setDropDownBackgroundResource在棉花糖的Android不工作

Question

我已经尝试设置为自动填充文本的下拉颜色查看它工作正常，在其他所有的API，但是当过我的联系运行5棉花糖我得到了以下错误

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11-02 17:36:23.815 29058-29058/test.text.com E/AndroidRuntime: FATAL EXCEPTION: main 
11-02 17:36:23.815 29058-29058/test.text.com E/AndroidRuntime: Process: test.text.com, PID: 29058 
11-02 17:36:23.815 29058-29058/test.text.com E/AndroidRuntime: java.lang.NullPointerException: Attempt to invoke virtual method 'android.graphics.drawable.Drawable android.support.v7.internal.widget.TintManager.getDrawable(int)' on a null object reference 
11-02 17:36:23.815 29058-29058/test.text.com E/AndroidRuntime:  at android.support.v7.widget.AppCompatAutoCompleteTextView.setDropDownBackgroundResource(AppCompatAutoCompleteTextView.java:96) 
11-02 17:36:23.815 29058-29058/test.text.com E/AndroidRuntime:  at test.text.com.activity.CreateRideActivity.onWindowFocusChanged(CreateRideActivity.java:369) 
11-02 17:36:23.815 29058-29058/test.text.com E/AndroidRuntime:  at android.support.v7.internal.view.WindowCallbackWrapper.onWindowFocusChanged(WindowCallbackWrapper.java:114) 
11-02 17:36:23.815 29058-29058/test.text.com E/AndroidRuntime:  at android.support.v7.internal.view.WindowCallbackWrapper.onWindowFocusChanged(WindowCallbackWrapper.java:114) 
11-02 17:36:23.815 29058-29058/test.text.com E/AndroidRuntime:  at com.android.internal.policy.PhoneWindow$DecorView.onWindowFocusChanged(PhoneWindow.java:3237) 
11-02 17:36:23.815 29058-29058/test.text.com E/AndroidRuntime:  at android.view.View.dispatchWindowFocusChanged(View.java:9528) 
11-02 17:36:23.815 29058-29058/test.text.com E/AndroidRuntime:  at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:1200) 
11-02 17:36:23.815 29058-29058/test.text.com E/AndroidRuntime:  at android.view.ViewRootImpl$ViewRootHandler.handleMessage(ViewRootImpl.java:3378) 
11-02 17:36:23.815 29058-29058/test.text.com E/AndroidRuntime:  at android.os.Handler.dispatchMessage(Handler.java:102) 
11-02 17:36:23.815 29058-29058/test.text.com E/AndroidRuntime:  at android.os.Looper.loop(Looper.java:148) 
11-02 17:36:23.815 29058-29058/test.text.com E/AndroidRuntime:  at android.app.ActivityThread.main(ActivityThread.java:5417) 
11-02 17:36:23.815 29058-29058/test.text.com E/AndroidRuntime:  at java.lang.reflect.Method.invoke(Native Method) 
11-02 17:36:23.815 29058-29058/test.text.com E/AndroidRuntime:  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
11-02 17:36:23.815 29058-29058/test.text.com E/AndroidRuntime:  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 

我的代码是

AutoSuggestView.setDropDownBackgroundResource(R.drawable.bg_rectangle_white_curve_border_right); 

Answer 1

尝试更新您的程序兼容性库。在当前（23.1.1）版本的appcompat-v7中，AppCompatAutoCompleteTextView中的代码已更改为像这样解析此问题

public void setDropDownBackgroundResource(@DrawableRes int resId) { 
     if (mTintManager != null) { 
      setDropDownBackgroundDrawable(mTintManager.getDrawable(resId)); 
     } else { 
      super.setDropDownBackgroundResource(resId); 
     } 
    }