Question

我在这里发现了一些类似的问题，但他们所有人都对我这样的新手感到困惑，或者没有帮助解决我的问题：我有一个TextView电视。通过单击它我想显示一个带EditText + Cancel-和Update-Buttons的自定义AlertDialog。通过单击我的对话框的更新按钮，我想用Dialog中的EditText值替换相同TextView（tv）的文本。这是我的一个注意事项：

...
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    final TextView tv̶̶C̶̶l̶̶i̶̶c̶̶k̶̶e̶̶d̶ = (TextView) findViewById(R.id.tv_id);
    tv.setText("Initial value");

    tv.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            UpdateDialogFragment updDiag = new UpdateDialogFragment();
            updDiag.show(getFragmentManager(), "dialog");
            tv.setText(updDiag.value); // I try to get the value of EditText like this, but it doesn't work
        }
        });
}

public class UpdateDialogFragment extends DialogFragment {
    String value; // I try to get the value of EditText like this, but it doesn't work
    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {

        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        LayoutInflater inflater = getActivity().getLayoutInflater();

        builder.setView(inflater.inflate(R.layout.edit_tv, null))
                .setPositiveButton("Update", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int id) {
                        EditText et = (EditText) UpdateDialogFragment.this.getDialog().findViewById(R.id.et_tv);
                        value = et.getText().toString();  // I try to get the value of EditText like this, but it doesn't work
                    }
                })
                .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int id) {
                        UpdateDialogFragment.this.getDialog().cancel();
                    }
                });
        return builder.create();
    }
}

我的edit_tv.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <EditText
        android:id="@+id/et_tv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:ems="10"
        android:layout_marginTop="40dp"
        android:hint="Enter text ..."
        android:layout_gravity="center_horizontal">

        <requestFocus />
    </EditText>

</LinearLayout>

activity_main.xml中：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.yev.tabletasting.MainActivity">

    <TextView
        android:id="@+id/tv_id"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />    

</RelativeLayout>

在我的情况下，电视文本将被设置为＆＃34;＆＃34; （可能为null）点击＆＃34;更新＆＃34;。我会感谢你的每一条建议，感谢你的期待！

Answer 1

这是你在TextView onClickListener中应该拥有的：

AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Write new value for TextView");
final EditText editText = new EditText(this);
builder.setView(editText);
builder.setPositiveButton("Update", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int id) {                 
                    }
                });
AlertDialog dialog = builder.create();
dialog.show();
dialog.getButton(DialogInterface.BUTTON_POSITIVE).setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        String newValue = editText.getText().toString();
                        if(newValue.lenght() == 0)
                            Toast.makeText(this, "You need to type something in the editText", Toast.LENGTH_LONG).show();
                        }else{
                            tv.setText(newValue);
                            dialog.dismiss();
                        }
                    });

可能需要进行一些小的更改，因为我在这里编写了代码。希望能帮助到你。祝你好运：）

LE：对于editText对话框，您不需要额外的Fragment和xml文件。

Answer 2

好的，所以你还没有真正提到过为什么你喜欢使用DialogFragment而不仅仅是AlertDialog，正如Victor Holotescu所回答的那样。但是接下来，当我尝试点击更新按钮时，我尝试了你的代码并设法收到 NullPointerException 。所以我查看了它并修改了代码，这里是：

MainActivity

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(final Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final TextView tv = (TextView) findViewById(R.id.tv_id);
        tv.setText("Initial value");

        tv.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                UpdateDialogFragment updDiag = new UpdateDialogFragment().newInstance(tv); // Passed the TextView here
                updDiag.show(getFragmentManager(), "dialog");
            }
        });
    }

    public static class UpdateDialogFragment extends DialogFragment {
        String value; // I try to get the value of EditText like this, but it doesn't work
        TextView tvToEdit;

        public UpdateDialogFragment newInstance(TextView tvToEdit){
            UpdateDialogFragment udf = new UpdateDialogFragment();
            udf.tvToEdit = tvToEdit;
            return udf;
        }

        @Override
        public Dialog onCreateDialog(Bundle savedInstanceState) {
            AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
            LayoutInflater inflater = getActivity().getLayoutInflater();

            builder.setView(inflater.inflate(R.layout.edit_tv, null))
                    .setPositiveButton("Update", new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int id) {
                            EditText et = (EditText) UpdateDialogFragment.this.getDialog().findViewById(R.id.et_tv);
                            value = et.getText().toString();
                            tvToEdit.setText(value);
                        }
                    })
                    .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int id) {
                            UpdateDialogFragment.this.getDialog().cancel();
                        }
                    });
            return builder.create();
        }
    }
}

我在代码中添加了一些TODO条评论（在下面标有阅读评论。：）），检查出来。我测试了它，它运行正常。希望这能够以某种方式帮助你。有关AlertDialog和DialogFragment的更多信息，这里有一个很好的帖子 - SendCancelNotification。

修改

好。所以我编辑了它，你只需要通过创建一个newInstance方法将TextView传递给UpdateDialogFragment，在这里引用它DialogFragment advantages over AlertDialog - 希望这会有所帮助。：）

自定义AlertDialog的EditText值到Textview

2 个答案: