android - 从 Fragment 更新 Activity 中的 textview

Question

如何从 DialogFragment 更新 Activity A 中的 TextView？

在我的例子中，点击DialogFragment中的关闭按钮后，我需要调用可以改变TextView的方法

这是来自 Activity 的方法:

public void setCountText(String text){
    CountItem = (TextView) findViewById(R.id.tv_numOfItem);
    CountItem.setText(text);
}

DialogFragment 中的点击按钮:

View.OnClickListener closeHandler = new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub


        new menufeedActivity().setQountText(getCount);


        InfoOrderDialog.this.dismiss();

    };

};

有人知道怎么解决吗？

04-29 03:08:17.513: E/AndroidRuntime(1738): FATAL EXCEPTION: main
04-29 03:08:17.513: E/AndroidRuntime(1738): java.lang.NullPointerException
04-29 03:08:17.513: E/AndroidRuntime(1738):     at android.app.Activity.findViewById(Activity.java:1744)
04-29 03:08:17.513: E/AndroidRuntime(1738):     at com.example.android.rssfeed.menufeedActivity.setQountText(menufeedActivity.java:169)
04-29 03:08:17.513: E/AndroidRuntime(1738):     at com.example.android.rssfeed.InfoOrderDialog$2.onClick(InfoOrderDialog.java:110)
04-29 03:08:17.513: E/AndroidRuntime(1738):     at android.view.View.performClick(View.java:3110)
04-29 03:08:17.513: E/AndroidRuntime(1738):     at android.view.View$PerformClick.run(View.java:11928)
04-29 03:08:17.513: E/AndroidRuntime(1738):     at android.os.Handler.handleCallback(Handler.java:587)
04-29 03:08:17.513: E/AndroidRuntime(1738):     at android.os.Handler.dispatchMessage(Handler.java:92)
04-29 03:08:17.513: E/AndroidRuntime(1738):     at android.os.Looper.loop(Looper.java:132)
04-29 03:08:17.513: E/AndroidRuntime(1738):     at android.app.ActivityThread.main(ActivityThread.java:4025)
04-29 03:08:17.513: E/AndroidRuntime(1738):     at java.lang.reflect.Method.invokeNative(Native Method)
04-29 03:08:17.513: E/AndroidRuntime(1738):     at java.lang.reflect.Method.invoke(Method.java:491)
04-29 03:08:17.513: E/AndroidRuntime(1738):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841)
04-29 03:08:17.513: E/AndroidRuntime(1738):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
04-29 03:08:17.513: E/AndroidRuntime(1738):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

你可以这样调用它:

替换:

 new menufeedActivity().setQountText(getCount);

与:

((menufeedActivity) getActivity()).setCountText(getCount);