Android Paint Canvar

Android Paint Canvar

Recently I have been studying custom controls and encountered geometric drawing. Here I will post a common example:

① First code in the main Activity:

Package com. example. mycustomwidget;


Import android. app. Activity;
Import android. content. Context;
Import android. graphics. Canvas;
Import android. graphics. Color;
Import android. graphics. Paint;
Import android. graphics. RectF;
Import android. OS. Bundle;
Import android. util. AttributeSet;
Import android. view. View;


Public class MainActivity extends Activity {


@ Override
Protected void onCreate (Bundle savedInstanceState ){
Super. onCreate (savedInstanceState );
MyCustomView myView = new MyCustomView (MainActivity. this );
SetContentView (myView );
}
}

 

 

② Code in MyCustomView:

Package com. example. mycustomwidget;


Import android. content. Context;
Import android. graphics. Canvas;
Import android. graphics. Color;
Import android. graphics. Paint;
Import android. graphics. Rect;
Import android. graphics. RectF;
Import android. util. AttributeSet;
Import android. view. View;


Public class MyCustomView extends View {


Public MyCustomView (Context context, AttributeSet attrs ){
Super (context, attrs );
// TODO Auto-generated constructor stub
}




Public MyCustomView (Context context, AttributeSet attrs, int defStyleAttr ){
Super (context, attrs, defStyleAttr );
// TODO Auto-generated constructor stub
}






Public MyCustomView (Context context ){
Super (context );
// TODO Auto-generated constructor stub
}






@ Override
Protected void onDraw (Canvas canvas ){
// TODO Auto-generated method stub
Super. onDraw (canvas );
// Set the canvas color
Canvas. drawColor (Color. BLUE );

// ------------------------------- ① Draw a hollow square --------------------------------
// Create a paint brush
Paint mPaint = new Paint ();
// Set the paint brush to hollow
MPaint. setStyle (Paint. Style. STROKE );
// Set the painting color
MPaint. setColor (Color. RED );
// Set the paint width
MPaint. setStrokeWidth (10 );
/**
* Create a rectangle
* First parameter: X axis coordinate of the Left vertex of the rectangle
* Second parameter: Y axis of the Left vertex of the rectangle
* Third parameter: X-axis coordinate of the vertex in the lower right corner of the rectangle
* Fourth parameter: Y axis of the vertex in the lower right corner of the rectangle
*/
Rect mRect = new Rect (10, 10, 50, 50 );
// Start to draw a rectangle
Canvas. drawRect (mRect, mPaint );

// ------------------------------- ② Draw a solid square --------------------------------
// Set the paint brush to solid.
MPaint. setStyle (Paint. Style. FILL );
// Reset the rectangle size
MRect. set (60, 60,100,100 );
Canvas. drawRect (mRect, mPaint );

// ------------------------------- ③ Draw a hollow rectangle --------------------------------
// Set the width of the paint brush
MPaint. setStrokeWidth (2 );
MPaint. setStyle (Paint. Style. STROKE );
MRect. set (70,110,140,140 );
Canvas. drawRect (mRect, mPaint );

// ------------------------------- ④ Draw a hollow circle --------------------------------
// Eliminate the Sawtooth
MPaint. setAntiAlias (true );
/**
* Draw a hollow circle
* First parameter: X-axis coordinate of the center
* Second parameter: Y-axis coordinate of the center
* Third parameter: circle radius
* Fourth parameter: paint brush
*/
Canvas. drawCircle (180,180, 20, mPaint );

// ------------------------------- ⑤ Draw a solid circle --------------------------------
MPaint. setStyle (Paint. Style. FILL );
Canvas. drawCircle (230,220, 20, mPaint );

// ------------------------------- Draw a solid slice section --------------------------------
// Draw a rectangle first
RectF oval = new RectF (240,240,300,300 );
/**
* Draw a solid slice
* First parameter: a rectangle that defines the size of the slice.
* Second parameter: Start angle of the slice
* Third parameter: angle to be drawn
* Indicates whether the fourth parameter contains a circle (true is included, which is generally used to draw a slice; false is not included, and generally used to draw an arc)
* Fourth parameter: paint brush
*/
Canvas. drawArc (oval, 0, 40, true, mPaint );

// ------------------------------- 7 draw a hollow slice --------------------------------
MPaint. setStyle (Paint. Style. STROKE );
Oval. set (290,290,350,350 );
Canvas. drawArc (oval, 0, 60, true, mPaint );

// ------------------------------- Draw an arc section --------------------------------
Oval. set (360,360,400,400 );
Canvas. drawArc (oval, 0, 70, false, mPaint );

// ------------------------------- Draw a circle --------------------------------
Oval. set (360,360,400,400 );
Canvas. drawRect (oval, mPaint );
Canvas. drawArc (oval, 0,360, false, mPaint );
}


}