我使用的是第三方库，有一个方法使用DrawableCompat.setTintMode(drawable, PorterDuff.Mode.SRC_IN);。当我在android 5.0+中测试我的应用程序时，没有问题，运行良好。但当谈到android 4.4.4时，它抛出了一个异常：
05-09 13:15:15.030 26447-26447/com.wizchen.athit E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.wizchen.athit, PID: 26447
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.wizchen.athit/com.wizchen.athit.view.activity.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2271)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2320)
at android.app.ActivityThread.access$800(ActivityThread.java:138)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1269)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5117)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at android.support.v4.graphics.drawable.DrawableWrapperDonut.setCompatTintMode(DrawableWrapperDonut.java:278)
at android.support.v4.graphics.drawable.DrawableCompatBase.setTintMode(DrawableCompatBase.java:48)
at android.support.v4.graphics.drawable.DrawableCompat$BaseDrawableImpl.setTintMode(DrawableCompat.java:99)
at android.support.v4.graphics.drawable.DrawableCompat.setTintMode(DrawableCompat.java:400)
at com.wizchen.athit.lib.AppThemeEngine.util.TintHelper.createTintedDrawable(TintHelper.java:359)
at com.wizchen.athit.lib.AppThemeEngine.viewprocessors.ToolbarProcessor.process(ToolbarProcessor.java:117)
at com.wizchen.athit.lib.AppThemeEngine.viewprocessors.ToolbarProcessor.process(ToolbarProcessor.java:44)
at com.wizchen.athit.lib.AppThemeEngine.ATE.postApply(ATE.java:209)
at com.wizchen.athit.lib.AppThemeEngine.ATEActivity.onStart(ATEActivity.java:60)
at com.wizchen.athit.view.activity.MainActivity.onStart(MainActivity.java:68)
at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1183)
at android.app.Activity.performStart(Activity.java:5359)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2244)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2320)
at android.app.ActivityThread.access$800(ActivityThread.java:138)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1269)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5117)
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:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
除了上面的堆栈跟踪，我在控制台中看到了一些错误信息，如下所示：
05-09 13:15:15.030 26447-26447/com.wizchen.athit E/dalvikvm: Could not find class 'android.graphics.drawable.RippleDrawable', referenced from method com.wizchen.athit.lib.AppThemeEngine.util.TintHelper.setTintAuto
这个：
05-09 13:15:15.030 26447-26447/com.wizchen.athit E/dalvikvm: Could not find class 'android.graphics.drawable.RippleDrawable', referenced from method com.wizchen.athit.lib.AppThemeEngine.util.TintHelper.setTintSelector
当然，我在我的项目中编译了v4支持库：）
谁遇到过这个问题？谢谢你的帮助！
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更新1:这就是导致NullPointerException的原因：
@CheckResult
@Nullable
public static Drawable createTintedDrawable(@Nullable Drawable drawable, @ColorInt int color) {
if (drawable == null) return null;
drawable = DrawableCompat.wrap(drawable.mutate());
DrawableCompat.setTintMode(drawable, PorterDuff.Mode.SRC_IN);
DrawableCompat.setTint(drawable, color);
return drawable;
}
阅读以下内容：
如果你查看DrawableCompat的源代码，你会发现任何版本<support library 21该方法不起任何作用。
DrawableCompat的想法似乎并不是在旧版本上崩溃，而是真正提供该功能。
有用提示：
使用support library 22.1，您可以使用DrawableCompat对可绘制内容进行着色。
DrawableCompat.wrap（Drawable）和setTint（）、setTintList（）以及setTintMode（）将正常工作：无需创建和维护单独的仅支持多种颜色的抽绳！
我用过吗？colorPrimary用于在我的项目中创建按钮背景及其原因错误，我会更改吗？colorPrimary到@color/colorPrimary及其对我的工作：）