如何在使用自定义对话框类时修改文本并单击侦听器?

Question

>我有一个带有自定义布局的对话框类。现在我想更改文本值和来自不同活动的按钮单击侦听器。我正在尝试这样做，但出现错误。这是我的源代码。任何帮助或建议将不胜感激。

public class MyDialog extends Dialog {
TextView dialogTitle, dialogMessage;
Button dialogCancel, dialogOk;
public MyDialog(@NonNull Context context) {
super(context);
}
@Override
public void dismiss() {
super.dismiss();
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.dialog_layout);
//..................REFERENCE
dialogTitle = (TextView) findViewById(R.id.txt_ttl);
dialogMessage = (TextView) findViewById(R.id.txt_msg);
dialogCancel = (Button) findViewById(R.id.btn_cancel_id);
dialogOk = (Button) findViewById(R.id.btn_ok_id);
//dialogTitle.setText("title has been changed");
}
private void dialogCancel(){
}
private void dialogOk(){
}
public void changeDialogTitle(String dTitle){
dialogTitle.setText(dTitle);
}
}

从我正在使用的其他活动中

...onCreate{...
MyDialog myDialog = new MyDialog(this);
}
// on button click show dialog
public void showDialog(View view) {
myDialog.changeDialogTitle("Title");
myDialog.show();
}

Answer 1

这是真的，也许你可以传递标题，作为参数

首先在 MyDialog 类中添加参数

public class MyDialog extends Dialog {
TextView dialogTitle, dialogMessage;
Button dialogCancel, dialogOk;
String title;
public MyDialog(@NonNull Context context, String title) {
super(context);
this.title = title;
}
@Override
public void dismiss() {
super.dismiss();
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.dialog_layout);
//..................REFERENCE
dialogTitle = (TextView) findViewById(R.id.txt_ttl);
dialogMessage = (TextView) findViewById(R.id.txt_msg);
dialogCancel = (Button) findViewById(R.id.btn_cancel_id);
dialogOk = (Button) findViewById(R.id.btn_ok_id);
// set your title in here
dialogTitle.setText(title);
}
private void dialogCancel(){
}
private void dialogOk(){
}
public void changeDialogTitle(String dTitle){
dialogTitle.setText(dTitle);
}
}

之后在您的活动中调用这样的函数

MyDialog myDialog = new Mydialog(this,"My New Title");
myDialog.show

Answer 2

请参阅下面的代码片段：

public class MyDialog extends Dialog {
TextView dialogTitle, dialogMessage;
Button dialogCancel, dialogOk;
String title;
public MyDialog(@NonNull Context context, final String title) {
super(context);
this.title=title;
}
@Override
public void dismiss() {
super.dismiss();
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.dialog_layout);
//..................REFERENCE
dialogTitle = (TextView) findViewById(R.id.txt_ttl);
dialogMessage = (TextView) findViewById(R.id.txt_msg);
dialogCancel = (Button) findViewById(R.id.btn_cancel_id);
dialogOk = (Button) findViewById(R.id.btn_ok_id);
dialogTitle.setText(title);
}
private void dialogCancel(){
}
private void dialogOk(){
}
public void changeDialogTitle(String dTitle){
dialogTitle.setText(dTitle);
}
}

----------

// on button click show dialog
public void showDialog(View view) {
MyDialog myDialog = new MyDialog(this, "Title");
myDialog.show();
}

MyDialog myDialog = new MyDialog(this， "Title"(;可以将标题和消息发送到构造函数中，它将在 Dialog onCreate 方法时在 UI 上设置。

Answer 3

您得到空指针异常，因为您在显示对话框之前更改了对话框标题。因此，首先显示对话框，然后更改标题。将其更改为：

myDialog.show();
myDialog.changeDialogTitle("Title");

Answer 4

看起来您正在尝试创建一个独立于生命周期的实用程序类，您只需要将onCreate 方法的代码移动到 MyDialog 构造函数，如下所示。

public class MyDialog extends Dialog {
TextView dialogTitle, dialogMessage;
Button dialogCancel, dialogOk;
public MyDialog(@NonNull Context context) {
super(context);
setContentView(R.layout.dialog_layout);
//..................REFERENCE
dialogTitle = (TextView) findViewById(R.id.txt_ttl);
dialogMessage = (TextView) findViewById(R.id.txt_msg);
dialogCancel = (Button) findViewById(R.id.btn_cancel_id);
dialogOk = (Button) findViewById(R.id.btn_ok_id);
//dialogTitle.setText("title has been changed");
}
@Override
public void dismiss() {
super.dismiss();
}
private void dialogCancel(){
}
private void dialogOk(){
}
public void changeDialogTitle(String dTitle){
dialogTitle.setText(dTitle);
}
}

现在，您可以随时更改视图的内容。它应该有效。