Custom Dialog EditText returns null

2019-08-26 20:17发布

问题:

Many people have faced similar issues, and I think I have followed and fixed all the issues as mentioned in all those posts on stackoverflow.

  • setContentView to my layout
  • initializing the edittext with dialog.findViewById

But I am still stuck at the nullpointer. What am I missing ?

Layout name is serverchange.xml. Contents of serverchange.xml are

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

<EditText
    android:id="@+id/server"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:inputType="textUri" />

<TextView
    android:id="@+id/status"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:editable="true" />

</LinearLayout>

Dialog is created on by selecting a menu on optionsmenu.

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle item selection
    switch (item.getItemId()) {
    case R.id.serverChange:
        showDialog(SERVER_CHANGE);
        // newGame();
        return true;
    }
}

I get a NullPointerException at

if (changeServerView == null) throw new NullPointerException() ;

Code:

@Override
protected Dialog onCreateDialog(int id) {
    switch (id) {
    case SERVER_CHANGE:
        serverChangeDialog = new Dialog(this);
        serverChangeDialog.setContentView(R.layout.serverchange);
        serverChangeDialog.setTitle("Change Server");
        serverChangeDialog.setOnKeyListener(this);
        serverChangeDialog.show();
        changeServerView = (EditText) serverChangeDialog.findViewById(R.id.serverChange);
        status = (TextView) serverChangeDialog.findViewById(R.id.status);
        if (changeServerView == null) throw new NullPointerException() ;
    }
    return null;
}

My onKey implementation

@Override
public boolean onKey(DialogInterface dialog, int keyCode, KeyEvent event) {
    if (dialog == serverChangeDialog) {
        if (keyCode == KeyEvent.KEYCODE_ENTER) {
            String backupServer = server;
            server = changeServerView.getText().toString();

Here too I get a NullPointerException.

回答1:

Wrong id refrences from xml file,

Use server instead of serverChange

changeServerView = (EditText) serverChangeDialog.findViewById(R.id.server);
                                                                   ^^^^^^