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：
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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：
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// 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。
