本文实例为大家分享了Android实现颜色选取圆盘的具体代码，供大家参考，具体内容如下

先看效果图

xml布局

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" > <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="@string/hello" android:id="@+id/tv_rgb"/> <RelativeLayout android:id="@+id/relativeLayout1" android:layout_height="fill_parent" android:layout_width="fill_parent"> <com.myview.ColorPickerView android:id="@+id/cpv" android:layout_width="230dp" android:layout_height="230dp" android:layout_centerInParent="true" android:scaleType="center" android:src="@drawable/rgb" /> </RelativeLayout> </LinearLayout>

ColorPickerView颜色选取圆盘

package com.myview; import android.annotation.SuppressLint; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.PointF; import android.graphics.drawable.BitmapDrawable; import android.util.AttributeSet; import android.view.MotionEvent; import android.widget.ImageView; public class ColorPickerView extends ImageView { Context context; private Bitmap iconBitMap; float iconRadius;// 吸管圆的半径 float iconCenterX; float iconCenterY; PointF iconPoint;// 点击位置坐标 public ColorPickerView(Context context) { this(context, null); } public ColorPickerView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); this.context = context; init(); } public ColorPickerView(Context context, AttributeSet attrs) { this(context, attrs, 0); init(); } Paint mBitmapPaint; Bitmap imageBitmap; float viewRadius;// 整个view半径 float radius;// 图片半径 /** * 初始化画笔 */ private void init() { iconBitMap = BitmapFactory.decodeResource(context.getResources(), R.drawable.pickup);// 吸管的图片 iconRadius = iconBitMap.getWidth() / 2;// 吸管的图片一半 mBitmapPaint = new Paint(); iconPoint = new PointF(); imageBitmap = ((BitmapDrawable) getDrawable()).getBitmap(); radius = imageBitmap.getHeight() / 2;// 图片半径 // // 初始化 iconPoint.x = radius; iconPoint.y = radius; } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { // TODO Auto-generated method stub super.onMeasure(widthMeasureSpec, heightMeasureSpec); } Canvas canvas; @Override protected void onDraw(Canvas canvas) { // TODO Auto-generated method stub super.onDraw(canvas); this.canvas = canvas; viewRadius = this.getWidth() / 2;// 整个view半径 canvas.drawBitmap(iconBitMap, iconPoint.x - iconRadius, iconPoint.y - iconRadius, mBitmapPaint); } @SuppressLint("ClickableViewAccessibility") @Override public boolean onTouchEvent(MotionEvent event) { float x = event.getX(); float y = event.getY(); int pixel; int r; int g; int b; switch (event.getAction()) { case MotionEvent.ACTION_MOVE: proofLeft(x, y); pixel = getImagePixel(iconPoint.x, iconPoint.y); r = Color.red(pixel); g = Color.green(pixel); b = Color.blue(pixel); if (mChangedListener != null) { mChangedListener.onMoveColor(r, g, b); } if (isMove) { isMove = !isMove; invalidate(); } break; case MotionEvent.ACTION_UP: pixel = getImagePixel(iconPoint.x, iconPoint.y); r = Color.red(pixel); g = Color.green(pixel); b = Color.blue(pixel); if (mChangedListener != null) { mChangedListener.onColorChanged(r, g, b); } break; default: break; } return true; } public int getImagePixel(float x, float y) { Bitmap bitmap = imageBitmap; // 为了防止越界 int intX = (int) x; int intY = (int) y; if (intX < 0) intX = 0; if (intY < 0) intY = 0; if (intX >= bitmap.getWidth()) { intX = bitmap.getWidth() - 1; } if (intY >= bitmap.getHeight()) { intY = bitmap.getHeight() - 1; } int pixel = bitmap.getPixel(intX, intY); return pixel; } /** * R = sqrt(x * x + y * y) * point.x = x * r / R + r * point.y = y * r / R + r */ private void proofLeft(float x, float y) { float h = x - viewRadius; // 取xy点和圆点 的三角形宽 float w = y - viewRadius;// 取xy点和圆点 的三角形长 float h2 = h * h; float w2 = w * w; float distance = (float) Math.sqrt((h2 + w2)); // 勾股定理求 斜边距离 if (distance > radius) { // 如果斜边距离大于半径，则取点和圆最近的一个点为x,y float maxX = x - viewRadius; float maxY = y - viewRadius; x = ((radius * maxX) / distance) + viewRadius; // 通过三角形一边平行原理求出x,y y = ((radius * maxY) / distance) + viewRadius; } iconPoint.x = x; iconPoint.y = y; isMove = true; } boolean isMove; public void setOnColorChangedListenner(OnColorChangedListener l) { this.mChangedListener = l; } private OnColorChangedListener mChangedListener; // 内部接口 回调颜色 rgb值 public interface OnColorChangedListener { // 手指抬起，确定颜色回调 void onColorChanged(int r, int g, int b); // 移动时颜色回调 void onMoveColor(int r, int g, int b); } }

MyViewActivity主界面

package com.myview; import com.myview.ColorPickerView.OnColorChangedListener; import android.app.Activity; import android.os.Bundle; import android.widget.TextView; import android.widget.Toast; public class MyViewActivity extends Activity { TextView tv_rgb; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); tv_rgb=(TextView)this.findViewById(R.id.tv_rgb); ColorPickerView cpv=(ColorPickerView)this.findViewById(R.id.cpv); cpv.setOnColorChangedListenner(new OnColorChangedListener() { /** * 手指抬起，选定颜色时 */ @Override public void onColorChanged(int r, int g, int b) { if(r==0 && g==0 && b==0){ return; } Toast.makeText(MyViewActivity.this, "选取 RGB:"+r+","+g+","+b, Toast.LENGTH_SHORT).show(); } /** * 颜色移动的时候 */ @Override public void onMoveColor(int r, int g, int b) { if(r==0 && g==0 && b==0){ return; } tv_rgb.setText("RGB:"+r+","+g+","+b); } }); } }

详细项目代码：

源码下载：Android实现颜色选取圆盘

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。