Bitmap.getPixel总是返回黑 [英] Bitmap.getPixel always returning black

问题描述

我创建其中涉及越来越的屏幕部分的颜色的应用程序。
要做到这一点，我现在用的是Bitmap.getPixel方法来检索屏幕的指​​定像素，比我将其转换为RGB格式，使其更容易对我来说，code与后来的。问题是，不管是什么，当我使用与getPixel方法在屏幕上，它总是返回相同的RGB值，R：0 G：0 B：0，或黑色，即使有一个灰色按钮覆盖整个屏幕！这里是code

 包proof.of.concept;进口android.app.Activity;
进口android.graphics.Bitmap;
进口android.graphics.Color;
进口android.os.Bundle;
进口android.util.Log;
进口android.view.Display;
进口android.view.View;
导入android.widget *。
公共类ColorCheckerProofOfConcept延伸活动{
    私有静态最后弦乐TAG =ColorChckerProofOfConcept ::;
    / **当第一次创建活动调用。 * /
    @覆盖
    公共无效的onCreate（捆绑savedInstanceState）{
        super.onCreate（savedInstanceState）;
        的setContentView（R.layout.main）;
        最后Button按钮=（按钮）findViewById（R.id.button1）;     button.setOnClickListener（新View.OnClickListener（）{
         公共无效的onClick（视图v）{
             显示显示= getWindowManager（）getDefaultDisplay（）。
                INT宽度= display.getWidth（）;
                INT高度= display.getHeight（）;
                   Log.d（TAG，宽度和高度检索为：+宽+，+高）;
                位图B = Bitmap.createBitmap（宽度，高度，Bitmap.Config RGB_565）;
                串hexValue;                 INT测试;
              测试= b.getPixel（240，350）;             hexValue = Integer.toHexString（测试）;
             Log.d（TAG，在100像素，200成功地与retreived价值：！+测试）;
             Log.d（TAG，和一个十六进制值：+ hexValue）;
             INT蓝= Color.blue（试验）;
             INT红色= Color.red（试验）;
             INT绿色= Color.green（试验）;
//这是一个修改               Log.d（TAG！RGB颜色R：+红+G：+绿色+B：+蓝色）;
         }
     }）;
   }
}
 

解决方案

您从您的位图拉没有什么是您的屏幕上。您创建了一个黑色的位图屏幕的大小，但不是你的屏幕。您code适用于从位图拉。你们是不是要创建屏幕的位图？

I'm creating an app which involves getting the color of part of the screen. To do this I am using the Bitmap.getPixel method to retrieve a specified pixel of the screen, than I am converting it to RGB format to make it easier for me to code with later. The issue is no matter what is on the screen when i use the getPixel method, it always returns the same RGB values, R:0 G:0 B:0, or Black, even when there is a gray button covering up the entire screen! Here is the code

package proof.of.concept;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Color;
import android.os.Bundle;
import android.util.Log;
import android.view.Display;
import android.view.View;
import android.widget.*;
public class ColorCheckerProofOfConcept extends Activity {
    private static final String TAG = "ColorChckerProofOfConcept:: ";  
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        final Button button = (Button) findViewById(R.id.button1);

     button.setOnClickListener(new View.OnClickListener() {
         public void onClick(View v) {
             Display display = getWindowManager().getDefaultDisplay();
                int width = display.getWidth();
                int height = display.getHeight();
                   Log.d(TAG, "Width and Height Retrieved As: " + width + ", " + height);
                Bitmap b = Bitmap.createBitmap(width, height, Bitmap.Config. RGB_565);
                String hexValue;

                 int test;
              test = b.getPixel(240, 350);

             hexValue = Integer.toHexString(test);
             Log.d(TAG, "pixel at 100, 200 succesfully retreived! with value of: " + test);
             Log.d(TAG, "and an Hex value of: " + hexValue);
             int blue = Color.blue(test);
             int red = Color.red(test);
             int green = Color.green(test);
//this is a modification

               Log.d(TAG, "RGB COLOR! R:" + red + " G:" + green + " B:" + blue);
         }
     });
   }
}

解决方案

You are pulling from your Bitmap not what is on your screen. You created a black bitmap the size of your screen but not of your screen. Your code works for pulling from that bitmap. Are you trying to create a bitmap of your screen?

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