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java - 如何解决 Textview setText() 在空对象引用上

问题描述

所以我得到这个错误：

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference

我运行了调试工具，这些行是空的：

TextView leftMessageView = (TextView) row.findViewById(R.id.leftmsgr);
leftMessageView.setText(Servermessage);

这是它的来源：

public View getView(int position, View convertView, @NonNull ViewGroup parent) {

    View row;
    LayoutInflater inflater = (LayoutInflater) this.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    ChMessage chMessageObj = getItem(position);
    if (chMessageObj.left) {
        row = inflater.inflate(R.layout.leftmessage, parent, false);
    }else{
        row = inflater.inflate(R.layout.rightmessage, parent, false);
    }

        TextView rightMessageView = (TextView) row.findViewById(R.id.rightmsgr);
        TextView leftMessageView = (TextView) row.findViewById(R.id.leftmsgr);
        rightMessageView.setText(chMessageObj.message);
        leftMessageView.setText(Servermessage);

    return row;
}

不知道为什么它不为空？

任何帮助都会很棒！

谢谢

标签： javanullpointerexception

解决方案

尝试NullPointerException使用以下代码修复：

public View getView(int position, View convertView, @NonNull ViewGroup parent) 
{   
    View row;
    LayoutInflater inflater = (LayoutInflater) this.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    ChMessage chMessageObj = getItem(position);
    if (chMessageObj.left) {
        row = inflater.inflate(R.layout.leftmessage, parent, false);
    }else{
        row = inflater.inflate(R.layout.rightmessage, parent, false);
    }

        TextView rightMessageView = (TextView) row.findViewById(R.id.rightmsgr);
        TextView leftMessageView = (TextView) row.findViewById(R.id.leftmsgr);
        if (rightMessageView!=null) {
          rightMessageView.setText(chMessageObj.message);
        }
        if (leftMessageView!=null) {
          leftMessageView.setText(Servermessage);
        }

    return row;
}

然后，我不认为 TextView 为空是正确的。检查您的 XML 布局。希望能帮助到你。

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