Android简明开发教程十六：Button 画刷示例-白红宇

Android简明开发教程十六：Button 画刷示例

阅读量：5856 次

发布时间：2019-06-19

本文共 5513 字，大约阅读时间需要 18 分钟。

将RadioButton 换成Button ，类似的在res/layout 中新建brush.xml：

<?xml version=”1.0″ encoding=”utf-8″?>

<LinearLayout xmlns:android=””

android:orientation=”vertical”

android:background=”@drawable/white”

android:layout_width=”fill_parent”

android:layout_height=”fill_parent”>

<com.pstreets.graphics2d.GuidebeeGraphics2DView

android:id=”@+id/graphics2dview”

android:layout_weight=”1″

android:layout_width=”fill_parent”

android:layout_height=”wrap_content”/>

<LinearLayout xmlns:android=””

android:layout_width=”wrap_content” android:layout_height=”wrap_content”

android:orientation=”horizontal”

<Button android:text=”Pattern”

android:id=”@+id/btnPattern”

android:layout_width=”wrap_content”

android:textColor=”@color/black”

android:checked=”true”

android:layout_height=”wrap_content”>

</Button>

<Button android:text=”Gradients”

android:id=”@+id/btnGradients”

android:layout_width=”wrap_content”

android:textColor=”@color/black”

android:layout_height=”wrap_content”>

</Button>

</LinearLayout>

修改Brushes.java ,完整代码如下：

                         
public
class
Brushes 
extends
Graphics2DActivity 
   
implements
OnClickListener {  
 
 
private
Button btnPattern; 
 
private
Button btnGradients;  
 
 
public
void
onCreate(Bundle savedInstanceState) { 
  
super
.onCreate(savedInstanceState); 
  
setContentView(R.layout.brush); 
  
graphic2dView = (GuidebeeGraphics2DView) 
      
findViewById(R.id.graphics2dview); 
  
btnPattern = (Button) findViewById(R.id.btnPattern); 
  
btnGradients = (Button) findViewById(R.id.btnGradients); 
  
btnPattern.setOnClickListener(
this
); 
  
btnGradients.setOnClickListener(
this
); 
 
}  
 
 
@Override
 
protected
void
drawImage() { 
  
drawPatterns();  
 
 
}  
 
 
@Override
 
public
void
onClick(View view) { 
  
if
(view == btnPattern) { 
   
drawPatterns(); 
  
} 
else
{ 
   
drawGradient(); 
  
} 
  
graphic2dView.refreshCanvas();  
 
 
}  
 
 
private
void
drawPatterns() { 
  
TextureBrush brush1; 
  
TextureBrush brush2; 
  
TextureBrush brush3;  
 
  
AffineTransform matrix1 = 
new
AffineTransform(); 
  
AffineTransform matrix2 = 
new
AffineTransform(); 
  
Bitmap bitmap 
    
= BitmapFactory.decodeResource(getResources(), 
    
R.drawable.brick); 
  
int
[] rgbData = 
new
int
[bitmap.getHeight() 
                          
* bitmap.getWidth()]; 
  
bitmap.getPixels(rgbData, 
0
, bitmap.getWidth(), 
0
, 
0
, 
    
bitmap.getWidth(), bitmap.getHeight()); 
  
brush1 = 
new
TextureBrush(rgbData, bitmap.getWidth(), 
    
bitmap.getHeight());  
 
  
bitmap = BitmapFactory.decodeResource(getResources(), 
    
R.drawable.bird); 
  
rgbData = 
new
int
[bitmap.getHeight() * bitmap.getWidth()]; 
  
bitmap.getPixels(rgbData, 
0
, bitmap.getWidth(), 
0
, 
0
, 
    
bitmap.getWidth(), bitmap.getHeight()); 
  
brush2 = 
new
TextureBrush(rgbData, bitmap.getWidth(), 
    
bitmap.getHeight()); 
  
brush3 = 
new
TextureBrush(rgbData, bitmap.getWidth(), 
    
bitmap.getHeight(), 
127
); 
  
matrix2.translate(
50
, 
50
); 
  
// Clear the canvas with white color. 
  
graphics2D.clear(Color.WHITE); 
  
graphics2D.setAffineTransform(matrix1); 
  
graphics2D.fillRectangle(brush1, 
     
new
Rectangle(
20
, 
50
, 
100
, 
100
)); 
  
graphics2D.fillOval(brush2, 
10
, 
10
, 
80
, 
80
); 
  
graphics2D.setAffineTransform(matrix2); 
  
graphics2D.fillOval(brush3, 
10
, 
10
, 
80
, 
80
);  
 
 
}  
 
 
private
void
drawGradient() { 
  
/* The linear gradient color */ 
  
LinearGradientBrush brush1; 
  
/* The radial gradient color */ 
  
RadialGradientBrush brush2; 
  
/* The second radial gradient color */
  
RadialGradientBrush brush3;  
 
  
char
[] engText = 
"Brush"
.toCharArray();  
 
  
FontEx font = FontEx.getSystemFont();  
 
  
int
fontSize = 
44
; 
  
int
X = 
15
; 
  
int
Y = 
50
; 
  
int
[] fractions = 
new
int
[] { 
13
, 
242
}; 
  
Color[] colors = 
new
Color[] { 
new
Color(
0xffff6600
), 
    
new
Color(
0xffffff66
) }; 
  
brush1 = 
new
LinearGradientBrush(
50
, 
50
, 
150
, 
125
, 
    
fractions, colors, 
    
Brush.NO_CYCLE);  
 
  
fractions = 
new
int
[] { 
13
, 
128
, 
255
}; 
  
colors = 
new
Color[] { 
new
Color(
0xffff6600
), 
    
new
Color(
0xffffff66
), 
    
new
Color(
0xffff6600
) }; 
  
brush2 = 
new
RadialGradientBrush(
90
, 
100
, 
50
, 
    
fractions, colors);  
 
  
fractions = 
new
int
[] { 
0
, 
255
}; 
  
colors = 
new
Color[] { 
new
Color(
0xFFFFFF00
), 
    
new
Color(
0xFF000000
) }; 
  
brush3 = 
new
RadialGradientBrush(
50
, 
50
, 
100
, 
    
fractions, colors); 
  
// Clear the canvas with white color. 
  
graphics2D.clear(Color.white); 
  
graphics2D.fillRectangle(brush1, 
    
new
Rectangle(
10
, 
75
, 
120
, 
80
));  
 
  
Pen pen = 
new
Pen(brush2, 
8
); 
  
graphics2D.drawOval(pen, 
20
, 
60
, 
100
, 
50
); 
  
graphics2D.setDefaultBrush(brush3); 
  
pen = 
new
Pen(brush2, 
2
); 
  
graphics2D.setDefaultPen(pen); 
  
graphics2D.drawChars(font, fontSize, engText, 
0
, 
    
engText.length, X, Y); 
 
}  
 
}
        
      

介绍了RadioButton和Button 后，这时应该对使用Android提供的控件的用法有了基本的认识。控件提供了onClick(),onLongClick(),onFocusChange(),onKey(),onTouch(),onCreateContextMenu()等多种事件以相应用户。用多种方法来处理用户事件。一种是示例代码同过Activity实现OnClickListener接口，再有是采用如下代码为Button支持事件处理方法：

                         
// Create an anonymous implementation of OnClickListenerprivate 
OnClickListener mCorkyListener = 
new
OnClickListener() {    
   
public
void
onClick(View v) {      
   
// do something when the button is clicked   
   
} 
}; 
 
protected
void
onCreate(Bundle savedValues) {    
   
...   
   
// Capture our button from layout    
   
Button button = (Button)findViewById(R.id.corky);    
   
// Register the onClick listener with the implementation above   
   
button.setOnClickListener(mCorkyListener);   
   
... 
 
}

在创建自定义控件时，也可以重载onKeyDown(int, KeyEvent),onKeyUp(int, KeyEvent) ,onTouchEvent(MotionEvent)等来处理用户事件。

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