Android简明开发教程十六：Button 画刷示例

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=”http://schemas.android.com/apk/res/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=”http://schemas.android.com/apk/res/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>

</LinearLayout>

修改Brushes.java ,完整代码如下：

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 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：

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 // 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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