DrawPath在android自定義視圖

Question

我有一個封閉的路徑，我想用一種顏色（白色）填充它，並在其周圍放置另一種顏色（紅色）的邊緣。我想到了一個自定義視圖類，可以讓我達到這個目的：

public class StrokeFill extends View{ 
private Path shapePath; 
private Paint strokePaint; 
private Paint fillPaint; 


public StrokeFill(Context context, Path path) { 
    super(context); 
    shapePath = path; 
    fillPaint.setColor(android.graphics.Color.WHITE); 
    fillPaint.setStyle(Paint.Style.FILL); 
    fillPaint.setStrokeWidth(0); 
    strokePaint.setColor(android.graphics.Color.RED); 
    strokePaint.setStyle(Paint.Style.STROKE); 
    strokePaint.setStrokeWidth(3); 
    // TODO Auto-generated constructor stub 
} 

protected void onDraw(Canvas canvas) { 
    // TODO Auto-generated method stub 
    //canvas.drawColor(Color.BLACK); 
    super.onDraw(canvas); 
    canvas.drawPath(shapePath, fillPaint); 
    canvas.drawPath(shapePath, strokePaint); 
} 
} 

在我的主要活動，我只是做這個（沒有XML配置文件）：

setContentView(new StrokeFill(this, testpath)); 

testpath是我定義的路徑在活動中。這是有效的，因爲我可以在使用它定義PathShape時繪製它。 但在這種情況下，Eclipse給我錯誤java.lang.NullPointerException。我試圖在XML佈局中定義自定義視圖，但這也不起作用。在android中使用形狀一直非常令人沮喪，所以如果有人能夠提供幫助，這將非常棒！

Answer 1

問題與您初始化看看這個

public class StrokeFill extends View{ 
    private Path shapePath; 
    private Paint strokePaint; 
    private Paint fillPaint; 

    public StrokeFill(Context context, Path path) { 
     super(context); 
     shapePath = new Path();   
     shapePath = path; 
     fillPaint = new Paint(); 
     fillPaint.setColor(android.graphics.Color.WHITE); 
     fillPaint.setStyle(Paint.Style.FILL); 
     fillPaint.setStrokeWidth(0); 
     strokePaint = new Paint(); 
     strokePaint.setColor(android.graphics.Color.RED); 
     strokePaint.setStyle(Paint.Style.STROKE); 
     strokePaint.setStrokeWidth(3); 
     // TODO Auto-generated constructor stub 
    } 

    protected void onDraw(Canvas canvas) { 
     // TODO Auto-generated method stub 
     //canvas.drawColor(Color.BLACK); 
     super.onDraw(canvas); 
     canvas.drawPath(shapePath, fillPaint); 
     canvas.drawPath(shapePath, strokePaint); 
    } 
} 

Answer 2

strokePaint永遠不會在您的代碼中初始化......是您的nullPointer？

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