Android應用程序崩潰導致創建打開意圖

Question

嘗試打開“ ReadActivity”時，我的Android應用程序“電子郵件”崩潰。

在MainActivity中聲明的OpenMail（）方法應啟動ReadActivity：

public void OpenMail(View v, int index) {
    String[] mail = {"x", "y", "z"};

    Intent readIntent = new Intent(this, ReadActivity.class); <-- Error occurs here

    readIntent.putExtra("mail", mail);

    startActivity(readIntent);
}

該方法在ListViewAdapter中調用：

@Override
public View getView(final int position, View convertView, ViewGroup parent) {
    Holder holder = new Holder();

    View rowView = inflater.inflate(R.layout.listview_item, null);

    holder.imageView = (ImageView) rowView.findViewById(R.id.imageView);
    holder.txvSenderMail = (TextView) rowView.findViewById(R.id.txvSender);
    holder.txvSubject = (TextView) rowView.findViewById(R.id.txvSubject);

    holder.imageView.setImageResource(ImageID[position]);
    holder.txvSenderMail.setText(SenderMail[position]);
    holder.txvSubject.setText(Subject[position]);

    rowView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            new MainActivity().OpenMail(v, position);
        }
    });

    return rowView;
}

錯誤：java.lang.NullPointerException：嘗試在空對象引用上調用虛擬方法“ android.app.ActivityThread $ ApplicationThread android.app.ActivityThread.getApplicationThread（）”

我希望有人能幫助我！ 謝謝！

Answer 1

您實際上是在嘗試創建新的MainActivity時

new MainActivity().OpenMail(v, context, position);

如果您目前在MainActivity課上，我想您想做這樣的事情：

getActivity().OpenMail(v, context, position);

當然，不要忘記將ReadActivity添加到AndroidManifest