Android handler use of the third

We know that handler can send runnable messages, and he can also send messages with a message. The code is as follows

XML code

1 <Relativelayoutxmlns:android= "Http://schemas.android.com/apk/res/android"2 Xmlns:tools= "Http://schemas.android.com/tools"3 Android:layout_width= "Match_parent"4 Android:layout_height= "Match_parent"5 Android:paddingbottom= "@dimen/activity_vertical_margin"6 Android:paddingleft= "@dimen/activity_horizontal_margin"7 Android:paddingright= "@dimen/activity_horizontal_margin"8 Android:paddingtop= "@dimen/activity_vertical_margin"9 Tools:context= "Com.example.android_handler." Mainactivity " >Ten  One     <TextView A         Android:id= "@+id/textview" - Android:layout_width= "Wrap_content" - Android:layout_height= "Wrap_content" the Android:text= "@string/hello_world" /> -  - </Relativelayout>

Java code

1  PackageCom.example.android_handler;2 3 Importandroid.app.Activity;4 ImportAndroid.os.Bundle;5 ImportAndroid.os.Handler;6 ImportAndroid.os.Message;7 ImportAndroid.widget.TextView;8 9  Public classMainactivityextendsActivity {Ten     PrivateTextView TextView =NULL; One     PrivateHandler Handler =NewHandler () { A          Public voidhandlemessage (android.os.Message msg) { -Textview.settext ("" +msg.obj); -         }; the     }; - @Override -     protected voidonCreate (Bundle savedinstancestate) { -         Super. OnCreate (savedinstancestate); + Setcontentview (r.layout.activity_main); -TextView =(TextView) Findviewbyid (R.id.textview); +         NewThread () { A              Public voidrun () { at                 //This method can reclaim a message that already exists in the system -Message message =Message.obtain (); -                 /* - * This too - * Message message = Handler.obtainmessage -                  */ in                  -                  to                 //obj can be used to pass multiple objects +Message.obj = "123"; - handler.sendmessage (message); the             }; * }.start (); $     }Panax Notoginseng}

At the same time, we know that using handler can implement the rotation of the picture in a imageview, but if we want the picture to end, the main use is handler, because handler not only can send a message, but also can remove a message. The code is as follows

XML code

1<linearlayout xmlns:android= "Http://schemas.android.com/apk/res/android"2Xmlns:tools= "Http://schemas.android.com/tools"3Android:layout_width= "Match_parent"4android:layout_height= "Match_parent"5android:orientation= "Vertical"6Tools:context= "Com.example.android_handler1. Mainactivity ">7<ImageView8Android:id= "@+id/imageview"9Android:layout_width= "Wrap_content"Tenandroid:layout_height= "Wrap_content" One/> A<Button -Android:id= "@+id/button" -Android:layout_width= "Match_parent" theandroid:layout_height= "Wrap_content" -android:text= "@string/button_string" -/> -  +</LinearLayout>

Java code

1  PackageCom.example.android_handler1;2 3 Importandroid.app.Activity;4 ImportAndroid.os.Bundle;5 ImportAndroid.os.Handler;6 ImportAndroid.util.Log;7 ImportAndroid.view.View;8 ImportAndroid.view.View.OnClickListener;9 ImportAndroid.widget.Button;Ten ImportAndroid.widget.ImageView; One  A  Public classMainactivityextendsActivityImplementsOnclicklistener { -     PrivateHandler Handler =NewHandler (); -     PrivateImageView ImageView =NULL; the     PrivateMyrunnable runnable =Newmyrunnable (); -     PrivateButton Button =NULL; -     //Create an array of pictures -     Private intimages[]={r.drawable.image1, r.drawable.image2,r.drawable.image3}; +     //Create an index to record the subscript of the current picture -     Private intindex = 0; + @Override A     protected voidonCreate (Bundle savedinstancestate) { at         Super. OnCreate (savedinstancestate); - Setcontentview (r.layout.activity_main); -ImageView =(ImageView) Findviewbyid (R.id.imageview); -button =(Button) Findviewbyid (R.id.button); -Button.setonclicklistener ( This); -         NewThread () { in              Public voidrun () { -                 //The first parameter is an object that passes in a runnable to                 //The second parameter means the time each picture is displayed +Handler.postdelayed (runnable, 1000); -             }; the }.start (); *          $         Panax Notoginseng     } -     //Create a myrunnable class to manipulate the picture on the Imagevie the     classMyrunnableImplementsRunnable +     { A  the          Public voidrun () { +index++; -index = index% 3; $ Imageview.setimageresource (Images[index]); $Handler.postdelayed (runnable, 1000); -         } -          the     } -      Public voidOnClick (View v) {Wuyi         //use handler to remove runnable, to enable the carousel of Stop Pictures the handler.removecallbacks (runnable); -          Wu     } -}

Android handler use of the third