Android 畫圖-圓圈（紅、綠、黃）

畫紅圈

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?xml version="1.0" encoding="utf-8"?

xmlns:android=""

android:shape="oval"

android:useLevel="false"

solid android:color="@color/red" /

? ? android:width="1dp"

? ? android:color="@color/white" /

? ? android:width="20dp"

? ? android:height="20dp" /

/shape

畫黃圈

?xml version="1.0" encoding="utf-8"?

shape xmlns:android=""

android:shape="oval"

android:useLevel="false"

solid android:color="@color/yellow" /

? ? android:width="1dp"

? ? android:color="@color/white" /

? ? android:width="20dp"

? ? android:height="20dp" /

/shape

畫綠圈

?xml version="1.0" encoding="utf-8"?

shape xmlns:android=""

android:shape="oval"

android:useLevel="false"

solid android:color="@color/green" /

? ? android:width="1dp"

? ? android:color="@color/white" /

? ? android:width="20dp"

? ? android:height="20dp" /

/shape

android 里用shape畫圓，怎么填充顏色

Android里面使用shape設(shè)置控件的外形，例如一些圓角、填充的背景顏色、以及一些漸變的效果等，所以設(shè)置填充顏色，可通過設(shè)置shape.xml文件里的如下屬性：

solid?android:color="@color/common_red"?/

將shape文件放到android的button、textview組件上，就可以有填充背景顏色的效果，完整的代碼如下：

1.shape.xml

?xml?version="1.0"?encoding="UTF-8"?

shape?

xmlns:android=""

android:shape="oval"

android:useLevel="false"?

solid?android:color="@color/common_red"?/

padding?

android:left="2dp"?

android:top="1dp"?

android:right="2dp"?

android:bottom="1dp"?/

solid

android:color="@color/common_red"?/

stroke

android:width="1dp"

android:color="@android:color/white"?/

size?android:width="15dp"

android:height="15dp"?/

/shape

2.把以上代碼添加到drawable里面、通過background引用就可以了

TextView

android:id="@?id/message_category_unread_count"

style="@style/comm_text_style_14_aaaaaa"

android:layout_marginLeft="70dp"

android:layout_marginTop="5dp"

android:background="@drawable/shape"

android:gravity="center"

android:textSize="@dimen/text_size_comment_20"

android:text="7"

android:textColor="@android:color/white"?/

效果如下圖：

android 怎么畫一個(gè)圓弧的正方形

public void drawArc(@NonNull RectF oval, float startAngle, float sweepAngle, boolean useCenter,

@NonNull Paint paint) {

drawArc(oval.left, oval.top, oval.right, oval.bottom, startAngle, sweepAngle, useCenter,

paint);

}

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要實(shí)現(xiàn)這個(gè)方法，我們要傳5個(gè)參數(shù)進(jìn)去。

第一個(gè)參數(shù)：RectF oval

oval 參數(shù)的作用是：定義的圓弧的形狀和大小的范圍

/**

* 這是一個(gè)居中的圓

*/

float x = (getWidth() - getHeight() / 2) / 2;

float y = getHeight() / 4;

RectF oval = new RectF( x, y,

getWidth() - x, getHeight() - y);

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oval 參數(shù)的作用是：定義的圓弧的形狀和大小的范圍

第二個(gè)參數(shù)：float startAngle

這個(gè)參數(shù)的作用是設(shè)置圓弧是從哪個(gè)角度來順時(shí)針繪畫的

canvas.drawArc(oval,-90,120,false,mPaint);

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-90

canvas.drawArc(oval,90,110,false,mPaint);

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90

//設(shè)置為-180的時(shí)候也是這樣

canvas.drawArc(oval,180,140,false,mPaint);

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180

//設(shè)置為360的時(shí)候也是這樣

canvas.drawArc(oval,0,140,false,mPaint);

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140

第三個(gè)參數(shù)：float sweepAngle

這個(gè)參數(shù)的作用是設(shè)置圓弧掃過的角度

我們從上面的代碼就可以知道其中的作用了

第四個(gè)參數(shù)：boolean useCenter

android 怎么在屏幕中間畫一個(gè)圓

主要運(yùn)用SurfaceView來實(shí)現(xiàn)在屏幕上畫一個(gè)圓，你可以通過按方向鍵和觸摸屏幕來改變圓的位置代碼： Activitypackage com.view;import android.app.Activity;import android.os.Bundle;import android.view.Window;import android.view.WindowManager;public class MainActivity extends Activity {/** Called when the activity is first created. */@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);// 隱藏狀態(tài)欄this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);// 把Activity的標(biāo)題去掉requestWindowFeature(Window.FEATURE_NO_TITLE);// 設(shè)置布局this.setContentView(new MySurfaceView(this));}}SurfaceViewpackage com.view;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.view.KeyEvent;import android.view.MotionEvent;import android.view.SurfaceHolder;import android.view.SurfaceHolder.Callback;import android.view.SurfaceView;public class MySurfaceView extends SurfaceView implements Runnable, Callback {private SurfaceHolder mHolder; // 用于控制SurfaceViewprivate Thread t; // 聲明一條線程private boolean flag; // 線程運(yùn)行的標(biāo)識(shí)，用于控制線程private Canvas mCanvas; // 聲明一張畫布private Paint p; // 聲明一支畫筆private int x = 50, y = 50, r = 10; // 圓的坐標(biāo)和半徑public MySurfaceView(Context context) {super(context);mHolder = getHolder(); // 獲得SurfaceHolder對(duì)象mHolder.addCallback(this); // 為SurfaceView添加狀態(tài)監(jiān)聽p = new Paint(); // 創(chuàng)建一個(gè)畫筆對(duì)象p.setColor(Color.WHITE); // 設(shè)置畫筆的顏色為白色setFocusable(true); // 設(shè)置焦點(diǎn)}/*** 自定義一個(gè)方法，在畫布上畫一個(gè)圓*/public void Draw() {mCanvas = mHolder.lockCanvas(); // 獲得畫布對(duì)象，開始對(duì)畫布畫畫mCanvas.drawRGB(0, 0, 0); // 把畫布填充為黑色mCanvas.drawCircle(x, y, r, p); // 畫一個(gè)圓mHolder.unlockCanvasAndPost(mCanvas); // 完成畫畫，把畫布顯示在屏幕上}/*** 當(dāng)SurfaceView創(chuàng)建的時(shí)候，調(diào)用此函數(shù)*/@Overridepublic void surfaceCreated(SurfaceHolder holder) {t = new Thread(this); // 創(chuàng)建一個(gè)線程對(duì)象flag = true; // 把線程運(yùn)行的標(biāo)識(shí)設(shè)置成truet.start(); // 啟動(dòng)線程}/*** 當(dāng)SurfaceView的視圖發(fā)生改變的時(shí)候，調(diào)用此函數(shù)*/@Overridepublic void surfaceChanged(SurfaceHolder holder, int format, int width,int height) {}/*** 當(dāng)SurfaceView銷毀的時(shí)候，調(diào)用此函數(shù)*/@Overridepublic void surfaceDestroyed(SurfaceHolder holder) {flag = false; // 把線程運(yùn)行的標(biāo)識(shí)設(shè)置成false}/*** 當(dāng)屏幕被觸摸時(shí)調(diào)用*/@Overridepublic boolean onTouchEvent(MotionEvent event) {x = (int) event.getX(); // 獲得屏幕被觸摸時(shí)對(duì)應(yīng)的X軸坐標(biāo)y = (int) event.getY(); // 獲得屏幕被觸摸時(shí)對(duì)應(yīng)的Y軸坐標(biāo)return true;}/*** 當(dāng)用戶按鍵時(shí)調(diào)用*/@Overridepublic boolean onKeyDown(int keyCode, KeyEvent event) {if(keyCode == KeyEvent.KEYCODE_DPAD_UP){ //當(dāng)用戶點(diǎn)擊↑鍵時(shí)y--; //設(shè)置Y軸坐標(biāo)減1}return super.onKeyDown(keyCode, event);}@Overridepublic void run() {while (flag) {Draw(); // 調(diào)用自定義畫畫方法try {Thread.sleep(50); // 讓線程休息50毫秒} catch (InterruptedException e) {e.printStackTrace();}}}}MySurfaceView首先繼承SurfaceView，然后實(shí)現(xiàn)Runnable和Callback接口重寫了Runnable的run方法和Callback的surfaceCreated(SurfaceHolder holder)，surfaceChanged(SurfaceHolder holder, int format, int width,int height)，surfaceDestroyed(SurfaceHolder holder)方法， 還實(shí)現(xiàn)了onTouchEvent(MotionEvent event)，onKeyDown(int keyCode, KeyEvent event)方法來，詳細(xì)的在代碼里已注釋。

android 怎么畫2層圓環(huán)

Android繪制兩層圓環(huán)，可以使用自定義View，繼承View，重寫里面的Ondraw方法，花兩個(gè)同心圓，示例如下：

package?com.cn.myvdun;??

import?android.content.Context;??

import?android.graphics.Canvas;??

import?android.graphics.Paint;??

import?android.util.AttributeSet;??

import?android.view.View;??

public?class?RingView?extends?View?{??

private?final??Paint?paint;??

private?final?Context?context;??

public?RingView(Context?context)?{??

//?TODO?Auto-generated?constructor?stub??

this(context,?null);??

}??

public?RingView(Context?context,?AttributeSet?attrs)?{??

super(context,?attrs);??

//?TODO?Auto-generated?constructor?stub??

this.context?=?context;??

this.paint?=?new?Paint();??

this.paint.setAntiAlias(true);?//消除鋸齒??

this.paint.setStyle(Paint.Style.STROKE);?//繪制空心圓???

}??

@Override??

protected?void?onDraw(Canvas?canvas)?{??

//?TODO?Auto-generated?method?stub??

int?center?=?getWidth()/2;??

int?innerCircle?=?dip2px(context,?83);?//設(shè)置內(nèi)圓半徑??

int?ringWidth?=?dip2px(context,?5);?//設(shè)置圓環(huán)寬度??

//繪制內(nèi)圓??

this.paint.setARGB(155,?167,?190,?206);??

this.paint.setStrokeWidth(2);??

canvas.drawCircle(center,center,?innerCircle,?this.paint);??

//繪制圓環(huán)??

this.paint.setARGB(255,?212?,225,?233);??

this.paint.setStrokeWidth(ringWidth);??

canvas.drawCircle(center,center,?innerCircle+1+ringWidth/2,?this.paint);??

//繪制外圓??

this.paint.setARGB(155,?167,?190,?206);??

this.paint.setStrokeWidth(2);??

canvas.drawCircle(center,center,?innerCircle+ringWidth,?this.paint);

super.onDraw(canvas);??

}??

}

android canvas.drawcircle 為什么畫不出圓

繪制圓的話,drawcircle需要傳圓心坐標(biāo)和半徑大小/畫筆進(jìn)去,我猜你缺少對(duì)應(yīng)的參數(shù),可以參考如下代碼:

mPaint.setAntiAlias(false); //設(shè)置畫筆為無鋸齒

mPaint.setColor(Color.BLACK); //設(shè)置畫筆顏色

canvas.drawColor(Color.WHITE); //白色背景

mPaint.setStrokeWidth((float) 3.0); //線寬

mPaint.setStyle(Paint.Style.STROKE); //空心效果

canvas.drawCircle(50, 50, 10, mPaint); //繪制圓形

canvas.drawCircle(100, 100, 20, mPaint); //繪制圓形

canvas.drawCircle(150, 150, 30, mPaint); //繪制圓形

canvas.drawCircle(200, 200, 40, mPaint); //繪制圓形

canvas.drawCircle(250, 250, 50, mPaint); //繪制圓形

canvas.drawCircle(300, 300, 60, mPaint); //繪制圓形

canvas.drawCircle(350, 350, 70, mPaint); //繪制圓形