android中获取 bitmap 像素的颜色 之吸管取色功能

本功能是参考android API colorPickerView修改，实现类似与PS中吸管取色功能。也就是可以对图片的任意位置取该位置的RGB。本demo中，完成了色盘取色功能。当点击色盘的某个位置，松手时，显示当前的颜色。由于是demo，显示的颜色用button的文字颜色的相应改变达到效果。把色盘图片更换为其他资源，则对你换的资源取色。具体要按需求改动。色盘取色可以用于绘图时的颜色选择，不用弹出对话框选择有限的几种颜色。总得来说还是吸管功能。

主要代码如下：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.mrlin.mycolordisk"
    android:versionCode="1"
    android:versionName="1.0" >

<uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />

<application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.mrlin.mycolordisk.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>
 来自CODE的代码片
AndroidManifest.xml

package com.mrlin.mycolordisk;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PointF;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

public class ColorPickerView extends View   {

private Context mContext;
private Paint mRightPaint;            //画笔
private int mHeight;                  //view高
private int mWidth;                   //view宽
private int[] mRightColors;
private int LEFT_WIDTH;
private Bitmap mLeftBitmap;
private Bitmap mLeftBitmap2;
private Paint mBitmapPaint;
private PointF mLeftSelectPoint; 
private OnColorChangedListener mChangedListener;
private boolean mLeftMove = false;
private float mLeftBitmapRadius;
private Bitmap mGradualChangeBitmap;
private Bitmap bitmapTemp;
private int mCallBackColor = Integer.MAX_VALUE;
int newWidgth;
int newHeigh;
    public static String hexColor="";
public static int ColorText=0;

public ColorPickerView(Context context) {
this(context, null);
}

public ColorPickerView(Context context, AttributeSet attrs) {
super(context, attrs);
mContext = context;
init();
}

public void setOnColorChangedListenner(OnColorChangedListener listener) {

mChangedListener = listener;
mChangedListener.onColorChanged(ColorText);
}

//初始化资源与画笔
private void init() {
bitmapTemp = BitmapFactory.decodeResource(getResources(), R.drawable.piccolor); 
mRightPaint = new Paint(); 
mRightPaint.setStyle(Paint.Style.FILL);
mRightPaint.setStrokeWidth(1);
mRightColors = new int[3];
mRightColors[0] = Color.WHITE;
mRightColors[2] = Color.BLACK;
mBitmapPaint = new Paint();

mLeftBitmap = BitmapFactory.decodeResource(mContext.getResources(), R.drawable.reading__color_view__button);
mLeftBitmap2 = BitmapFactory.decodeResource(mContext.getResources(), R.drawable.reading__color_view__button_press);
mLeftBitmapRadius = mLeftBitmap.getWidth() / 2;
mLeftSelectPoint = new PointF(0, 0); 
newWidgth=BitmapFactory.decodeResource(getResources(), R.drawable.piccolor).getWidth();
newHeigh=BitmapFactory.decodeResource(getResources(), R.drawable.piccolor).getHeight(); 
}

//important patient please!!!
@Override
protected void onDraw(Canvas canvas) { 
canvas.drawBitmap(getGradual() , null , new 
Rect(0, 0, LEFT_WIDTH , mHeight ), mBitmapPaint);
// 右边

// 两个图标
if (mLeftMove) {
canvas.drawBitmap(mLeftBitmap, mLeftSelectPoint.x - mLeftBitmapRadius,
mLeftSelectPoint.y - mLeftBitmapRadius, mBitmapPaint);
} else {
try {

canvas.drawBitmap(mLeftBitmap2, mLeftSelectPoint.x - mLeftBitmapRadius, 
mLeftSelectPoint.y - mLeftBitmapRadius, mBitmapPaint);
} catch (Exception e) {
// TODO: handle exception
}
}
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int widthMode = MeasureSpec.getMode(widthMeasureSpec);
int heightMode = MeasureSpec.getMode(heightMeasureSpec);
int width = MeasureSpec.getSize(widthMeasureSpec);
int height = MeasureSpec.getSize(heightMeasureSpec);
if (widthMode == MeasureSpec.EXACTLY) {
mWidth = width;
} else {
mWidth = newHeigh;
}
if (heightMode == MeasureSpec.EXACTLY) {
mHeight = height;
} else {
mHeight = newHeigh;
}
LEFT_WIDTH = mWidth;
setMeasuredDimension(mWidth, mHeight);
}

@Override
public boolean onTouchEvent(MotionEvent event) {
float x = event.getX();
float y = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
case MotionEvent.ACTION_MOVE:
mLeftMove = true;
proofLeft(x, y);
   invalidate();
break;
case MotionEvent.ACTION_UP:
//取色
ColorText=getLeftColor(x, y); 
mLeftMove = false;
invalidate();
//松手后，此变量置真，更新button字体颜色
MainActivity.flagOfColorChange=true;
}
return true;
}

@Override
protected void onDetachedFromWindow() {
if (mGradualChangeBitmap != null && mGradualChangeBitmap.isRecycled() == false) {
mGradualChangeBitmap.recycle();
}
if (mLeftBitmap != null && mLeftBitmap.isRecycled() == false) {
mLeftBitmap.recycle();
}
if (mLeftBitmap2 != null && mLeftBitmap2.isRecycled() == false) {
mLeftBitmap2.recycle();
}
super.onDetachedFromWindow();
}

private Bitmap getGradual() {
if (mGradualChangeBitmap == null) {
Paint leftPaint = new Paint();
leftPaint.setStrokeWidth(1); 
mGradualChangeBitmap = Bitmap.createBitmap(LEFT_WIDTH, mHeight, Config.RGB_565);
mGradualChangeBitmap.eraseColor(Color.WHITE);
Canvas canvas = new Canvas(mGradualChangeBitmap); 
    canvas.drawBitmap( bitmapTemp, null , new Rect(0, 0, LEFT_WIDTH , mHeight ), mBitmapPaint);
}
return mGradualChangeBitmap;
}
// 校正xy
private void proofLeft(float x, float y) {
if (x < 0) {
mLeftSelectPoint.x = 0;
} else if (x > (LEFT_WIDTH)) {
mLeftSelectPoint.x = LEFT_WIDTH;
} else {
mLeftSelectPoint.x = x;
}
if (y < 0) {
mLeftSelectPoint.y = 0;
} else if (y > (mHeight - 0)) {
mLeftSelectPoint.y = mHeight - 0;
} else {
mLeftSelectPoint.y = y;
}
}

private int getLeftColor(float x, float y) {
Bitmap temp = getGradual();
// 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 >= temp.getWidth()) {
intX = temp.getWidth() - 1;
}
if (intY >= temp.getHeight()) {
intY = temp.getHeight() - 1;
}

System.out.println("leftColor"+temp.getPixel(intX, intY));
        return temp.getPixel(intX, intY);
}

// ### 内部类 ###
public interface OnColorChangedListener {
void onColorChanged(int color);
}

}
 来自CODE的代码片
ColorPickerView.java

package com.mrlin.mycolordisk;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.Menu;
import android.widget.Button;

import com.mrlin.mycolordisk.ColorPickerView.OnColorChangedListener;

public class MainActivity extends Activity {

private ColorPickerView colorDisk=null;
private Button btnColor=null;
public static boolean flagOfColorChange=false;
private final static int COLOR_CHANGE=1;
Handler mColorhandler=new Handler()
{
public void handleMessage(Message msg)
{
switch(msg.what)
{
case COLOR_CHANGE:
btnColor.setTextColor(ColorPickerView.ColorText);
break;

default:
break;
}
};
};

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);  
btnColor=(Button)findViewById(R.id.btnColor);

//用线程监听 是否颜色已经改变
new Thread(new Runnable() {

@Override
public void run() {
// TODO Auto-generated method stub
while(true)
{
//当色盘颜色改变时，也就是松手时，把flagOfColorChange置为true
//然后handler 发送消息，button改变字体

//此变量为全局变量，破坏了封装性。但是实现了功能，有更好的方式可以留言
if(flagOfColorChange) 
{

System.out.println("color change!!!");
flagOfColorChange=false;
mColorhandler.sendEmptyMessage(COLOR_CHANGE);
}
}

}
}).start();
}

@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;
}

}
 来自CODE的代码片
MainActivity.java

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    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=".MainActivity" >

<com.mrlin.mycolordisk.ColorPickerView
         android:id="@+id/colorDisk"
         android:layout_width="fill_parent"
         android:layout_height="300dp"
         android:layout_alignLeft="@+id/btnColor"
         android:layout_alignRight="@+id/btnColor" />

<Button
         android:id="@+id/btnColor"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_alignParentLeft="true"
         android:layout_alignParentRight="true"
         android:layout_below="@+id/colorDisk"
         android:layout_marginTop="37dp"
         android:text="color" />
     
</RelativeLayout>
 来自CODE的代码片
activity_main.xml

运行效果如下：