在Android开
发中,在Activity中关联视图View是一般使用setContentView方法,该方法一种参数是使用XML资源直接创 建:setContentView
(int layoutResID),指定layout中的一个XML的ID即可,这种方法简单。另一个方法是
setContentView(android.view.View),参数是指定一个视图View对象,这种方法可以使用自定义的视图类。
在一些场合中,需要对View进行一些定制处理,比如获取到Canvas进行图像绘制,需要重载View::onDraw方法,这时需要对View
进行派生一个类,重载所需要的方法,然后使用setContentView(android.view.View)与Activity进行关联,具体代码
举例如下:
- public class temp extends Activity {
-
- @Override
- public void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(new DrawView(this));
- }
-
- private class DrawView extends View {
- private Paint paint;
-
-
-
- public DrawView(Context context) {
- super(context);
- paint = new Paint();
-
- paint.setColor(Color.GREEN);
-
- paint.setTextSize(25);
-
- paint.setAntiAlias(true);
- }
-
- protected void onDraw(Canvas canvas) {
- super.onDraw(canvas);
- canvas.drawText("Hello World", 5, 30, paint);
-
-
- invalidate();
- }
- }
- }
第二个例子,动态绘图
- public class MyAndroidProjectActivity extends Activity {
-
-
-
-
-
-
- static int times = 1;
-
-
- @Override
- public void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(new DrawView(this));
-
- }
- private class DrawView extends View {
- Paint vPaint = new Paint();
- private int i = 0;
- public DrawView(Context context) {
- super(context);
-
- }
-
- protected void onDraw(Canvas canvas) {
- super.onDraw(canvas);
- System.out.println("this run " + (times++) +" times!");
-
-
- vPaint.setColor( 0xff00ffff );
- vPaint.setAntiAlias( true );
- vPaint.setStyle( Paint.Style.STROKE );
-
-
- canvas.drawArc(new RectF(60, 120, 260, 320), 0, i, true, vPaint );
-
-
- if( (i+=10) > 360 )
- i = 0;
-
-
- invalidate();
- }
- }
-
- }
Android编程动态创建视图View的方法,布布扣,bubuko.com
Android编程动态创建视图View的方法
原文:http://www.cnblogs.com/Free-Thinker/p/3694785.html