Attempt to read from field 'int android.view.ViewGroup$LayoutParams.width' on a null object referen

最新推荐文章于 2024-11-07 21:28:21 发布

原创最新推荐文章于 2024-11-07 21:28:21 发布 · 9.3k 阅读

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本文深入探讨了在使用RecyclerView时遇到的空布局参数异常问题，详细解析了NullPointerException的产生原因，即尝试从null对象引用读取字段。通过对比LayoutInflater.inflate方法的不同调用方式，提供了解决方案，强调了正确传递父视图的重要性。

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: kodulf.swiperefreshlayoutrecyclerviewdemo, PID: 8661
    java.lang.NullPointerException: Attempt to read from field 'int android.view.ViewGroup$LayoutParams.width' on a null object reference
        at android.view.ViewGroup$LayoutParams.<init>(ViewGroup.java:7547)
        at android.view.ViewGroup$MarginLayoutParams.<init>(ViewGroup.java:7861)
        at kodulf.swiperefreshlayoutrecyclerviewdemo.MainActivity$MyAdapter.onCreateViewHolder(MainActivity.java:181)
        at kodulf.swiperefreshlayoutrecyclerviewdemo.MainActivity$MyAdapter.onCreateViewHolder(MainActivity.java:161)
        at android.support.v7.widget.RecyclerView$Adapter.createViewHolder(RecyclerView.java:6794)
        at android.support.v7.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:5975)
        at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5858)

因为inflate的时候：

View v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.item, null, false);


解决办法：
View v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.item, viewGroup, false);