从Fragment中更新activity中的textview

Question

如何从DialogFragment更新活动A中的TextView

在我的情况下，单击DialogFragment中的关闭按钮后，我需要调用可以改变TextView的方法

this is method from Activity:

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

Onclick按钮在DialogFragment:

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

        new menufeedActivity().setQountText(getCount);

        InfoOrderDialog.this.dismiss();
    };
};

有人知道怎么解决这个问题吗?

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

你可以这样称呼它:

替换:

 new menufeedActivity().setQountText(getCount);

:

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

Answer 2

照我说的做。

TextView textview = (TextView)getActivity().findViewById(R.id.yourtextview);
textview.setText("text");

Answer 3

In kotlin

val textview = activity!!.findViewById<View>(R.id.textView) as TextView
        textview.text = "your_text"

Answer 4

在你的Fragment:调用getActivity()。startActivityForResult -在完成之前的方法，并在承载片段的活动中捕获它:

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
//your method to update textview
setCountText();
}

编辑:我为你找到了一个更好的解决方案。检查一下:https://stackoverflow.com/a/15121529/2245646