一个关于自定义view的小程序

public class HelloView extends View {
	
	private final String TAG = "MyLog";

	public HelloView(Context context) {
		super(context);
		Log.d(TAG, "HelloView构造方法1");
		Log.d(TAG, "w:" +this.getWidth() +" h:" +this.getHeight());
	}
	
	public HelloView(Context context, AttributeSet attrs) {
		super(context, attrs);
		Log.d(TAG, "HelloView构造方法2");
		Log.d(TAG, "w:" +this.getWidth() +" h:" +this.getHeight());
	}
	
	public HelloView(Context context, AttributeSet attrs, int i) {
		super(context, attrs, i);
		Log.d(TAG, "HelloView构造方法3");
		Log.d(TAG, "w:" +this.getWidth() +" h:" +this.getHeight());
	}
	
	protected void onDraw(Canvas canvas) {
		Log.d(TAG, "HelloView onDraw方法");
		Log.d(TAG, "w:" +this.getWidth() +" h:" +this.getHeight());
		canvas.drawColor(Color.BLUE);
		myUseBitmapDrawable(canvas);
		myUseBitmapFactory(canvas);
		myUseInputStreamandBitmapDrawable(canvas);
		initPaint();
		canvas.drawText("这段文字使用了画笔", 20, 20, paint);
		myEvent();
	}
	
	Paint paint;
	
	public void initPaint() {
		Log.d(TAG, "HelloView paint初始化方法");
		paint = new Paint();
		paint.setColor(Color.GREEN);
		paint.setAntiAlias(true);
		paint.setTextSize(18);
	}
	
	/**
	 * 定义手势识别
	 */
	GestureDetector mGestureDetector;
	
	public void myEvent() {
		mGestureDetector = new GestureDetector(
				new GestureDetector.SimpleOnGestureListener(){
					public boolean onSingleTapUp(MotionEvent e) {
						Log.d(TAG, "g.getX():" +e.getX()+ " e.getY():" +e.getY());
						return true;
					}
		});
	}
	
	public boolean onTouchEvent(MotionEvent event) {
		mGestureDetector.onTouchEvent(event);
		return true;
	}
	
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
		Log.d(TAG, "HelloView onMeasure方法");
		Log.d(TAG, "w:" +this.getWidth() +" h:" +this.getHeight());
		super.onMeasure(widthMeasureSpec, heightMeasureSpec);
	}
	
	public void myUseBitmapFactory(Canvas canvas) {
		Paint paint = new Paint();
		Resources rec = getResources();
		InputStream is = rec.openRawResource(R.drawable.promo_ipad);
		Bitmap bitmap = BitmapFactory.decodeStream(is);
		
//		BitmapFactory.decodeResource(getResources(), R.drawable.promo_ipad);
		
		canvas.drawBitmap(bitmap, 0, 150, paint);
	}
	
	public void myUseBitmapDrawable(Canvas canvas) {
		Paint paint = new Paint();
		Resources rec = getResources();
		BitmapDrawable bitmapDrawable = (BitmapDrawable) rec.getDrawable(R.drawable.promo_ipad);
		Bitmap bitmap = bitmapDrawable.getBitmap();
		canvas.drawBitmap(bitmap, 100, 20, paint);
	}
	
	public void myUseInputStreamandBitmapDrawable(Canvas canvas) {
		Paint paint = new Paint();
		Resources rec = getResources();
		InputStream is = rec.openRawResource(R.drawable.promo_ipad);
		BitmapDrawable bitmapDrawable = new BitmapDrawable(is);
		Bitmap bitmap = bitmapDrawable.getBitmap();
		canvas.drawBitmap(bitmap, 100, 300, paint);
	}
	
}