SurfaceView and Canvas are combined to achieve simple graphic rendering and animation effects.

SurfaceView is a classic in Android. It can implement all the functions required for two-dimensional animation. If you like animation, you can learn it in depth. Today we will start with this article, first understand the animation effect of SurfaceView.

1. A simple small example:

1) MySurfaceView. java

Package com. example. l0904_surfaceview;/*** use the combination of SurfaceView and Canvas to complete * simple animation effect */import java. util. timer; import java. util. timerTask; import android. content. context; import android. graphics. canvas; import android. graphics. color; import android. graphics. paint; import android. view. surfaceHolder; import android. view. surfaceView; // inherits the SurfaceView parent class and implements SurfaceView. callback interface public class MySurfaceView extends Surf AceView implements SurfaceHolder. Callback {// create the Paint brush object private paint Paint = new Paint (); // defines the Timer tool, which is used to schedule the execution of specified tasks in a background thread. It can plan to execute a task once or repeatedly. Private Timer timer; // an abstract class of TimerTask. Its subclass represents a task private TimerTask task that can be scheduled by Timer; // define and initialize the coordinates of the image to be painted. private float x = 0; private float y = 0; private float speedx = 50; private float speedy = 50; // define and initialize the change volume of coordinate movement private float addx = 2; private float addy = 2; /*** SurfaceView constructor * specifies the color of the paint brush to be initialized * @ param context */public MySurfaceView (Context context) {super (context); paint. setColor (Color. BLUE); getHolder (). addCallback (this);}/*** plotting method, in which the specific process is completed */public void draw () {// lock the Canvas canvas = getHolder (). lockCanvas (); // initialize the canvas. drawColor (Color. WHITE); // draw the image. A rectangular canvas is drawn here. drawRect (x, y, speedx + x, speedy + y, paint); x + = addx; y + = addy; // The following is the moving path of the rectangle. if (x <0) {// if the left boundary coordinate of the image exceeds the left screen, move addx = Math to the right. abs (addx);} if (x> getWidth ()-speedx) {// if the right boundary coordinate of the image exceeds the width of the screen, move addx =-Math to the left. abs (addx);} if (y <0) {addy = Math. abs (addy);} if (y> getHeight ()-speedy) {addy =-Math. abs (addy);} // unlock the canvas getHolder (). unlockCanvasAndPost (canvas);}/*** start the timer background thread */public void startTimer () {Timer = new timer (); task = new TimerTask () {@ Override public void run () {// call the drawing method draw () ;}}in the timer thread; // set the timer to start this task every 0.1 seconds, implement the animation effect timer. schedule (task, 100,100);}/*** Method for stopping the timer thread */public void stopTimer () {timer. cancel ();}/*** the following method must be rewritten */@ Override public void surfaceCreated (SurfaceHolder holder) {// start the thread startTimer () ;}@ Override public void surfaceChanged (SurfaceHolder holder, int format, int width, int height) after SurfaceView is created) {}@ Override public void surfaceDestroyed (SurfaceHolder holder) {// The thread stopTimer () must be terminated before the SurfaceView is destroyed ();}}

2) MainActivity. java

Package com. example. l0904_surfaceview; import android. app. activity; import android. OS. bundle; public class MainActivity extends Activity {@ Override protected void onCreate (Bundle savedInstanceState) {super. onCreate (savedInstanceState); // sets the view setContentView (new MySurfaceView (this ));}}

3) running effect:

650) this. width = 650; "src =" http://www.bkjia.com/uploads/allimg/131228/1020101F8-0.jpg "style =" float: none; "title =" Capture. JPG "/>

650) this. width = 650; "src =" http://www.bkjia.com/uploads/allimg/131228/1020105394-1.jpg "style =" float: none; "title =" Capture 1.JPG"/>

In this way, the effect is not obvious. We can track the coordinates of a specific point:

650) this. width = 650; "src =" http://www.bkjia.com/uploads/allimg/131228/1020105348-2.jpg "style =" float: none; "title =" Capture. JPG "/>

.

.

.

650) this. width = 650; "src =" http://www.bkjia.com/uploads/allimg/131228/1020104J8-3.jpg "style =" float: none; "title =" Capture 1.JPG"/>

2. Use SurfaceView to implement a well-known screen protection effect-random bubble.

1) MySurfaceView. java

Package com. example. l0904_collection; import java. util. timer; import java. util. timerTask; import android. content. context; import android. graphics. canvas; import android. graphics. color; import android. graphics. paint; import android. view. surfaceHolder; import android. view. surfaceView; public class MySurfaceView extends SurfaceView implements SurfaceHolder. callback {private Paint paint = new Paint (); private Timer timer; private TimerTask task; private Bolls bolls; public MySurfaceView (Context context) {super (context); paint. setColor (Color. YELLOW); getHolder (). addCallback (this);} public void draw () {Canvas canvas = getHolder (). lockCanvas (); // lock the canvas // draw a graphic canvas. drawColor (Color. WHITE); // initialize the canvas for (int I = 0; I <20; I ++) {bolls = new Bolls (this); canvas. drawCircle (bolls. getCx (), bolls. getCy (), bolls. getRadius (), paint); bolls. draw ();} getHolder (). unlockCanvasAndPost (canvas); // unlock canvas} public void startTimer () {timer = new Timer (); task = new TimerTask () {@ Override public void run () {draw () ;}}; timer. schedule (task, 100,100);} public void stopTimer () {timer. cancel () ;}@ Override public void surfaceCreated (SurfaceHolder holder) {startTimer () ;}@ Override public void surfaceChanged (SurfaceHolder holder, int format, int width, int height) {}@ Override public void surfaceDestroyed (SurfaceHolder holder) {stopTimer ();}}

2) Bolls. java

package com.example.l0904_collection;public class Bolls {    private float cx;    private float cy;    private float radius;    private int addx;    private int addy;    private int addRadius;    MySurfaceView view;                                          public Bolls(MySurfaceView view){        this.view=view;        cx=(float) (Math.random()*300);        cy=(float) (Math.random()*450);        radius=(float) (Math.random()*30);        addx=(int) (Math.random()*10);        addy=(int) (Math.random()*10);        addRadius=(int) (Math.random()*10);    }                                          public float getCx() {        return cx;    }    public void setCx(float cx) {        this.cx = cx;    }    public float getCy() {        return cy;    }    public void setCy(float cy) {        this.cy = cy;    }    public float getRadius() {        return radius;    }    public void setRadius(float radius) {        this.radius = radius;    }    public void draw(){        cx += addx;        cy += addy;        radius+=addRadius;        if (cx < radius) {            addx = Math.abs(addx);        }        if (cx > view.getWidth() - radius) {            addx = -Math.abs(addx);        }        if (cy < radius) {            addy = Math.abs(addy);        }        if (cy > view.getHeight() -radius) {            addy = -Math.abs(addy);        }    }}

3) MainActivity. java

package com.example.l0904_collection;import android.app.Activity;import android.os.Bundle;public class MainActivity extends Activity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(new MySurfaceView(this));    }}

(4) Running Effect

650) this. width = 650; "src =" http://www.bkjia.com/uploads/allimg/131228/1020104091-4.jpg "style =" float: none; "title =" Capture. JPG "/>

650) this. width = 650; "src =" http://www.bkjia.com/uploads/allimg/131228/1020103421-5.jpg "style =" float: none; "title =" Capture 1.JPG"/>

This article is from the MySpace blog, please be sure to keep this source http://wangzhaoli.blog.51cto.com/7607113/1290355