Android应用开发中的条件弹出消息

Question

首先，我对Android Studio和Android应用程序开发非常陌生。我想在我的应用程序中显示一个有条件的弹出窗口，只有当条件不满足时弹出窗口才会出现。

    Double billAmount = new Double(etBillAmount.getText().toString());
    Double TipPercentage = new Double(etTipPercentage.getText().toString());

    // The popup should be given when the Tip percentage is greater than 100 or else continue with 
       the code
    if (TipPercentage > 100)
    {
        System.out.println("Please enter Tip Percentage between 0 to 100. Thank you");
        System.exit(0);
    }
    Double totalBill;
    Double totalTip;

    totalTip = TipPercentage*billAmount/100;
    totalBill = totalTip + billAmount;

    tvTotal.setText("$ " + totalTip.toString());   
    tvTip.setText("$ " + totalBill.toString());

这是代码，当if语句中的条件不满足时，我想弹出一条消息。请帮助我解决它只在线性布局格式，如果可能的话。

请帮助我提前感谢大家:)！

Answer 1

对于弹出消息，您可以使用Toast

Toast.makeText(this, "Please enter Tip Percentage between 0 to 100. Thank you", Toast.LENGTH_SHORT).show();

因此，您需要在if代码块中添加toast，而不是system.out.println

if (TipPercentage > 100){
Toast.makeText(this, "Please enter Tip Percentage between 0 to 100. Thank you", Toast.LENGTH_SHORT).show();
}

或者，您也可以使用警报对话框Too.For警报对话框点击此链接https://developer.android.com/guide/topics/ui/dialogs

Answer 2

the code
if (TipPercentage > 100){
System.out.println("Please enter Tip Percentage between 0 to 100. Thank you");
System.exit(0);}else{
dialogOpenTop(NotificationDialogActivity.this,"pass string");
}}
public void dialogOpenTop(final Context context, String toke) {
final Dialog dialog = new Dialog(NotificationDialogActivity.this);           dialog.setContentView(R.layout.alert);
dialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
            dialog.setCancelable(false);
            dialog.setTitle("Demo for bottom dialog");
            LinearLayout someLayout = dialog.findViewById(R.id.someLayout);
            Button btnOk = dialog.findViewById(R.id.btnOk);
}
layout
<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/scrollViewLuogo"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:descendantFocusability="beforeDescendants"
    android:focusableInTouchMode="true"
    android:fitsSystemWindows="false"
    >
    <LinearLayout
        android:focusableInTouchMode="true"
        android:padding="@dimen/margin_10dp"
        android:id="@+id/someLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:background="@drawable/dialog_background"
        android:orientation="vertical">
        <TextView
            android:padding="@dimen/margin_10dp"
            android:textStyle="bold"
            android:id="@+id/title_message"
            android:layout_gravity="center"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Your message"

            android:layout_marginBottom="4dp"
            android:textSize="18sp" />

        <ScrollView android:id="@+id/scroll_view"
            android:layout_width="match_parent"
            android:fitsSystemWindows="true"
            android:fadeScrollbars="false"
            style="@style/scroll_style"
            android:layout_height="match_parent"
            tools:ignore="UselessParent">

            <LinearLayout android:id="@+id/scroll_layout"
                android:padding="@dimen/margin_10dp"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="vertical" >




                <ImageView
                    android:layout_below="@+id/title_message"
                    android:adjustViewBounds="true"
                    android:id="@+id/btnAlert"
                    android:layout_gravity="center"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:visibility="visible" />


                <TextView

                    android:paddingTop="@dimen/margin_10dp"
                    android:paddingBottom="@dimen/margin_10dp"
                    android:layout_below="@+id/btnAlert"
                    android:layout_gravity="center"
                    android:id="@+id/text"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="YOur message"
                    android:textSize="18sp" />

                <Button
                    android:id="@+id/btnOk"
                    android:minWidth="@dimen/margin_0dp"
                    android:minHeight="@dimen/margin_0dp"
                    android:textSize="@dimen/text_20sp"
                    android:paddingTop="2dp"
                    android:paddingBottom="2dp"
                    android:paddingLeft="@dimen/margin_height_50dp"
                    android:paddingRight="@dimen/margin_height_50dp"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
           android:layout_gravity="center"
                    android:layout_marginTop="2dp"
                    android:background="@drawable/dialog_button"
                    android:focusable="true"
                    android:focusedByDefault="true"
                    android:text="Ok" />

                <Button
                    android:visibility="gone"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="Next actvity"
                    android:id="@+id/nxt"/>
            </LinearLayout>
        </ScrollView>
    </LinearLayout>
</LinearLayout>