23rd, Onfocuchangelistener Focus event (learn Android from scratch)

In Android apps, Onfocuchangelistener focus events are essential, and we'll learn how to do it on the basis of the previous chapter.

Basics: Onfocuchangelistener Events

First, the interface

Open the "res/layout/activity_main.xml" file.

1. Drag the 2 edit box EditText from the toolbar to the activity, respectively. The control is from form Widgets.

　　

2. Open the Activity_main.xml file.

[HTML]View Plaincopy

2. <LinearLayout
4. xmlns:android="http://schemas.android.com/apk/res/android"
6. android:layout_width="match_parent"
8. android:layout_height="match_parent"
10. android:orientation="vertical" >
14. <EditText
16. android:id="@+id/mobile"
18. android:layout_width="190DP"
20. android:layout_height="wrap_content"
22. android:text="mobile number" />
26. <EditText
28. android:id="@+id/address"
30. android:layout_width="190DP"
32. android:layout_height="wrap_content"
34. android:text="Address" />
38. </linearlayout>

3, the interface is as follows

　　

Ii. Onitemselectedlistener Events

1. Open the "Src/com.genwoxue.onfocuchange/mainactivity.java" file.

Then enter the following code:

　　

[Java]View Plaincopy

2. Package com.genwoxue.onfocuchange;
6. Import Android.os.Bundle;
8. Import android.app.Activity;
10. Import Android.view.View;
12. Import Android.widget.EditText;
14. Import Android.view.View.OnClickListener;
16. Import Android.view.View.OnFocusChangeListener;
18. Import Android.widget.Toast;
22. Public class Mainactivity extends Activity {
24. //Declaration EditText
26. private EditText etmobile=null;
28. private EditText etaddress=null;
32. @Override
34. protected void OnCreate (Bundle savedinstancestate) {
36. super.oncreate (savedinstancestate);
38. Setcontentview (R.layout.activity_main);
40. //Get EditText
42. Etmobile= (EditText)Super.findviewbyid (r.id.mobile);
44. Etaddress= (EditText)Super.findviewbyid (r.id.address);
46. //Register onclick, Onfocuschange listener
48. Etmobile.setonclicklistener (new Mobileonclicklistener ());
50. Etmobile.setonfocuschangelistener (new Mobileonfocuschanagelistener ());
52. Etaddress.setonclicklistener (new Addressonclicklistener ());
54. Etaddress.setonfocuschangelistener (new Addressonfocuschanagelistener ());
56. }
58. //mobileonclicklistener Click Listener
60. private class Mobileonclicklistener implements onclicklistener{
62. @Override
64. public void OnClick (view view) {
66. Etmobile.settext ("");
68. }
70. }
72. //mobileonfocuschanagelistener Focus Listener
74. private class Mobileonfocuschanagelistener implements onfocuschangelistener{
76. @Override
78. public void Onfocuschange (View view,Boolean hasfocus) {
80. if (View.getid () ==etmobile.getid ())
82. Toast.maketext (Getapplicationcontext (), "Phone text box get focus!"  ", Toast.length_long). Show ();
84. }
86. }
88. //mobileonclicklistener Click Listener
90. private class Addressonclicklistener implements onclicklistener{
92. @Override
94. public void OnClick (view view) {
96. Etaddress.settext ("");
98. }
100. }
102. //mobileonfocuschanagelistener Focus Listener
104. private class Addressonfocuschanagelistener implements onfocuschangelistener{
106. @Override
108. public void Onfocuschange (View view,Boolean hasfocus) {
110. if (View.getid () ==etaddress.getid ())
112. Toast.maketext (Getapplicationcontext (), "Address text box get focus!"  ", Toast.length_long). Show ();
114. }
116. }
118. }

2. The final effect is as follows:

(Get Focus)

　　

(Click to clear the text)