班部分的异常，这里返回drawable为空，继续调用resources.superGetDrawable，进入系统resources调用，由于5.0以下版本解析不了vector TAG，具体调用代码如下:

public static Drawable createFromXmlInner(Resources r, XmlPullParser parser, AttributeSet attrs)
throws XmlPullParserException, IOException {
   Drawable drawable;

   final String name = parser.getName();

   if (name.equals("selector")) {
       drawable = new StateListDrawable();
   } else if (name.equals("level-list")) {
       drawable = new LevelListDrawable();
   } else if (name.equals("layer-list")) {
       drawable = new LayerDrawable();
   } else if (name.equals("transition")) {
       drawable = new TransitionDrawable();
   } else if (name.equals("color")) {
       drawable = new ColorDrawable();
   } else if (name.equals("shape")) {
       drawable = new GradientDrawable();
   } else if (name.equals("scale")) {
       drawable = new ScaleDrawable();
   } else if (name.equals("clip")) {
       drawable = new ClipDrawable();
   } else if (name.equals("rotate")) {
       drawable = new RotateDrawable();
   } else if (name.equals("animated-rotate")) {
       drawable = new AnimatedRotateDrawable();
   } else if (name.equals("animation-list")) {
       drawable = new AnimationDrawable();
   } else if (name.equals("inset")) {
       drawable = new InsetDrawable();
   } else if (name.equals("bitmap")) {
       //noinspection deprecation
       drawable = new BitmapDrawable(r);
       if (r != null) {
          ((BitmapDrawable) drawable).setTargetDensity(r.getDisplayMetrics());
       }
   } else if (name.equals("nine-patch")) {
       drawable = new NinePatchDrawable();
       if (r != null) {
           ((NinePatchDrawable) drawable).setTargetDensity(r.getDisplayMetrics());
        }
   } else {
       throw new XmlPullParserException(parser.getPositionDescription() +
               ": invalid drawable tag " + name);
   }

   drawable.inflate(r, parser, attrs);
   return drawable;
}

未解析vector标签，抛出异常，大于fileNotFound，该异常未被捕获，因此系统崩溃。

5.0以上版本，虽然viewportWidth与viewportHeight被擦除，但是可以解析vector标签，因此会生成对应的vectordrawable。

解决方案

上面的出现的种种问题怎么解决？主要有以下几种方案：

方案1

最正确的解法还是需要升级gradle，将gradle升级最新版本就可以了，只要能大于1.2.3就有解，首先在调用如下代码：

 AppCompatDelegate.setCompatVectorFromResourcesEnabled(true);

如果是1.5版本如下：

// Gradle Plugin 1.5  
 android {  
   defaultConfig {  
     generatedDensities = []  
  }  

  // This is handled for you by the 2.0+ Gradle Plugin  
  aaptOptions {  
    additionalParameters "--no-version-vectors"  
  }  
 }

2.0版本如下：

// Gradle Plugin 2.0+  
 android {  
   defaultConfig {  
     vectorDrawables.useSupportLibrary = true  
    }  
 }

更新的版本啥都不用做。

方案2

如果因为种种原因不能升级gradle怎么办？也可以，我们可以用高版本打包，将Vector编译的资源拷贝出来，在低版本打包的时候进行覆盖。

该方案工作量太大，每次打包都必须覆盖，并且需要找到所有的vector资源

方案3

该方案是一个取巧的方案那就是不升级support包，只要在24以下，都未做检查，因此不会崩溃。

该方案的前提是自生应用中不能包含Vector资源，如有该方案行不通
如果必须升级support包，该方案也行不通

方案4

我们知道资源是在aapt中被移除的，怎么才能不移除，添加方案1中的参数，然而gradle1.2.3不识别该参数，怎么办？我们可以采用级联调用，我们在build-tool中新建aapt，重命名掉系统的aapt，由我们的aapt调用系统的aapt在调用时，添加对应的参数：

#!/bin/sh
#ashap=$*
#echo "input $*"
#echo "xxx-test $*" >> /Users/asha/Library/Android/sdk/build-tools/25.0.2/cmd.txt
/Users/xxxxx/Library/Android/sdk/build-tools/25.0.2/aapt-x $* "--no-version-vectors"
exit $?
#exit 0

这样就将对应的参数传递给了对应的aapt。

该方案必须要新建appt，让系统先调用到自己的，再调用到系统

总结

这次是因为系统的recyclerview有bug，必须升级所以才引发了这一系列的问题。总之升级gradle是王道。

Binary XML file line #17 tag requires viewportWidth >0

前言

问题

原因

日志1

日志2

解决方案

方案1

方案2

方案3

方案4

总结

Binary XML file line #17 tag requires viewportWidth >0

Android應用程序管理服務啓動過程淺析（PackageManagerService）

一步一步學習JNI（一）

Android 標題欄（一）

Android拖拽動畫實現

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