2023學年完整公開課版長按事件

《通信業(yè)務開發(fā)》課程長按事件長按LongClick事件PART18-7事件特性監(jiān)聽接口實例演示事件特性示例控件長按超過2s觸發(fā)的事件，常用于設置桌面類似應用接口：View.OnLongClickListener.

onLongClick()實現步驟：獲取監(jiān)聽對象：創(chuàng)建監(jiān)聽器類,實現View.OnLongClickListener注冊監(jiān)聽器：

setOnLongClickListener()規(guī)則監(jiān)聽接口publicstaticinterfaceView.OnLongClickListener{ publicbooleanonLongClick(Viewv);}voidsetOnLongClickListener(View.OnLongClickListener

l)實例演示<LinearLayout

xmlns:android="/apk/res/android"

android:layout_width="match_parent"

android:layout_height="match_parent"

>

<ImageView

android:id="@+id/img"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignParentTop="true"

android:layout_centerHorizontal="true"

android:layout_marginTop="18dp"

android:src="@drawable/a"

tools:ignore="ContentDescription"

/>

</LinearLayout>

XML布局實例演示public

class

MainActivity

extends

Activity

{

@Overridepublic

voidonCreate(BundlesavedInstanceState){super.onCreate(savedInstanceState); setContentView(R.layout.main);

ImageViewimg=(ImageView)findViewById(R.id.img); img.setOnLongClickListener(newOnLongClickListener(){

@Override

public

boolean

onLongClick(Viewview){

try{clearWallpaper();setWallpaper(img.getResources().openRawResource(R.drawable.mldn_bg)); }catch(Exceptione){ }

return

true;} });}}

選項改變監(jiān)聽實現No.方法類型描述1publicvoidclearWallpaper()普通清除已有的手機屏幕2publicvoidsetWallpaper(Bitmapbitmap)普通通過Bitmap設置手機屏幕3publicvoidsetWallpaper(InputStreamdata)普通通過輸入流設置手機屏幕4publicDrawablegetWallpaper()普通