Android example source code file (DrawPoints.java)

This example Android source code file (DrawPoints.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

android, app, content, drawpoints, graphicsactivity, os, override, paint, sampleview, segs, size, ui, view, x, y

The DrawPoints.java Android example source code

/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.android.apis.graphics;

import android.app.Activity;
import android.content.Context;
import android.graphics.*;
import android.os.Bundle;
import android.view.View;

public class DrawPoints extends GraphicsActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(new SampleView(this));
    }
    
    private static class SampleView extends View {
        private Paint   mPaint = new Paint();
        private float[] mPts;

        private static final float SIZE = 300;
        private static final int SEGS = 32;
        private static final int X = 0;
        private static final int Y = 1;
        
        private void buildPoints() {
            final int ptCount = (SEGS + 1) * 2;
            mPts = new float[ptCount * 2];
            
            float value = 0;
            final float delta = SIZE / SEGS;
            for (int i = 0; i <= SEGS; i++) {
                mPts[i*4 + X] = SIZE - value;
                mPts[i*4 + Y] = 0;
                mPts[i*4 + X + 2] = 0;
                mPts[i*4 + Y + 2] = value;
                value += delta;
            }
        }
    
        public SampleView(Context context) {
            super(context);
            
            buildPoints();
        }
        
        @Override protected void onDraw(Canvas canvas) {
            Paint paint = mPaint;
            
            canvas.translate(10, 10);

            canvas.drawColor(Color.WHITE);

            paint.setColor(Color.RED);
            paint.setStrokeWidth(0);
            canvas.drawLines(mPts, paint);
            
            paint.setColor(Color.BLUE);
            paint.setStrokeWidth(3);
            canvas.drawPoints(mPts, paint);
        }
    }
}