Customizing view drawing images and moving fonts

Custom view is often encountered in development, such as the effect of a marquee, or customizing a carousel to show the percentage of the download progress. Write down the implementation today, the following is the source section:

Mainactivity: no change.

Import Android.app.activity;import Android.os.bundle;public class Mainactivity extends Activity {@Override protecte        d void OnCreate (Bundle savedinstancestate) {super.oncreate (savedinstancestate);    Setcontentview (R.layout.activity_main); }}

Main layout: adds only one custom view

<relativelayout xmlns:android= "http://schemas.android.com/apk/res/android" android:layout_width= "match_parent "android:layout_height=" match_parent "> <com.example.myview.mineview android:layout_width=" Wrap_conten T "android:layout_height=" wrap_content "> </com.example.myview.MineView></RelativeLayout>

Custom View:

Import java.util.random;import android.content.context;import android.graphics.canvas;import  android.graphics.paint;import android.graphics.rectf;import android.os.systemclock;import  android.util.attributeset;import android.view.view;public class mineview extends  View {    /**     *  x coordinate of font movement       */    private int rx = 0;    /**      *  Brush Tool      */    private paint  paint;    /**     *  creating thread objects for looping deferred execution commands       */    private MyThread t;    /**      * 0 means that the left,60 of the circle represents the top,100 of the Circle, which represents the right,160 of the circle, the bottom     */     private  RECTF RECTF = NEW RECTF (0, 60, 100, 160);    /**      *  indicates interval angle      */    private  float sweepangle;    /**     *  creating random Number Objects       */    private Random random;    /**      * isdestroy Indicates whether the activity has ended      */     private boolean isdestroy = false;    public mineview ( Context context, attributeset attrs)  {         Super (CONTEXT, ATTRS);         system.out.println ("constructor");         paint = new paint ();         random = nEw random ();         //anti-aliasing, otherwise the image will be difficult to see          paint.setantialias (True);        if  (t ==  null)  {            t = new  mythread ();             t.start ();         }    }    public  Mineview (Context context)  {        super (Context);         system.out.println ("constructor");         paint = new paint ();         paint.setantialias ( true);        if  (t == null)  {         &nbsP;   t = new mythread ();             t.start ();        }    }      @Override     protected void ondraw (Canvas canvas)  {         super.ondraw (Canvas);         paint.settextsize (+);         // rx represents the x-coordinate of a moving font          canvas.drawtext ("Mobile Font",  rx, 30, paint);         // RECTF represents the Circle object, 0 represents the starting angle, sweepangle represents the interval angle, and true and false indicate how the process is drawn, Paint represents the Brush object         canvas.drawarc (Rectf, 0, sweepangle,  true, paint);     }    class mythread extends  Thread {         @Override         public void run ()  {            super.run ();             while  (True)  {                 rx += 5;                 //  If the font moves out of the screen, let the font start from scratch                  if  (rx  > getwidth ())  {                     rx =  (int)   (0 - paint.measuretext ("Mobile Font"));                 }                 sweepangle += 5;                 //  if the angle is greater than 360, let the circle start from 0 degrees to redraw                  if  (SweepAngle  > 360)  {                     sweepAngle = 0;                 }                 //  let colors choose from 0-255 randomly                  int r = random.nextint (;  )               int g =  Random.nextint (  &NB);sp;             int b =  Random.nextint (;               )  //  respectively: Transparency (0~255), red, green, blue                  paint.setargb (255, r, g, b);                 /**                  *  determines if activity has exited and Isdestroy is true if exiting. Then immediately let the thread object and the Brush object be empty, and break,                  *  Otherwise it will cause a memory overflow, this method must be used here, otherwise it will cause a bug with null pointers.                  */                 if  (Isdestroy)  {                     if  (t != null)  {                          t = null;                     }                     if  (paint != null)  {                          paint = null;                     }                     break;                 }                 //  Sleep                  systemclock.sleep (;           )      //  allows the OnDraw method to be re-executed                  postinvalidate ();                 // invalidate (); sub-thread invalid, to use the main thread              }        }     }    /**     *  This method is called when the window is destroyed to close the resource       */     @Override     protected void ondetachedfromwindow ()  {         super.ondetachedfromwindow ();         isdestroy = true;        system.out.println (" Ondetachedfromwindow ");     }}

running effect: running up is dynamic, I will not upload dynamic effects, want to see the effect of their own run up on it.

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Note: Here the marquee effect is just a very stupid way, there is a simpler way, I will introduce later!

This article is from the "Mobile Platform Development" blog, make sure to keep this source http://liuxudong1001.blog.51cto.com/10877072/1726020

Customizing view drawing images and moving fonts