Android 自定义view实例：跟踪手指小球

最新推荐文章于 2022-04-27 10:02:25 发布

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最新推荐文章于 2022-04-27 10:02:25 发布

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本文介绍如何在Android应用中实现自定义视图的绘制，包括创建DrawView类，设置视图的画笔属性，响应触摸事件更新视图位置，并在主菜单中添加选项。

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package com.example.test;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;

public class DrawViewActivity extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.drawView_main);
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

}

package com.ui;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

public class DrawView extends View {

	public float currentX = 40;
	public float currentY = 50;
	
	Paint p = new Paint();
	public DrawView(Context context){
		super(context);
	}
	public DrawView(Context context, AttributeSet set)
	{
		super(context,set);
	}
	
	public void onDraw(Canvas canvas)
	{
		super.onDraw(canvas);
		
		p.setColor(Color.BLACK);
		canvas.drawCircle(currentX, currentY, 15, p);
	}
	
	public boolean onTouchEvent(MotionEvent event)
	{
		currentX = event.getX();
		currentY = event.getY();
		invalidate();
		return true;
	}
}