安卓：試圖從顏色代碼位圖。它返回null

Question

我試圖創建顏色代碼colors.xml

定義爲繪製位圖每當我試圖從它這條線創建位圖拋出一個空指針異常。

如何從特定顏色代碼創建位圖。無論哪種用作R.color或R.drawable

Answer 1

程序：

Bitmap result = Bitmap.createBitmap(48,48, Config.ARGB_8888);  
      Canvas canvas = new Canvas(result);  
    // ..... 
    canvas.drawBitmap(result, rect, rect, paint); 

XML：

RES /抽拉：

<?xml version="1.0" encoding="utf-8"?> 
    <bitmap xmlns:android="http://schemas.android.com/apk/res/android" 
     android:src="@drawable/bg_toolbar" 
     android:tileMode="repeat" /> 

Answer 2

//用法：genBitMapforAnim（ 「5」，48）

protected Bitmap genBitMapforAnim(String itemCode, int size) { 
     String text = itemCode.length() >= 5 ? itemCode.substring(0, 5) : itemCode; 
     Bitmap result = Bitmap.createBitmap(size*2,size*2, Config.ARGB_8888); 
     Canvas canvas = new Canvas(result); 
     canvas.drawARGB(0, 0xff, 0, 0); 
     Paint paint = new Paint(); 
     paint.setAntiAlias(true); 
     paint.setFilterBitmap(true); 
     paint.setColor(Color.RED); //use your background color 
     paint.setAlpha(200); 
     canvas.drawCircle(size/2, size/2, size/2, paint); 
     paint.setAlpha(255); 
     paint.setTextSize(9); 
     paint.setColor(Color.WHITE); //use your text color 
     float textWidth = paint.measureText(text); 
     FontMetrics fm = paint.getFontMetrics();  
     float textHeight = (float)(fm.descent + fm.ascent) 

     canvas.drawText(text, (size-textWidth) /2.0f,(size-textHeight)/2.0f, paint); 


     final Rect rect = new Rect(0, 0,size, size); 
     paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN)); 
     canvas.drawBitmap(result, rect, rect, paint); 
     return result; 
    } 

Answer 3

protected Bitmap genBitMapforAnim(String itemCode, int size) { 
     String text = itemCode.length() >= 5 ? itemCode.substring(0, 5) : itemCode; 
     Bitmap result = Bitmap.createBitmap(size*2,size*2, Config.ARGB_8888); 
     Canvas canvas = new Canvas(result); 
     canvas.drawARGB(0, 0xff, 0, 0); 
     Paint paint = new Paint(); 
     paint.setAntiAlias(true); 
     paint.setFilterBitmap(true); 
     paint.setColor(context.getResources().getColor(R.color.id)); //use your background color 
     paint.setAlpha(200); 
     canvas.drawCircle(size/2, size/2, size/2, paint); 
     paint.setAlpha(255); 
     paint.setTextSize(9); 
     paint.setColor(Color.WHITE); //use your text color 
     float textWidth = paint.measureText(text); 
     FontMetrics fm = paint.getFontMetrics();  
     float textHeight = (float)(fm.descent + fm.ascent) 

     canvas.drawText(text, (size-textWidth) /2.0f,(size-textHeight)/2.0f, paint); 


     final Rect rect = new Rect(0, 0,size, size); 
     paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN)); 
     canvas.drawBitmap(result, rect, rect, paint); 
     return result; 
    }