Android拖动改变小球位置
Android拖动改变小球位置
1. 引言
在模拟器中按下鼠标并拖动,使小球跟随鼠标的变化而变化。
2. 功能实现
- package com.focus.fishme.web;
- import Android.app.Activity;
- import android.content.Context;
- import android.graphics.Canvas;
- import android.graphics.Color;
- import android.graphics.Paint;
- import android.os.Bundle;
- import android.view.MotionEvent;
- import android.view.View;
- import android.view.Window;
- import android.view.WindowManager;
- public class ScrollBallActivity extends Activity {
- private float x = 100;
- private float y = 100;
- private Ball ball = null;
- @Override
- public void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- requestWindowFeature(Window.FEATURE_NO_TITLE);
- getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
- ball = new Ball(this);
- setContentView(ball);
- }
- @Override
- public boolean onTouchEvent(MotionEvent event) {
- x = event.getX();
- y = event.getY();
- switch(event.getAction()) {
- case MotionEvent.ACTION_DOWN:
- ball.invalidate();
- break;
- case MotionEvent.ACTION_UP:
- ball.invalidate();
- break;
- case MotionEvent.ACTION_MOVE:
- ball.invalidate();
- break;
- }
- return super.onTouchEvent(event);
- }
- class Ball extends View {
- public Ball(Context context) {
- super(context);
- }
- @Override
- protected void onDraw(Canvas canvas) {
- Paint paint = new Paint();
- paint.setColor(Color.GREEN);
- canvas.drawCircle(x, y, 10, paint);
- super.onDraw(canvas);
- }
- }
- }
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