如何在Android的自定义对话框中设置TextView的值答案

【问题标题】：How to set the value of TextView in Custom Dialog in Android如何在Android的自定义对话框中设置TextView的值
【发布时间】：2015-10-18 01:14:00
【问题描述】：

单击 Activity 中的片段之一后，我想在自定义对话框中设置 TextView 的值。对话框在被调用后使用自定义文本视图运行良好。问题是当我尝试调用 changeMessageText("Hello") 函数时，它总是显示 NullPointerException。

ProgressDialogFragment.java

public class ProgressDialogFragment extends DialogFragment {

        private TextView txtMessage;
        private AlertDialog.Builder mBuilder;

        public static ProgressDialogFragment newInstance(AlertDialog.Builder builder){
            ProgressDialogFragment progressDialogFragment = new ProgressDialogFragment();
            progressDialogFragment.mBuilder = builder;
            return progressDialogFragment;
        }

        @Nullable
        @Override
        public Dialog onCreateDialog(Bundle savedInstanceState) {

            View view = getLayoutInflater(savedInstanceState).inflate(R.layout.dialog_progress, null);
            txtMessage = (TextView) view.findViewById(R.id.txtMessage);

            changeMessageText("Hello World by default"); // this one works

            mBuilder.setView(view);

            return mBuilder.create();

        }
        public void changeMessageText(String text){
            txtMessage.setText(text);
        }
}

示例代码点击按钮后

AlertDialog.Builder builder = new AlertDialog.Builder(this);
ProgressDialogFragment progressDialogFragment = ProgressDialogFragment.newInstance(builder);
progressDialogFragment.show(getSupportFragmentManager(),"progress_dialog");
// dialog box shows until the following function is called.

progressDialogFragment.changeMessageText("Hello");

【问题讨论】：

标签： java android

【解决方案1】：

当progressDialogFragment.changeMessageText("Hello");被调用时，txtMessage还没有被创建。

1) 将private String message; 添加到ProgressDialogFragment。

2) 更改changeMessageText

public void changeMessageText(String text){
    message = text;
    if(txtMessage != null){
        txtMessage.setText(text);
   }            
}

3) 在mBuilder.setView(view);之后添加

if(message!=null && !message.isEmpty()){
    txtMessage.setText(message);
}

4) 删除onCreateDialog中的changeMessageText("Hello World by default");

而且。它不适合我。

View view = getLayoutInflater(savedInstanceState).inflate(R.layout.dialog_progress, null);

我改了。

LayoutInflater inflater = getActivity().getLayoutInflater();
View view = inflater.inflate(R.layout.dialog_progress, null);

希望对你有所帮助。

【讨论】：