Android example source code file (PathEffects.java)

This example Android source code file (PathEffects.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, composepatheffect, content, cornerpatheffect, dashpatheffect, graphicsactivity, keyevent, os, override, paint, path, pathdashpatheffect, patheffect, patheffects, rectf, sampleview, ui, view

The PathEffects.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.KeyEvent;
import android.view.View;

public class PathEffects extends GraphicsActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(new SampleView(this));
    }
    
    private static class SampleView extends View {
        private Paint mPaint;
        private Path mPath;
        private PathEffect[] mEffects;
        private int[] mColors;
        private float mPhase;

        private static PathEffect makeDash(float phase) {
            return new DashPathEffect(new float[] { 15, 5, 8, 5 }, phase);
        }
        
        private static void makeEffects(PathEffect[] e, float phase) {
            e[0] = null;     // no effect
            e[1] = new CornerPathEffect(10);
            e[2] = new DashPathEffect(new float[] {10, 5, 5, 5}, phase);
            e[3] = new PathDashPathEffect(makePathDash(), 12, phase,
                                          PathDashPathEffect.Style.ROTATE);
            e[4] = new ComposePathEffect(e[2], e[1]);
            e[5] = new ComposePathEffect(e[3], e[1]);
        }
        
        public SampleView(Context context) {
            super(context);
            setFocusable(true);
            setFocusableInTouchMode(true);

            mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
            mPaint.setStyle(Paint.Style.STROKE);
            mPaint.setStrokeWidth(6);
            
            mPath = makeFollowPath();
            
            mEffects = new PathEffect[6];
            
            mColors = new int[] { Color.BLACK, Color.RED, Color.BLUE,
                                  Color.GREEN, Color.MAGENTA, Color.BLACK
                                };
        }
        
        @Override protected void onDraw(Canvas canvas) {
            canvas.drawColor(Color.WHITE);
            
            RectF bounds = new RectF();
            mPath.computeBounds(bounds, false);
            canvas.translate(10 - bounds.left, 10 - bounds.top);
            
            makeEffects(mEffects, mPhase);
            mPhase += 1;
            invalidate();

            for (int i = 0; i < mEffects.length; i++) {
                mPaint.setPathEffect(mEffects[i]);
                mPaint.setColor(mColors[i]);
                canvas.drawPath(mPath, mPaint);
                canvas.translate(0, 28);
            }
        }
        
        @Override public boolean onKeyDown(int keyCode, KeyEvent event) {
            switch (keyCode) {
                case KeyEvent.KEYCODE_DPAD_CENTER:
                    mPath = makeFollowPath();
                    return true;
            }
            return super.onKeyDown(keyCode, event);
        }

        private static Path makeFollowPath() {
            Path p = new Path();
            p.moveTo(0, 0);
            for (int i = 1; i <= 15; i++) {
                p.lineTo(i*20, (float)Math.random() * 35);
            }
            return p;
        }
        
        private static Path makePathDash() {
            Path p = new Path();
            p.moveTo(4, 0);
            p.lineTo(0, -4);
            p.lineTo(8, -4);
            p.lineTo(12, 0);
            p.lineTo(8, 4);
            p.lineTo(0, 4);
            return p;
        }
    }
}