Android Basics: HelloWorld Toast Usage

One: Look at the program

Second: Change the layout:

1: Under res resources, find layout, open Activity_main.xml

Below the graphical layout view, you can customize the drag interface elements to adjust the layout. For example, add a button

2: Open activity_main.xml View, edit source code, add Trigger function for button

3: Adding functions to activity

public void Test (view view) {System.out.println ("------test----"); Toast toast = Toast.maketext (Mainactivity.this, "clicked Button", Toast.length_short); The screen is centered, and the x-axis and y-axis offsets are 0  toast.setgravity (gravity.center, 0, 0); Toast.show ();}

Three: Start the simulator

When you click the button, an informational prompt appears.

Four: Usage of toast

A Toast is a view that quickly displays a small amount of information to the user. A Toast floats on the application to display information to the user, it never gets the focus, does not affect the user's input, and so on, mainly for some help/hints.

The most common way to create a Toast is to use a static method Toast.maketext

1. Default display mode

Java code

1. //First parameter: the current context. Available Getapplicationcontext () or this
2. ///second parameter: the string to display. It's also a string ID in r.string.
3. ///Third parameter: The length of time displayed. Toast defaults to two length_long (long) and Length_short (short), or milliseconds, such as 2000ms
4. Toast Toast=toast.maketext (Getapplicationcontext (), "Default Toast", Toast.length_short);
5. //Show toast Information
6. Toast.show ();

2. Customizing the display location

Java code

2. Toast Toast=toast.maketext (Getapplicationcontext (), "toast with custom display location", Toast.length_short);
4. //First parameter: Sets the location where the toast appears on the screen. My current settings are centered on the top
6. ///second parameter: The offset of the horizontal x-axis of the toast position relative to the first parameter, positive offset to the right, negative to left offset
8. ///third parameter: Same as the second argument
10. //If you set an offset that exceeds the range of the screen, the toast will appear in the screen near the outside border
12. Toast.setgravity (gravity.top| Gravity.center,--- -);
14. //center display, x-axis and y-axis offset are 0
16. //toast.setgravity (gravity.center, 0, 0);
18. Toast.show ();

3. With the picture

Java code

2. Toast Toast=toast.maketext (Getapplicationcontext (), "show toast with pictures", + );
4. Toast.setgravity (Gravity.center, 0, 0);
6. //Create picture View Object
8. ImageView imageview= New ImageView (Getapplicationcontext ());
10. //Set Picture
12. Imageview.setimageresource (R.drawable.ic_launcher);
14. //Get the toast layout
16. LinearLayout Toastview = (linearlayout) Toast.getview ();
18. //Set this layout to landscape
20. Toastview.setorientation (linearlayout.horizontal);
22. //ImageView is added to the first position in this layout
24. Toastview.addview (ImageView, 0);
26. Toast.show ();

4. Fully customizable display mode

Java code

2. //inflater means inflatable .
4. //layoutinflater This class is used to instantiate the layout of an XML file to its corresponding view object
6. Layoutinflater inflater = Getlayoutinflater ();
8. //Populate a View object by developing an XML file and layout ID
10. View layout = Inflater.inflate (R.layout.custom2, (ViewGroup) Findviewbyid (r.id.lltoast));
14. ImageView image = (ImageView) Layout.findviewbyid (r.id.tvimagetoast);
16. //Set picture in Picture view in Layout
18. Image.setimageresource (R.drawable.ic_launcher);
22. TextView title = (TextView) Layout.findviewbyid (r.id.tvtitletoast);
24. //Set title
26. Title.settext ("title bar");
30. TextView Text = (TextView) Layout.findviewbyid (r.id.tvtexttoast);
32. //Set content
34. Text.settext ("fully customizable toast");
38. Toast toast= New Toast (Getapplicationcontext ());
40. Toast.setgravity (Gravity.center, 0, 0);
42. Toast.setduration (Toast.length_long);
44. Toast.setview (layout);
46. Toast.show ();

5. Calls from other threads through Handler

Java code

2. //Call Method 1
4. //thread th=new Thread (this);
6. //th.start ();
8. //Call Method 2
10. Handler.post (new Runnable () {
12. @Override
14. Public void Run () {
16. Showtoast ();
18. }
20. });

Java code

1. Public void Showtoast () {
2. Toast Toast=toast.maketext (Getapplicationcontext (), "toast calls in other threads to display", toast.length_short);
3. Toast.show ();
4. }

Java code

2. Handler handler=New Handler () {
4. @Override
6. Public void handlemessage (Message msg) {
8. int what=msg.what;
10. Switch (what) {
12. Case 1:
14. Showtoast ();
16. break;
18. default:
20. break;
22. }
26. Super. Handlemessage (msg);
28. }
30. };

Java code

1. @Override
2. Public void Run () {
3. Handler.sendemptymessage (1);
4. }

Android Basics: HelloWorld Toast Usage