Simple example of SurfaceView usage in Android

This article gives an example of SurfaceView usage in Android. To share for your reference, the details are as follows:

Here is a small program that USES SurfaceView to draw a circle on the screen. You can change the position of the circle by pressing the arrow key and touching the screen

Code:

Activity:

package com.view; 
import android.app.Activity; 
import android.os.Bundle; 
import android.view.Window; 
import android.view.WindowManager; 
public class MainActivity extends Activity { 
   /** Called when the activity is first created. */ 
   @Override 
   public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     //  Hidden status bar  
     this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, 
         WindowManager.LayoutParams.FLAG_FULLSCREEN); 
     //  the Activity Remove the title of  
     requestWindowFeature(Window.FEATURE_NO_TITLE); 
     //  Set the layout  
     this.setContentView(new MySurfaceView(this)); 
   } 
}

SurfaceView:

package com.view; 
import android.content.Context; 
import android.graphics.Canvas; 
import android.graphics.Color; 
import android.graphics.Paint; 
import android.view.KeyEvent; 
import android.view.MotionEvent; 
import android.view.SurfaceHolder; 
import android.view.SurfaceHolder.Callback; 
import android.view.SurfaceView; 
public class MySurfaceView extends SurfaceView implements Runnable, Callback {
   private SurfaceHolder mHolder; //  Used to control the SurfaceView 
   private Thread t; //  The statement 1 A thread  
   private boolean flag; //  A thread running identity used to control the thread  
   private Canvas mCanvas; //  The statement 1 A canvas  
   private Paint p; //  The statement 1 The brush  
   private int x = 50, y = 50, r = 10; //  The coordinates and the radius of the circle  
   public MySurfaceView(Context context) { 
     super(context); 
     mHolder = getHolder(); //  To obtain SurfaceHolder object  
     mHolder.addCallback(this); //  for SurfaceView Add status monitoring  
     p = new Paint(); //  create 1 Brush objects  
     p.setColor(Color.WHITE); //  Set the color of the brush to white  
     setFocusable(true); //  Set the focus  
   } 
   /** 
   *  The custom 1 Five ways, paint on the canvas 1 A round  
   */ 
   public void Draw() { 
     mCanvas = mHolder.lockCanvas(); //  Get the canvas object and start painting on the canvas  
     mCanvas.drawRGB(0, 0, 0); //  Fill the canvas with black  
     mCanvas.drawCircle(x, y, r, p); //  draw 1 A round  
     mHolder.unlockCanvasAndPost(mCanvas); //  Finish drawing and display the canvas on the screen  
   } 
   /** 
   *  when SurfaceView This function is called when it is created  
   */ 
   @Override 
   public void surfaceCreated(SurfaceHolder holder) { 
     t = new Thread(this); //  create 1 Thread objects  
     flag = true; //  Set the thread running identity to true 
     t.start(); //  Starting a thread  
   } 
   /** 
   *  when SurfaceView This function is called when the view of  
   */ 
   @Override 
   public void surfaceChanged(SurfaceHolder holder, int format, int width, 
       int height) { 
   } 
   /** 
   *  when SurfaceView When destroyed, this function is called  
   */ 
   @Override 
   public void surfaceDestroyed(SurfaceHolder holder) { 
     flag = false; //  Set the thread running identity to false 
   } 
   /** 
   *  Called when the screen is touched  
   */ 
   @Override 
   public boolean onTouchEvent(MotionEvent event) { 
     x = (int) event.getX(); //  Gets the corresponding screen when touched X Axis coordinates  
     y = (int) event.getY(); //  Gets the corresponding screen when touched Y Axis coordinates  
     return true; 
   } 
   /** 
   *  Called when the user presses a key  
   */ 
   @Override 
   public boolean onKeyDown(int keyCode, KeyEvent event) { 
     if(keyCode == KeyEvent.KEYCODE_DPAD_UP){  // When the user clicks the ↑ button  
       y--;  // Set up the Y Axis coordinate reduction 1 
     } 
     return super.onKeyDown(keyCode, event); 
   } 
   @Override 
   public void run() { 
     while (flag) { 
       Draw(); //  Call the custom draw method  
       try { 
         Thread.sleep(50); //  Let the thread rest 50 ms  
       } catch (InterruptedException e) { 
         e.printStackTrace(); 
       } 
     } 
   } 
}

MySurfaceView first inherited SurfaceView and then implemented the Runnable and Callback interfaces

Rewritten run method of Runnable and surfaceCreated(SurfaceHolder holder), surfaceChanged(SurfaceHolder holder, int format, int width,int height), surfaceDestroyed(SurfaceHolder holder) method of Callback,

Also implemented onTouchEvent(MotionEvent event), onKeyDown(int keyCode, KeyEvent event) method to, detailed in the code has been commented.

I hope this article is helpful for Android programming.