如何在画布上绘制文字？

Question

我正在尝试为android开发一个简单的饼图类.现在,它可以获取标签和值的映射并绘制饼图.我还没有添加馅饼的图例,这是我需要将文本放在屏幕角落的小矩形附近的地方.任何帮助表示赞赏,因为我是Android开发人员的新手.

Answer 1

您将不得不使用Canvas类的drawText方法.

Paint paint = new Paint(); 
canvas.drawPaint(paint); 
paint.setColor(Color.BLACK); 
paint.setTextSize(16); 
canvas.drawText("My Text", x, y, paint); 

这是关于它的相关文档:

http://developer.android.com/reference/android/graphics/Canvas.html#drawText(java.lang.String,float,flove,android.graphics.Paint)

Answer 2

这里曾经有另一个答案被删除,因为它只是一个链接.原始链接在这里.代码基本相同,但我拿出了非文本绘图部分,并且还扩大了尺寸,以便在现代屏幕密度上更好地工作.

这只是展示了一些你可以用文字绘制做的事情.

这是更新的代码:

public class MainActivity extends AppCompatActivity {

    DemoView demoview;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        demoview = new DemoView(this);
        setContentView(demoview);
    }

    private class DemoView extends View {
        public DemoView(Context context){
            super(context);
        }

        @Override protected void onDraw(Canvas canvas) {
            super.onDraw(canvas);

            // custom drawing code here
            // remember: y increases from top to bottom
            // x increases from left to right
            int x = 0;
            int y = 0;
            Paint paint = new Paint();
            paint.setStyle(Paint.Style.FILL);

            canvas.save();
            canvas.translate(100, 200);

            // make the entire canvas white
            canvas.drawColor(Color.WHITE);

            // draw some text using STROKE style
            paint.setStyle(Paint.Style.STROKE);
            paint.setStrokeWidth(1);
            paint.setColor(Color.MAGENTA);
            paint.setTextSize(100);
            canvas.drawText("Style.STROKE", 0, 0, paint);

            canvas.translate(0, 200);

            // draw some text using FILL style
            paint.setStyle(Paint.Style.FILL);
            //turn antialiasing on
            paint.setAntiAlias(true);
            //paint.setTextSize(30);
            canvas.drawText("Style.FILL", 0, 0, paint);

            canvas.translate(0, 200);

            // draw some rotated text
            // get text width and height
            // set desired drawing location
            x = 75;
            y = 185;
            paint.setColor(Color.GRAY);
            //paint.setTextSize(25);
            String str2rotate = "Rotated!";

            // draw bounding rect before rotating text
            Rect rect = new Rect();
            paint.getTextBounds(str2rotate, 0, str2rotate.length(), rect);
            canvas.translate(x, y);
            paint.setStyle(Paint.Style.FILL);
            // draw unrotated text
            canvas.drawText("!Rotated", 0, 0, paint);
            paint.setStyle(Paint.Style.STROKE);
            canvas.drawRect(rect, paint);
            // undo the translate
            canvas.translate(-x, -y);

            // rotate the canvas on center of the text to draw
            canvas.rotate(-45, x + rect.exactCenterX(),
                    y + rect.exactCenterY());
            // draw the rotated text
            paint.setStyle(Paint.Style.FILL);
            canvas.drawText(str2rotate, x, y, paint);

            //undo the translation and rotation
            canvas.restore();
        }
    }
}

我想稍后尝试的其他东西是沿着路径绘制文本.

另请参阅此处更全面的答案,其中给出了以下图像.