前言
Android 自定义 View 技能是成为高级工程师所必备的，笔者觉得自定义 View 没有什么捷径可走，唯有经常练习才能解决产品需求。笔者也好久没有写自定义 View 了，赶紧写个控件找点感觉回来。
本文实现的是一个 锁屏图案的自定义控件。效果图如下：
Github 地址：AndroidSample
LockView 介绍
自定义属性:
引用方式：
(1) 在布局文件中引入
<com.xing.androidsample.view.LockView android:id="@+id/lock_view" app:rowCount="4" app:normalColor="" app:moveColor="" app:errorColor="" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_margin="40dp" />
(2) 在代码中设置正确的图案，用于校验是否匹配成功，并在回调中获取结果
List<Integer> intList = new ArrayList<>(); intList.add(3); intList.add(7); intList.add(4); intList.add(2); lockView.setStandard(intList); lockView.setOnDrawCompleteListener(new LockView.OnDrawCompleteListener() { @Override public void onComplete(boolean isSuccess) { Toast.makeText(CustomViewActivity.this, isSuccess ? "success" : "fail", Toast.LENGTH_SHORT).show(); } }); 实现思路
- 以默认状态绘制 rowCount * rowCount 个圆，外圆颜色需要在内圆颜色上加上一定的透明度。
- 在 onTouchEvent() 方法中，判断当前触摸点与各个圆的圆心距离是否小于圆的半径，决定各个圆此时处于哪个状态（normal,move,error）,调用 invalidate() 重新绘制，更新颜色。
- 将手指滑动触摸过的圆的坐标添加到一个 ArrayList 中，使用 Path 连接该集合中选中的圆，即可绘制出划过的路径线。
实现步骤
自定义属性
在 res/values 目录下新建 attrs.xml 文件：
<?xml version="1.0" encoding="utf-8"?><resources> <declare-styleable name="LockView"> <attr name="normalColor" format="color|reference" /> <!--默认圆颜色--> <attr name="moveColor" format="color|reference" /> <!--手指触摸选中圆颜色--> <attr name="errorColor" format="color|reference" /> <!--手指抬起错误圆颜色--> <attr name="rowCount" format="integer" /> <!--每行每列圆的个数--> </declare-styleable></resources>
获取自定义属性
public LockView(Context context) { this(context, null); } public LockView(Context context, @Nullable AttributeSet attrs) { super(context, attrs); readAttrs(context, attrs); init(); } /** * 获取自定义属性 */ private void readAttrs(Context context, AttributeSet attrs) { TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.LockView); normalColor = typedArray.getColor(R.styleable.LockView_normalColor, DEFAULT_NORMAL_COLOR); moveColor = typedArray.getColor(R.styleable.LockView_moveColor, DEFAULT_MOVE_COLOR); errorColor = typedArray.getColor(R.styleable.LockView_errorColor, DEFAULT_ERROR_COLOR); rowCount = typedArray.getInteger(R.styleable.LockView_rowCount, DEFAULT_ROW_COUNT); typedArray.recycle(); } /** * 初始化 */ private void init() { stateSparseArray = new SparseIntArray(rowCount * rowCount); points = new PointF[rowCount * rowCount]; innerCirclePaint = new Paint(Paint.ANTI_ALIAS_FLAG); innerCirclePaint.setStyle(Paint.Style.FILL); outerCirclePaint = new Paint(Paint.ANTI_ALIAS_FLAG); outerCirclePaint.setStyle(Paint.Style.FILL); linePaint = new Paint(Paint.ANTI_ALIAS_FLAG); linePaint.setStyle(Paint.Style.STROKE); linePaint.setStrokeCap(Paint.Cap.ROUND); linePaint.setStrokeJoin(Paint.Join.ROUND); linePaint.setStrokeWidth(30); linePaint.setColor(moveColor); } 计算圆的半径
设定外圆半径和相邻两圆之间间距相同，内圆半径是外圆半径的一半，所以半径计算方式为：
radius = Math.min(w, h) / (2 * rowCount + rowCount - 1) * 1.0f;
设置各圆坐标
各圆坐标使用一维数组保存，计算方式为：
// 各个圆设置坐标点for (int i = 0; i < rowCount * rowCount; i++) { points[i] = new PointF(0, 0); points[i].set((i % rowCount * 3 + 1) * radius, (i / rowCount * 3 + 1) * radius);} 测量 View 宽高
根据测量模式设置控件的宽高，当布局文件中设置的是 wrap_content ,默认将控件宽高设置为 600dp
@Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); int width = getSize(widthMeasureSpec); int height = getSize(heightMeasureSpec); setMeasuredDimension(width, height); } private int getSize(int measureSpec) { int mode = MeasureSpec.getMode(measureSpec); int size = MeasureSpec.getSize(measureSpec); if (mode == MeasureSpec.EXACTLY) { return size; } else if (mode == MeasureSpec.AT_MOST) { return Math.min(size, dp2Px(600)); } return dp2Px(600); } onTouchEvent() 触摸事件
在手指滑动过程中，根据当前触摸点坐标是否落在圆的范围内，更新该圆的状态，在重新绘制时，绘制成新的颜色。手指抬起时，将存放状态的 list，选中圆的 list ，linePath 重置，并将结果回调出来。
private PointF touchPoint; @Override public boolean onTouchEvent(MotionEvent event) { switch (event.getAction()) { case MotionEvent.ACTION_DOWN: reset(); case MotionEvent.ACTION_MOVE: if (touchPoint == null) { touchPoint = new PointF(event.getX(), event.getY()); } else { touchPoint.set(event.getX(), event.getY()); } for (int i = 0; i < rowCount * rowCount; i++) { // 是否触摸在圆的范围内 if (getDistance(touchPoint, points[i]) < radius) { stateSparseArray.put(i, STATE_MOVE); if (!selectedList.contains(points[i])) { selectedList.add(points[i]); } break; } } break; case MotionEvent.ACTION_UP: if (check()) { // 正确图案 if (listener != null) { listener.onComplete(true); } for (int i = 0; i < stateSparseArray.size(); i++) { int index = stateSparseArray.keyAt(i); stateSparseArray.put(index, STATE_MOVE); } } else { // 错误图案 for (int i = 0; i < stateSparseArray.size(); i++) { int index = stateSparseArray.keyAt(i); stateSparseArray.put(index, STATE_ERROR); } linePaint.setColor(0xeeff0000); if (listener != null) { listener.onComplete(false); } } touchPoint = null; if (timer == null) { timer = new Timer(); } timer.schedule(new TimerTask() { @Override public void run() { linePath.reset(); linePaint.setColor(0xee0000ff); selectedList.clear(); stateSparseArray.clear(); postInvalidate(); } }, 1000); break; } invalidate(); return true; } 绘制各圆和各圆之间连接线段
@Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); drawCircle(canvas); drawLinePath(canvas); } private void drawCircle(Canvas canvas) { // 依次从索引 0 到索引 8，根据不同状态绘制圆点 for (int index = 0; index < rowCount * rowCount; index++) { int state = stateSparseArray.get(index); switch (state) { case STATE_NORMAL: innerCirclePaint.setColor(normalColor); outerCirclePaint.setColor(normalColor & 0x66ffffff); break; case STATE_MOVE: innerCirclePaint.setColor(moveColor); outerCirclePaint.setColor(moveColor & 0x66ffffff); break; case STATE_ERROR: innerCirclePaint.setColor(errorColor); outerCirclePaint.setColor(errorColor & 0x66ffffff); break; } canvas.drawCircle(points[index].x, points[index].y, radius, outerCirclePaint); canvas.drawCircle(points[index].x, points[index].y, radius / 2f, innerCirclePaint); } } 完整 View 代码：
/** * Created by star.tao on 2018/5/30. * email: xing-java@foxmail.com * github: https://github.com/xing16 */public class LockView extends View { private static final int DEFAULT_NORMAL_COLOR = 0xee776666; private static final int DEFAULT_MOVE_COLOR = 0xee0000ff; private static final int DEFAULT_ERROR_COLOR = 0xeeff0000; private static final int DEFAULT_ROW_COUNT = 3; private static final int STATE_NORMAL = 0; private static final int STATE_MOVE = 1; private static final int STATE_ERROR = 2; private int normalColor; // 无滑动默认颜色 private int moveColor; // 滑动选中颜色 private int errorColor; // 错误颜色 private float radius; // 外圆半径 private int rowCount; private PointF[] points; // 一维数组记录所有圆点的坐标点 private Paint innerCirclePaint; // 内圆画笔 private Paint outerCirclePaint; // 外圆画笔 private SparseIntArray stateSparseArray; private List<PointF> selectedList = new ArrayList<>(); private List<Integer> standardPointsIndexList = new ArrayList<>(); private Path linePath = new Path(); // 手指移动的路径 private Paint linePaint; private Timer timer; public LockView(Context context) { this(context, null); } public LockView(Context context, @Nullable AttributeSet attrs) { super(context, attrs); readAttrs(context, attrs); init(); } private void readAttrs(Context context, AttributeSet attrs) { TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.LockView); normalColor = typedArray.getColor(R.styleable.LockView_normalColor, DEFAULT_NORMAL_COLOR); moveColor = typedArray.getColor(R.styleable.LockView_moveColor, DEFAULT_MOVE_COLOR); errorColor = typedArray.getColor(R.styleable.LockView_errorColor, DEFAULT_ERROR_COLOR); rowCount = typedArray.getInteger(R.styleable.LockView_rowCount, DEFAULT_ROW_COUNT); typedArray.recycle(); } private void init() { stateSparseArray = new SparseIntArray(rowCount * rowCount); points = new PointF[rowCount * rowCount]; innerCirclePaint = new Paint(Paint.ANTI_ALIAS_FLAG); innerCirclePaint.setStyle(Paint.Style.FILL); outerCirclePaint = new Paint(Paint.ANTI_ALIAS_FLAG); outerCirclePaint.setStyle(Paint.Style.FILL); linePaint = new Paint(Paint.ANTI_ALIAS_FLAG); linePaint.setStyle(Paint.Style.STROKE); linePaint.setStrokeCap(Paint.Cap.ROUND); linePaint.setStrokeJoin(Paint.Join.ROUND); linePaint.setStrokeWidth(30); linePaint.setColor(moveColor); } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { super.onSizeChanged(w, h, oldw, oldh); // 外圆半径 = 相邻外圆之间间距 = 2倍内圆半径 radius = Math.min(w, h) / (2 * rowCount + rowCount - 1) * 1.0f; // 各个圆设置坐标点 for (int i = 0; i < rowCount * rowCount; i++) { points[i] = new PointF(0, 0); points[i].set((i % rowCount * 3 + 1) * radius, (i / rowCount * 3 + 1) * radius); } } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); int width = getSize(widthMeasureSpec); int height = getSize(heightMeasureSpec); setMeasuredDimension(width, height); } private int getSize(int measureSpec) { int mode = MeasureSpec.getMode(measureSpec); int size = MeasureSpec.getSize(measureSpec); if (mode == MeasureSpec.EXACTLY) { return size; } else if (mode == MeasureSpec.AT_MOST) { return Math.min(size, dp2Px(600)); } return dp2Px(600); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); drawCircle(canvas); drawLinePath(canvas); } private void drawCircle(Canvas canvas) { // 依次从索引 0 到索引 8，根据不同状态绘制圆点 for (int index = 0; index < rowCount * rowCount; index++) { int state = stateSparseArray.get(index); switch (state) { case STATE_NORMAL: innerCirclePaint.setColor(normalColor); outerCirclePaint.setColor(normalColor & 0x66ffffff); break; case STATE_MOVE: innerCirclePaint.setColor(moveColor); outerCirclePaint.setColor(moveColor & 0x66ffffff); break; case STATE_ERROR: innerCirclePaint.setColor(errorColor); outerCirclePaint.setColor(errorColor & 0x66ffffff); break; } canvas.drawCircle(points[index].x, points[index].y, radius, outerCirclePaint); canvas.drawCircle(points[index].x, points[index].y, radius / 2f, innerCirclePaint); } } /** * 绘制选中点之间相连的路径 * * @param canvas */ private void drawLinePath(Canvas canvas) { // 重置linePath linePath.reset(); // 选中点个数大于 0 时，才绘制连接线段 if (selectedList.size() > 0) { // 起点移动到按下点位置 linePath.moveTo(selectedList.get(0).x, selectedList.get(0).y); for (int i = 1; i < selectedList.size(); i++) { linePath.lineTo(selectedList.get(i).x, selectedList.get(i).y); } // 手指抬起时，touchPoint设置为null,使得已经绘制游离的路径，消失掉， if (touchPoint != null) { linePath.lineTo(touchPoint.x, touchPoint.y); } canvas.drawPath(linePath, linePaint); } } private PointF touchPoint; @Override public boolean onTouchEvent(MotionEvent event) { switch (event.getAction()) { case MotionEvent.ACTION_DOWN: reset(); case MotionEvent.ACTION_MOVE: if (touchPoint == null) { touchPoint = new PointF(event.getX(), event.getY()); } else { touchPoint.set(event.getX(), event.getY()); } for (int i = 0; i < rowCount * rowCount; i++) { // 是否触摸在圆的范围内 if (getDistance(touchPoint, points[i]) < radius) { stateSparseArray.put(i, STATE_MOVE); if (!selectedList.contains(points[i])) { selectedList.add(points[i]); } break; } } break; case MotionEvent.ACTION_UP: if (check()) { // 正确图案 if (listener != null) { listener.onComplete(true); } for (int i = 0; i < stateSparseArray.size(); i++) { int index = stateSparseArray.keyAt(i); stateSparseArray.put(index, STATE_MOVE); } } else { // 错误图案 for (int i = 0; i < stateSparseArray.size(); i++) { int index = stateSparseArray.keyAt(i); stateSparseArray.put(index, STATE_ERROR); } linePaint.setColor(0xeeff0000); if (listener != null) { listener.onComplete(false); } } touchPoint = null; if (timer == null) { timer = new Timer(); } timer.schedule(new TimerTask() { @Override public void run() { linePath.reset(); linePaint.setColor(0xee0000ff); selectedList.clear(); stateSparseArray.clear(); postInvalidate(); } }, 1000); break; } invalidate(); return true; } /** * 清除绘制图案的条件，当触发 invalidate() 时将清空图案 */ private void reset() { touchPoint = null; linePath.reset(); linePaint.setColor(0xee0000ff); selectedList.clear(); stateSparseArray.clear(); } public void onStop() { timer.cancel(); } private boolean check() { if (selectedList.size() != standardPointsIndexList.size()) { return false; } for (int i = 0; i < standardPointsIndexList.size(); i++) { Integer index = standardPointsIndexList.get(i); if (points[index] != selectedList.get(i)) { return false; } } return true; } public void setStandard(List<Integer> pointsList) { if (pointsList == null) { throw new IllegalArgumentException("standard points index can't null"); } if (pointsList.size() > rowCount * rowCount) { throw new IllegalArgumentException("standard points index list can't large to rowcount * columncount"); } standardPointsIndexList = pointsList; } private OnDrawCompleteListener listener; public void setOnDrawCompleteListener(OnDrawCompleteListener listener) { this.listener = listener; } public interface OnDrawCompleteListener { void onComplete(boolean isSuccess); } private float getDistance(PointF centerPoint, PointF downPoint) { return (float) Math.sqrt(Math.pow(centerPoint.x - downPoint.x, 2) + Math.pow(centerPoint.y - downPoint.y, 2)); } private int dp2Px(int dpValue) { return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dpValue, getResources().getDisplayMetrics()); }} 以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持VEVB武林网。
注：相关教程知识阅读请移步到Android开发频道。
