Android their definition view view

Creating a new view will meet our unique UI needs.

This article describes the development of using the Compass Compass interface to define your own view class tools by inheriting view, in order to gain insight into your own custom views.

Realize:

Source:

Layout file Activity_main (Compassview Inherit view Class):

<framelayout xmlns:android= "http://schemas.android.com/apk/res/android"    xmlns:tools= "http// Schemas.android.com/tools "    android:layout_width=" match_parent "    android:layout_height=" Match_parent "    tools:context= ". Mainactivity ">    <com.professionalandroiddemo6.compassview        android:id=" @+id/compassview "        Android:layout_width= "Match_parent"        android:layout_height= "Match_parent"/></framelayout>

Under the Res/values directory:

String.xml:

<?xml version= "1.0" encoding= "Utf-8"?
><resources>    <string name= "app_name" >ProfessionalAndroidDemo6</string>    <string Name= "action_settings" font = "14sp" >Settings</string>    <string name= "Hello_world" >hello world! </string><string name= "North" >n</string><string name= "East" >e</string><string Name= "South" >s</string><string name= "West" >W</string></resources>

Colors.xml:

<?xml version= "1.0" encoding= "Utf-8"?><resources>    <color name= "Background" > #F555 </color >    <color name= "Maker" > #AFFF </color>    <color name= "text" > #AFFF </color>    < /resources>

code files;

Mainactivity:

Package Com.professionalandroiddemo6;import Android.app.activity;import Android.os.bundle;public class MainActivity Extends Activity {@Overrideprotected void onCreate (Bundle savedinstancestate) {super.oncreate (savedinstancestate); Setcontentview (R.layout.activity_main);}}

Compassview:

Package com.professionalandroiddemo6;/** * Self-defined View-compass interface */import Android.content.context;import Android.content.res.resources;import Android.graphics.canvas;import Android.graphics.paint;import Android.util.attributeset;import Android.view.view;import Android.view.accessibility.accessibilityevent;public Class Compassview extends View {private Paint markerpaint;private paint circlepaint;private paint textpaint;private strin G North, South, east, West;private int textheight;private String dirstring;private float bearing;public void Setbearing (fl Oat _bearing) {bearing = _bearing;sendaccessibilityevent (accessibilityevent.type_view_text_changed);} public float getbearing () {return bearing;} Public Compassview (Context context) {super (context); Initcompassview ();} Public Compassview (context context, AttributeSet Attrs) {Super (context, attrs); Initcompassview ();} Public Compassview (context context, AttributeSet attrs, int defstyleattr) {Super (context, attrs, defstyleattr); Initcompassview ();} Privatevoid Initcompassview () {setfocusable (true); Resources resources = This.getresources (); circlepaint = new Paint (paint.anti_alias_flag); Circlepaint.setcolor ( Resources.getcolor (R.color.background)); Circlepaint.setstrokewidth (1); Circlepaint.setstyle (Paint.Style.FILL_ And_stroke), north = resources.getstring (R.string.north), south = resources.getstring (R.string.south), east = Resources.getstring (r.string.east); west = resources.getstring (r.string.west); textpaint = new Paint (paint.anti_alias _flag); Textpaint.setcolor (Resources.getcolor (R.color.text)); Textpaint.settextsize ((float) 30);//This sets the size of the font that will be displayed.
TextHeight = (int) textpaint.measuretext ("YY"), Markerpaint = new Paint (paint.anti_alias_flag); Markerpaint.setcolor ( Resources.getcolor (R.color.maker));} @Overrideprotected void onmeasure (int widthmeasurespec, int heightmeasurespec) {//Compass is a circle that fills as much space as possible. Sets the measured size by setting the shortest bounds, height, or width. int measuredwidth = measure (widthmeasurespec); int measuredheight = measure (HEIGHTMEASURESPEC); int d = Math.min ( Measuredwidth, Measuredheight); Setmeasureddimension (d, D);} private int measure (int measurespec) {int result = 0;//decodes the measured description int specmode = Measurespec.getmode (measurespec); int SpecS ize = Measurespec.getsize (Measurespec); if (Specmode = = measurespec.unspecified) {//Assuming no bounds are specified, the default return value is 200result = 200;} else {//because you want to populate the available space, always return the entire available boundary result = specsize;} return result;} @Overrideprotected void OnDraw (canvas canvas) {//locates the center of the control. and stores the length of the minimum edge as the radius of the compass.
int mmeasuredwidth = Getmeasuredwidth (), int mmeasuredheight = Getmeasuredheight (); int px = Mmeasuredwidth/2;int py = mMe Asuredheight/2;int radius = math.min (px, py);//Use the Drawcircle method to draw the boundary of the compass character and color it for Beijing. Canvas.drawcircle (px, py, radius, circlepaint), Canvas.save (), Canvas.rotate (-bearing, px, py);//The only thing left to do is draw marks. Rotate the canvas a circle, and draw a marker every 15 degrees, drawing an abbreviation for One Direction every 45 degrees. int textWidth = (int) textpaint.measuretext ("W"), int cardinalx = Px-textwidth/2;int Cardinaly = Py-radius + Textheig ht;//draws a marker every 15 degrees and draws one text for each 45 degrees for (int i = 0; i < i++) {canvas.drawline (px, Py-radius, px, Py-radius +), Markerp aint); Canvas.save () canvas.translate (0, textHeight);//Draw Basic azimuth if (i 6 = = 0) {switch (i) {case 0: {dirstring = North;int a  Rrowy = 2 * textheight;canvas.drawline (px, Arrowy, px-5, 5 * textheight,markerpaint), canvas.drawline (px, arrowy, px + 5, 5 * textheight,markerpaint);} Break;case 6:dirstring = east;break;case 12:dirstring = south;break;case 18:dirstring = west;break;} Canvas.drawtext (dirstring, CardinaLX, Cardinaly, textpaint);} else if (i 3 = = 0) {//Draw text every 45 degrees String angle = string.valueof (i *); float angletextwidth = textpaint.measuretext (angle) ; int angletextx = (int) (PX-ANGLETEXTWIDTH/2); int angletexty = Py-radius + textheight;canvas.drawtext (angle, Anglete XtX, Angletexty, textpaint);} Canvas.restore (); Canvas.rotate (px, py);} Canvas.restore ();} @Overridepublic boolean dispatchpopulateaccessibilityevent (Accessibilityevent event) { Super.dispatchpopulateaccessibilityevent (event), if (Isshown ()) {String bearingstr = string.valueof (bearing); Bearingstr.length () > accessibilityevent.max_text_length) bearingstr = bearingstr.substring (0, Accessibilityevent.max_text_length); Event.gettext (). Add (bearingstr); return true;} return false;}}

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Android their definition view view