这期内容当中小编将会给大家带来有关怎么在Android中通过自定义控件实现颜色选择器，文章内容丰富且以专业的角度为大家分析和叙述，阅读完这篇文章希望大家可以有所收获。
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activity_mian.xml文件：
MainActivity.java文件
package zxz.colorpickerdemo;
import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.LinearLayout;
import android.widget.TextView;
import zxz.colorpickerdemo.view.ColorPickerView;
public class MainActivity extends AppCompatActivity {
private LinearLayout ll;
private TextView tv;
private ColorPickerView colorPickerView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ll = (LinearLayout) findViewById(R.id.ll_color);
tv = (TextView) findViewById(R.id.tv_info);
colorPickerView = new ColorPickerView(this);
ll.addView(colorPickerView);
colorPickerView.setOnColorBackListener(new ColorPickerView.OnColorBackListener() {
@Override
public void onColorBack(int a, int r, int g, int b) {
tv.setText("R：" + r + "\nG：" + g + "\nB：" + b + "\n" + colorPickerView.getStrColor());
tv.setTextColor(Color.argb(a, r, g, b));
}
});
}
}可以发现，这里自定义控件并没有直接在布局文件使用，原因是因为需要用户根据不同的需求通过自定义控件的构造函数传递给控件，所以通过ViewGroup.add()将ColorPickerView添加进去！
ColorPickerView colorPickerView = new ColorPickerView(context);
ll.addView(colorPickerView);
-核心部分
就是ColorPickerView的实现代码
package zxz.colorpickerdemo.view;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.LinearGradient;
import android.graphics.Paint;
import android.graphics.RectF;
import android.graphics.Shader;
import android.graphics.SweepGradient;
import android.view.MotionEvent;
import android.view.View;
public class ColorPickerView extends View {
private static final float PI = (float) Math.PI;
private Paint paintCirclePhantom;
private Paint paintCircle;
private Paint paintCenterShadow;
private Paint paintCenter;
private Paint paintGrayShadow;
private Paint paintGray;
private Paint paintLightShadow;
private Paint paintLight;
private double Zoom;
private int[] arrColorGray;
private final int[] arrColorCircle = new int[]{0xFFFF0000, 0xFFFF00FF,
0xFF0000FF, 0xFF00FFFF, 0xFF00FF00, 0xFFFFFF00, 0xFFFF0000};
private boolean mRedrawHSV;
private boolean IsPressCenter;
private boolean IsMoveCenter;
private int CenterX = 100;
private int CenterY = 100;
private int CenterRadius = 30;
private String strColor = "";
private OnColorBackListener l;
public ColorPickerView(Context context) {
super(context);
float density = getContext().getResources().getDisplayMetrics().density;
double Zoom = (double) (density / 2.0 + 0.5);
int color = Color.parseColor("#FFFFFF");
init(color, Zoom);
}
public ColorPickerView(Context context, int color, double Zoom) {
super(context);
init(color, Zoom);
}
private void init(int color, double Zoom) {
this.Zoom = Zoom;
CenterX = (int) (100 * Zoom);
CenterY = (int) (100 * Zoom);
CenterRadius = (int) (30 * Zoom);
paintCirclePhantom = new Paint(Paint.ANTI_ALIAS_FLAG);
paintCircle = new Paint(Paint.ANTI_ALIAS_FLAG);
paintCenterShadow = new Paint(Paint.ANTI_ALIAS_FLAG);
paintCenter = new Paint(Paint.ANTI_ALIAS_FLAG);
paintGrayShadow = new Paint(Paint.ANTI_ALIAS_FLAG);
paintGray = new Paint(Paint.ANTI_ALIAS_FLAG);
paintLightShadow = new Paint(Paint.ANTI_ALIAS_FLAG);
paintLight = new Paint(Paint.ANTI_ALIAS_FLAG);
paintCirclePhantom.setColor(0xFF000000);
paintCirclePhantom.setStyle(Paint.Style.STROKE);
paintCirclePhantom.setStrokeWidth((float) (32 * Zoom));
paintCircle.setShader(new SweepGradient(0, 0, arrColorCircle, null));
paintCircle.setStyle(Paint.Style.STROKE);
paintCircle.setStrokeWidth((float) (32 * Zoom));
paintCenterShadow.setColor(0xFF000000);
paintCenterShadow.setStrokeWidth((float) (5 * Zoom));
paintCenter.setColor(color);
paintCenter.setStrokeWidth((float) (5 * Zoom));
paintGrayShadow.setColor(0xFF000000);
paintGrayShadow.setStrokeWidth((float) (30 * Zoom));
arrColorGray = new int[]{0xFFFFFFFF, color, 0xFF000000};
paintGray.setStrokeWidth((float) (30 * Zoom));
paintLightShadow.setColor(0xFF000000);
paintLightShadow.setStrokeWidth((float) (60 * Zoom));
paintLight.setStrokeWidth((float) (60 * Zoom));
mRedrawHSV = true;
}
@Override
protected void onDraw(Canvas canvas) {
canvas.translate(CenterX, CenterY);
float r = CenterX - paintCircle.getStrokeWidth() * 0.5f;
int color = paintCenter.getColor();
strColor = "#" + Integer.toHexString(color).substring(2).toUpperCase();
if (mRedrawHSV) {
arrColorGray[1] = color;
paintGray.setShader(new LinearGradient(CenterX, -CenterY, CenterX,
(float) (100 * Zoom), arrColorGray, null,
Shader.TileMode.CLAMP));
}
canvas.drawOval(new RectF(-r + 3, -r + 3, r + 3, r + 3),
paintCirclePhantom);
canvas.drawOval(new RectF(-r, -r, r, r), paintCircle);
canvas.drawCircle(3, 3, CenterRadius, paintCenterShadow);
canvas.drawCircle(0, 0, CenterRadius, paintCenter);
canvas.drawRect(new RectF(CenterX + (float) (18 * Zoom), -CenterY + 3,
CenterX + (float) (48 * Zoom), (float) (103 * Zoom)),
paintGrayShadow);
canvas.drawRect(new RectF(CenterX + (float) (15 * Zoom), -CenterY,
CenterX + (float) (45 * Zoom), (float) (100 * Zoom)), paintGray);
if (IsPressCenter) {
paintCenter.setStyle(Paint.Style.STROKE);
if (IsMoveCenter)
paintCenter.setAlpha(0xFF);
else
paintCenter.setAlpha(0x66);
canvas.drawCircle(0, 0,
CenterRadius + paintCenter.getStrokeWidth(), paintCenter);
paintCenter.setStyle(Paint.Style.FILL);
paintCenter.setColor(color);
}
mRedrawHSV = true;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
setMeasuredDimension(CenterX * 2 + 50, CenterY * 2 + 23);
}
private int ave(int s, int d, float p) {
return s + java.lang.Math.round(p * (d - s));
}
private int interpColor(int colors[], float unit) {
if (unit <= 0) {
return colors[0];
}
if (unit >= 1) {
return colors[colors.length - 1];
}
float p = unit * (colors.length - 1);
int i = (int) p;
p -= i;
int c0 = colors[i];
int c1 = colors[i + 1];
int a = ave(Color.alpha(c0), Color.alpha(c1), p);
int r = ave(Color.red(c0), Color.red(c1), p);
int g = ave(Color.green(c0), Color.green(c1), p);
int b = ave(Color.blue(c0), Color.blue(c1), p);
if (l != null) {
l.onColorBack(a, r, g, b);
}
return Color.argb(a, r, g, b);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
float x = event.getX() - CenterX;
float y = event.getY() - CenterY;
boolean inCenter = java.lang.Math.sqrt(x * x + y * y) <= CenterRadius;
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN: {
IsPressCenter = inCenter;
if (inCenter) {
IsMoveCenter = true;
invalidate();
break;
}
}
case MotionEvent.ACTION_MOVE: {
if (IsPressCenter) {
if (IsMoveCenter != inCenter) {
IsMoveCenter = inCenter;
invalidate();
}
} else if ((x >= -CenterX && x <= CenterX)
&& (y >= -CenterY && y <= CenterY)) {
float angle = (float) java.lang.Math.atan2(y, x);
float unit = angle / (2 * PI);
if (unit < 0)
unit += 1;
paintCenter.setColor(interpColor(arrColorCircle, unit));
invalidate();
} else {
int a, r, g, b, c0, c1;
float p;
if (y < 0) {
c0 = arrColorGray[0];
c1 = arrColorGray[1];
p = (y + 100) / 100;
} else {
c0 = arrColorGray[1];
c1 = arrColorGray[2];
p = y / 100;
}
a = ave(Color.alpha(c0), Color.alpha(c1), p);
r = ave(Color.red(c0), Color.red(c1), p);
g = ave(Color.green(c0), Color.green(c1), p);
b = ave(Color.blue(c0), Color.blue(c1), p);
paintCenter.setColor(Color.argb(a, r, g, b));
mRedrawHSV = false;
if (l != null) {
l.onColorBack(a, r, g, b);
}
invalidate();
}
break;
}
case MotionEvent.ACTION_UP: {
if (IsPressCenter) {
IsPressCenter = false;
invalidate();
}
break;
}
}
return true;
}
public Paint getpaintCirclePhantom() {
return paintCirclePhantom;
}
public void setpaintCirclePhantom(Paint paintCirclePhantom) {
this.paintCirclePhantom = paintCirclePhantom;
}
public Paint getPaintCircle() {
return paintCircle;
}
public void setPaintCircle(Paint paintCircle) {
this.paintCircle = paintCircle;
}
public Paint getPaintCenterShadow() {
return paintCenterShadow;
}
public void setPaintCenterShadow(Paint paintCenterShadow) {
this.paintCenterShadow = paintCenterShadow;
}
public Paint getPaintCenter() {
return paintCenter;
}
public void setPaintCenter(Paint paintCenter) {
this.paintCenter = paintCenter;
}
public Paint getPaintGrayShadow() {
return paintGrayShadow;
}
public void setPaintGrayShadow(Paint paintGrayShadow) {
this.paintGrayShadow = paintGrayShadow;
}
public Paint getPaintGray() {
return paintGray;
}
public void setPaintGray(Paint paintGray) {
this.paintGray = paintGray;
}
public int[] getArrColorGray() {
return arrColorGray;
}
public void setArrColorGray(int[] arrColorGray) {
this.arrColorGray = arrColorGray;
}
public boolean ismRedrawHSV() {
return mRedrawHSV;
}
public void setmRedrawHSV(boolean mRedrawHSV) {
this.mRedrawHSV = mRedrawHSV;
}
public boolean isIsPressCenter() {
return IsPressCenter;
}
public void setIsPressCenter(boolean isPressCenter) {
IsPressCenter = isPressCenter;
}
public boolean isIsMoveCenter() {
return IsMoveCenter;
}
public void setIsMoveCenter(boolean isMoveCenter) {
IsMoveCenter = isMoveCenter;
}
public int[] getArrColorCircle() {
return arrColorCircle;
}
public String getStrColor() {
return strColor;
}
public void setStrColor(String strColor) {
this.strColor = strColor;
}
public double getZoom() {
return Zoom;
}
public void setZoom(double zoom) {
Zoom = zoom;
}
public void setOnColorBackListener(OnColorBackListener l) {
this.l = l;
}
public interface OnColorBackListener {
public void onColorBack(int a, int r, int g, int b);
}
}注意：
1、ColorPickerView重写了两个构造方法，第一个ColorPickerView(context) 这个方法创建的取色器默认绘制的大小比为屏幕密度，默认的颜色为白色；第二个ColorPickerView(context, color, zoom) color为默认颜色，zoom为绘制大小比例。
2、调用colorPickerView的setOnColorBackListener方法监听颜色的变化，回调 a r g b 0~255的值。colorPickerView.getStrColor()获取rgb对应的十六进制值，比如#FF00FF
Android是什么
Android是一种基于Linux内核的自由及开放源代码的操作系统，主要使用于移动设备，如智能手机和平板电脑，由美国Google公司和开放手机联盟领导及开发。
上述就是小编为大家分享的怎么在Android中通过自定义控件实现颜色选择器了，如果刚好有类似的疑惑，不妨参照上述分析进行理解。如果想知道更多相关知识，欢迎关注创新互联行业资讯频道。
新闻标题：怎么在Android中通过自定义控件实现颜色选择器
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