在随机地图中随机绘制随机圈子Android

Question

我在这个任务上取得了很多进展。每次点击一个按钮（圆形）后，最终产品需要在随机颜色/随机大小/随机位置添加一个圆圈。我有另一个按钮（清除），需要清除画布。这是我现在面临的两个问题。我的圈子没有显示在随机位置。他们都从屏幕的左上角开始。第二个问题是我不知道如何让我清晰的按钮工作。其他一切都在工作，随机圆圈大小的随机圆圈颜色。 （因为你有高分辨率的设备最有可能的），你必须让与和视图的高度来绘制你的圈子就可以随机

package com.example.randomcircles; 

import android.annotation.SuppressLint; 
import android.app.Activity; 
import android.graphics.Canvas; 
import android.graphics.Color; 
import android.graphics.Paint; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.Button; 
import android.widget.FrameLayout; 
import android.widget.FrameLayout.LayoutParams; 

public class DisplayRandomCircles extends Activity 
{ 
FrameLayout f1; 
@Override 
public void onCreate(Bundle b) 
{ 
    super.onCreate(b); 
    setContentView(R.layout.activity_display_random_circles); 
    Button btn1 = (Button) findViewById(R.id.btn1); 
    Button btn2 = (Button) findViewById(R.id.btn2); 
    f1 = (FrameLayout) findViewById(R.id.frame); 


} 
@SuppressLint("WrongCall") 
public void doit(View v) 
{ 

    int rand = (int) (Math.random() * 60); 
    switch (v.getId()) 
    { 
     case (R.id.btn1): 
      DrawCircle c = new DrawCircle(getApplicationContext()); 
      f1.addView(c); 
      break; 

     case (R.id.btn2): 
      DrawCircle d = new DrawCircle(getApplicationContext()); 
      f1.addView(d); 
      break; 
    } 
} 
} 

package com.example.randomcircles; 

import java.util.Random; 

import android.annotation.SuppressLint; 
import android.content.Context; 
import android.graphics.Canvas; 
import android.graphics.Color; 
import android.graphics.Paint; 
import android.view.View; 

public class DrawCircle extends View 
{ 
int red = (int) (Math.random() * 255); 
int green = (int) (Math.random() * 255); 
int blue = (int) (Math.random() * 255); 
public DrawCircle(Context con) 
{ 
    super(con); 
} 
@SuppressLint("DrawAllocation") 
@Override 
public void onDraw(Canvas c) 
{ 
    super.onDraw(c); 
    int color = Color.rgb(red, green, blue); 
    int rand = (int)(Math.random() * 200); 
    Paint p = new Paint(Paint.ANTI_ALIAS_FLAG); 
    p.setAntiAlias(true); 
    p.setStyle(Paint.Style.STROKE); 
    p.setStrokeWidth(100); 
    p.setColor(color); 
    p.setStyle(Paint.Style.FILL); 
    c.drawCircle(rand, rand, rand, p); 
    clear(c); 

} 
public void clear(Canvas c) 
{ 
    c.drawColor(Color.TRANSPARENT); 
} 
public void drawColor(int transparent) { 
    // TODO Auto-generated method stub 

} 
} 

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:orientation="vertical" > 

<FrameLayout 
    android:id="@+id/frame" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:layout_weight=".75" 
    android:orientation="vertical" > 


</FrameLayout> 

<LinearLayout 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:layout_weight=".25" 
    android:gravity="bottom|center" 
    android:orientation="horizontal" > 

    <Button 
     android:id="@+id/btn1" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_gravity="start|bottom" 
     android:layout_weight=".50" 
     android:onClick="doit" 
     android:text="@string/Circle" /> 

    <Button 
     android:id="@+id/btn2" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_weight=".50" 
     android:layout_gravity="end|bottom" 
     android:onClick="doit" 
     android:text="@string/Clear" /> 
</LinearLayout> 

</LinearLayout> 

Answer 1

你的随机函数不能有效地借鉴了当前视图圈。

int minRadius = 100; 
    Random random = new Random();//define this outside you onDraw fucntion 
    int w = getWidth(); 
    int h = getHeight(); 

    int randX = random.nextInt(w); 
    int randY = random.nextInt(h); 
    int randR = minRadius + random.nextInt(100); 
    ... 
    c.drawCircle(randX, randY, randR, p); 

也重置您对您绘制颜色整个画布

canvas.drawColor(Color.WHITLE);