java - android中的layoutinflater nullpointerexception

Question

我想Activity入驻FrameLayout。这是我的代码：

FrameLayout fl = new FrameLayout(this);
fl = (FrameLayout ) findViewById(R.id.actioncontent);           
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);           
View myview =LayoutInflater.from(this).inflate(R.layout.wallpaper, null);
fl.removeAllViews();
fl.addView(myview);

我收到一个错误NullPointerException。

Answer 1

你需要使用inflator而不是LayoutInflater.from(this)

LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

            View myview =LayoutInflater.from(this).inflate(R.layout.wallpaper, null);
            fl.removeAllViews();
                fl.addView(myview);

用下面的代码替换上面的代码

LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

            View myview =inflater .inflate(R.layout.wallpaper, null);
            fl.removeAllViews();
                fl.addView(myview);

Answer 2

您没有说明“this”是什么，或者 NPE 发生在哪里 - 但可能是“this”呈现了错误的上下文。尝试改用您的活动名称？例如，MainActivity.this

此外，正如我在下面所述，将 from 替换View myview =LayoutInflater.from(this).inflate为View myview = inflater.inflate

Answer 3

改变

LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

至

LayoutInflater inflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);