java - 如果 EditText 为空，则阻止用户关闭警报对话框

Question

我正在使用 AlertDialog Box 和 EditText，用户可以在其中输入他的名字。我想防止当 EditText 为空时警报对话框关闭。

下面是我的代码

 private void request_user_name() {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("Enter name:");

        final EditText input_field = new EditText(this);
        input_field.setText(sharedpreferences.getString("username",""));
        final SharedPreferences.Editor editor = sharedpreferences.edit();

        builder.setCancelable(false);
        builder.setView(input_field);
        String savedName = sharedpreferences.getString(username,"");
        input_field.setText(savedName);
        input_field.setSelection(input_field.getText().length());
        builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                name = input_field.getText().toString();
               

                editor.putString(username, name);
                editor.apply();
            }
        });

        builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                dialogInterface.cancel();
                request_user_name();
            }
        });

        builder.show();
    }

我尝试插入

 if(TextUtils.isEmpty(name)) {
                input_field.setError("Your message");
                return;
            }

在AlertDialog Box里面是这样的，但是没用

 private void request_user_name() {
    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setTitle("Enter name:");

    final EditText input_field = new EditText(this);
    input_field.setText(sharedpreferences.getString("username",""));
    final SharedPreferences.Editor editor = sharedpreferences.edit();

    builder.setCancelable(false);
    builder.setView(input_field);
    String savedName = sharedpreferences.getString(username,"");
    input_field.setText(savedName);
    input_field.setSelection(input_field.getText().length());
    builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialogInterface, int i) {
            name = input_field.getText().toString();
            if(TextUtils.isEmpty(name)) {
                input_field.setError("Your message");
                return;
            }


            editor.putString(username, name);
            editor.apply();
        }
    });

    builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialogInterface, int i) {
            dialogInterface.cancel();
            request_user_name();
        }
    });

    builder.show();
}

下面是图像文件，我有

以及我想要得到的图像

提前致谢。

Answer 1

使用setCancelable(false) .

设置一下即可

    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setTitle("Enter name:");
    builder.setCancelable(false);