Android SurfaceView Sketchpad Operation

This article example for everyone to share the Android SurfaceView drawing board operation of the specific code, for your reference, the specific content is as follows

Drawing board-drawing path

package com.example.review.view;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PorterDuff;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

/**
 *  Drawing path on drawing board 
 */
public class HuabanView extends SurfaceView implements SurfaceHolder.Callback {

 private SurfaceHolder surfaceHolder;
 private Path path = new Path();


 public HuabanView(Context context) {
  super(context);
 }

 public HuabanView(Context context, AttributeSet attrs) {
  super(context, attrs);
  surfaceHolder = getHolder();
  surfaceHolder.addCallback(this);// Obtain surfaceview Life cycle of 
 }

 public HuabanView(Context context, AttributeSet attrs, int defStyleAttr) {
  super(context, attrs, defStyleAttr);
 }

 public HuabanView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
  super(context, attrs, defStyleAttr, defStyleRes);
 }

 @Override
 public void surfaceCreated(SurfaceHolder holder) {
  new HuabanThread().start();
 }

 @Override
 public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

 }

 @Override
 public void surfaceDestroyed(SurfaceHolder holder) {

 }

 @Override
 public boolean onTouchEvent(MotionEvent event) {
  float x = event.getX();
  float y = event.getY();
  int action = event.getAction();
  if (action == MotionEvent.ACTION_DOWN) {// Press 
   path.moveTo(x, y);
  } else if (action == MotionEvent.ACTION_MOVE) {// Moving 
   path.lineTo(x, y);
  }
  return true;
 }

 class HuabanThread extends Thread {
  @Override
  public void run() {
   super.run();
   //TODO: Paintbrush 
   Paint paint = new Paint();
   paint.setColor(Color.BLACK);
   paint.setStrokeWidth(20);
   paint.setStyle(Paint.Style.STROKE);
   paint.setAntiAlias(true);
   //TODO: Canvas 
   while (true) {
    Canvas canvas = surfaceHolder.lockCanvas();
    // Avoid null pointers 
    if (canvas == null){
     return;
    }
    canvas.drawColor(Color.WHITE, PorterDuff.Mode.CLEAR);
    canvas.drawColor(Color.WHITE);
    canvas.drawPath(path,paint);
    surfaceHolder.unlockCanvasAndPost(canvas);
   }
  }
 }
 public void close(){
  path.reset();
 }
}

Drawing board-drawing dynamic straight lines

package com.example.review.view;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PorterDuff;
import android.util.AttributeSet;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

/**
 *  Drawing path on drawing board 
 *  Draw a dynamic line 
 */
public class LineView extends SurfaceView implements SurfaceHolder.Callback {

 private SurfaceHolder surfaceHolder;
 private Path path = new Path();
 private int x = 0;

 public LineView(Context context) {
  super(context);
 }

 public LineView(Context context, AttributeSet attrs) {
  super(context, attrs);
  surfaceHolder = getHolder();
  surfaceHolder.addCallback(this);// Obtain surfaceview Life cycle of 
 }

 public LineView(Context context, AttributeSet attrs, int defStyleAttr) {
  super(context, attrs, defStyleAttr);
 }

 public LineView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
  super(context, attrs, defStyleAttr, defStyleRes);
 }

 @Override
 public void surfaceCreated(SurfaceHolder holder) {
  new HuabanThread().start();
 }

 @Override
 public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

 }

 @Override
 public void surfaceDestroyed(SurfaceHolder holder) {

 }

 class HuabanThread extends Thread {
  @Override
  public void run() {
   super.run();
   //TODO: Paintbrush 
   Paint paint = new Paint();
   paint.setColor(Color.BLACK);
   paint.setStrokeWidth(20);
   paint.setStyle(Paint.Style.STROKE);
   paint.setAntiAlias(true);
   //TODO: Canvas 
   while (true) {
    Canvas canvas = surfaceHolder.lockCanvas();
    // Avoid null pointers 
    if (canvas == null){
     return;
    }
    canvas.drawColor(Color.WHITE, PorterDuff.Mode.CLEAR);
    canvas.drawColor(Color.WHITE);
    canvas.drawLine(0,100,x++,100,paint);
    surfaceHolder.unlockCanvasAndPost(canvas);
   }
  }
 }

 public void close(){
  path.reset();
 }

}

Basic graphics

// Circle 
canvas.drawOval(50,100,150,200,paint);
// Semicircle 
canvas.drawArc(500,500,700,700,20,180,true,paint);
// Rectangle 
canvas.drawRect(100,300,250,400,paint);
//3 Angle 
canvas.drawLine(100,450,0,600,paint);
canvas.drawLine(0,600,400,600,paint);
canvas.drawLine(100,450,400,600,paint);
// Trapezoid 
canvas.drawLine(100,700,200,700,paint);
canvas.drawLine(100,700,0,900,paint);
canvas.drawLine(0,900,400,900,paint);
canvas.drawLine(200,700,400,900,paint);

// Text 
canvas.drawText(" Screenshot ",100,1000,paint);