Question

是否有一种简单的方法可以在画布上绘制矩形并将其显示在像TextView这样的活动中？

我试图像这样绘制我的矩形：

Paint paint = new Paint();
paint.setStyle(Paint.Style.FILL);
paint.setColor(Color.MAGENTA); 
Bitmap b = Bitmap.createBitmap(100, 100, Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(b);

Rect locationrect = new Rect(10, 10, 200, 100);
c.drawRect(locationrect, paint);

View locationpic = (View)findViewById(R.id.locationview);
locationpic.draw(c);

在我的xml中：

<View
    android:id="@+id/locationview"
    android:layout_width="520dp"
    android:layout_height="489dp"
    android:layout_marginLeft="40dp"
    android:layout_marginTop="220dp" />

这显然不起作用（它没有崩溃，但没有显示矩形）..任何帮助将不胜感激！谢谢！

Answer 1

创建一个Java文件并写下：

package com.samplecanvas;

import java.util.ArrayList;

import android.app.Activity; import android.content.Context; import android.graphics.Bitmap; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.Path; import android.graphics.Rect; import android.graphics.RectF; import android.os.Bundle; import android.view.MotionEvent; import android.view.SurfaceHolder; import android.view.SurfaceView; import android.view.View; import android.view.View.OnTouchListener; import android.view.ViewGroup.LayoutParams; import android.view.Window; import android.view.WindowManager; import android.widget.FrameLayout;

import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.view.View;

      public class SampleCanvasActivity extends View {
         vPaint paint = new Paint();

          public SampleCanvasActivity(Context context) {
              super(context);
           }

@Override
public void onDraw(Canvas canvas) {
    paint.setColor(Color.BLACK);
    paint.setStrokeWidth(3);
    canvas.drawRect(130, 130, 180, 180, paint);
    paint.setStrokeWidth(0);
    paint.setColor(Color.CYAN);
    canvas.drawRect(133, 160, 177, 177, paint );
    paint.setColor(Color.YELLOW);
    canvas.drawRect(133, 133, 177, 160, paint );

}

}

在ur xml中使用此文件

喜欢这个。

  <com.samplecanvas.SampleCanvasActivity
android:id="@+id/widthView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="30dp"
android:layout_marginTop="150dp"
 />

通过将画布视为视图来绘制矩形

1 个答案: