Android---Gettag () and Settag () magical

In Android, Settag (Object) is able to add a special tag to a view and then use Gettag () to get the tag.

用处1:多个button设置不同tag,通过tag区分

new OnClickListener() {　　publicvoidonClick(View v) {//获取当前view对应的数字　　int cellId = (Integer) v.getTag();　　cellClicked(cellId, v);　　}　　}　　View v;　　for (int020; i++) {　　v = findViewById(cellIDs[i]);　　v.setOnClickListener(listener);　　v.setTag(i);　　}

用法2:在adapter中的getview实现回收的convertView的复用(这代码高亮搞不好,总是出问题)

@Override public View getView (int position, View Convertview, ViewGroup parent) {Phonedemo Demo;if (convertview==null) {Convertview = Layoutinflater. from(context). Inflate(R. Layout. Cell, null);Demo = new Phonedemo ();Demo. Name= (TextView) convertview. Findviewbyid(R. ID. Name);Demo. number= (TextView) convertview. Findviewbyid(R. ID. number);Demo. IMG= (ImageView) convertview. Findviewbyid(R. ID. ImageView1);Demo. Name. SetText(Data. Get(position). GetName());Demo. number. SetText(Data. Get(position). GetNumber());Demo. IMG. Setimageresource(Data. Get(position). GetId());Using tag to achieve recycling resources Convertview. Settag(demo);}else {//here to get the demo that has been recycled, do not re-create, so you can directly reuse, save resources demo = (Phonedemo) convertview. Gettag();Demo. Name. SetText(Data. Get(position). GetName());Demo. number. SetText(Data. Get(position). GetNumber());Demo. IMG. Setimageresource(Data. Get(position). GetId());} return Convertview;} public static class phonedemo{TextView Name,number;ImageView img;}

用处3:当开关来使用,比如对于手电筒,tag设置为true开启,为false,关闭.

//控制语句if ((Booleanfalse) {            startflashlight();        }else{            stopflashlight();        }

protected void Startflashlight() {//Use transitiondrawable to control the animation, that is, flashlight.xml this fileTransitiondrawable drawable = (transitiondrawable) flashlight.getdrawable ();//Control transition time 200 msDrawable.starttransition ( $);//Set identity, if open, then tag is trueFlashlight.settag (true);/ * * Start opening the camera below, then process the image into the background, then set the Flash to open * /        Try{/* * The communication between camera and its components is associated with the parameter parmeters, the camera can get the current state parameter * and then set the new parameter by setparameters */Mcamera = Camera.open ();//Open camera            intTexttrueid =0;I don't know what it is yet.Mcamera.setpreviewtexture (NewSurfacetexture (Texttrueid));            Mcamera.startpreview (); Mparaters = Mcamera.getparameters ();//Set turn on Flash, and lightMparaters.setflashmode (Parameters.flash_mode_torch);        Mcamera.setparameters (mparaters); }Catch(Exception e) {        }    }/ * * Control the closing of the flash * /    protected void Stopflashlight() {transitiondrawable drawable = (transitiondrawable) flashlight.getdrawable ();if((Boolean) Flashlight.gettag ()) {Drawable.reversetransition ( $); Flashlight.settag (false);if(Mcamera! =NULL) {mparaters = Mcamera.getparameters ();                Mparaters.setflashmode (Parameters.flash_mode_off);                Mcamera.setparameters (mparaters); Mcamera.stoppreview ();//Stop previewingMcamera.release ();//Release resources, or you won't be open next timeMcamera =NULL;//set to NULL for garbage collection mechanism recovery as soon as possible}        }    }

上面三个例子都挺常用的,tag的妙用还是能节省不少代码的,对于程序美观性还是有不少作用的.

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Android---Gettag () and Settag () magical