Android-常用绘图类的基本应用-鼠标点击画圆圈

最新推荐文章于 2022-05-23 17:05:27 发布

原创最新推荐文章于 2022-05-23 17:05:27 发布 · 821 阅读

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#Android #绘图类

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本文介绍了一个简单的Android应用程序，该程序能够在触摸屏幕时实时更新并绘制一系列同心圆，并在圆上添加文字说明。通过监听触摸事件，调整圆的位置，实现动态效果。

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package com.example.drawcircle;

import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.FrameLayout;


public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        FrameLayout fm = (FrameLayout)findViewById(R.id.framelayout1);
        final DrawCircle drawview= new DrawCircle(this);
        
        drawview.setOnTouchListener(new OnTouchListener() {
			
			@Override
			public boolean onTouch(View arg0, MotionEvent arg1) {
				// TODO Auto-generated method stub
				drawview.xpos=arg1.getX();
				drawview.ypos=arg1.getY();
				drawview.invalidate();
				return false;
			}
		});
        
        fm.addView(drawview);
    }

    
    
    

    @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;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
    public class DrawCircle extends View
    {
    	private float xpos,ypos;
    	public DrawCircle(Context context) {
    		super(context);
    		xpos=100;
    		ypos=100;
    		// TODO Auto-generated constructor stub
    	}
    	
    	protected void onDraw(Canvas canvas)
    	{
    		super.onDraw(canvas);
    		Paint paint = new Paint();
    		paint.setColor(Color.BLUE);
    		paint.setStyle(Style.STROKE);//填充样式为描边
    		paint.setStrokeWidth(1);//笔触宽度为5像素
    		canvas.drawCircle(xpos,ypos,50, paint);
    		canvas.drawCircle(xpos,ypos,40, paint);
    		canvas.drawCircle(xpos,ypos,30, paint);
    		canvas.drawCircle(xpos,ypos,20, paint);
    		canvas.drawCircle(xpos,ypos,10, paint);
    		paint.setTextSize(20);
    		canvas.drawText("这是一个地球！",xpos-50,ypos+100,paint);
    	}
    }
}

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/framelayout1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.drawcircle.MainActivity" >

  

</FrameLayout>