今天我做的是一个自定义刻度尺控件，由于项目需求需要使用刻度尺那样滑动选择，由于对自定义控件的认识还不够深入，于是花了一周多时间才把这个控件给整出来，也是呕心沥血的经历啊，也让我对自定义控件有了自己的认识，废话不多说，先上一个简单的效果图，大家可以看看，如有需求可以直接拿去使用

效果图如下：只是我的一个简单Demo，效果有点丑陋了点，希望海涵！

效果已经出来接下来就是代码部分了，一看就只是一般的控件很难实现，于是就开始了我的自定义View之旅，每次自定义完后总是会收获很多东西，如下是我的代码：

package android.tst.com.myapplication;

import android.annotation.SuppressLint;

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.text.Layout;

import android.text.TextPaint;

import android.util.AttributeSet;

import android.view.MotionEvent;

import android.view.VelocityTracker;

import android.view.View;

import android.view.ViewConfiguration;

import android.widget.Scroller;

/**

* 卷尺控件类。由于时间比较紧，只有下班后有时间，因此只实现了基本功能。

* 细节问题包括滑动过程中widget边缘的刻度显示问题等

* @version create：2014年8月26日

*/

@SuppressLint("ClickableViewAccessibility")

public class RulerView extends View {

public interface OnValueChangeListener {

public void onValueChange(float value);

}

public static final int MOD_TYPE_HALF = 2;

public static final int MOD_TYPE_ONE = 10;

private static final int ITEM_HALF_DIVIDER = 10;

private static final int ITEM_ONE_DIVIDER = 10;

private static final int ITEM_MAX_HEIGHT = 20;

private static final int ITEM_MIN_HEIGHT = 10;

private static final int TEXT_SIZE = 7;

private float mDensity;

private int mValue = 50, mMaxValue = 100, mModType = MOD_TYPE_HALF,

mLineDivider = ITEM_HALF_DIVIDER;

// private int mValue = 50, mMaxValue = 500, mModType = MOD_TYPE_ONE,

// mLineDivider = ITEM_ONE_DIVIDER;

private int mLastX, mMove;

private int mWidth, mHeight;

private int mMinVelocity;

private Scroller mScroller;

private VelocityTracker mVelocityTracker;

private OnValueChangeListener mListener;

@SuppressWarnings("deprecation")

public RulerView(Context context, AttributeSet attrs) {

super(context, attrs);

mScroller = new Scroller(getContext());

mDensity = getContext().getResources().getDisplayMetrics().density;

mMinVelocity = ViewConfiguration.get(getContext())

.getScaledMinimumFlingVelocity();

}

/**

*

* 考虑可扩展，但是时间紧迫，只可以支持两种类型效果图中两种类型

*

* @param value

* 初始值

* @param maxValue

* 最大值

* @param model

* 刻度盘精度：

* {@link MOD_TYPE_HALF}

* {@link MOD_TYPE_ONE}

*/

public void initViewParam(int defaultValue, int maxValue, int model) {

switch (model) {

case MOD_TYPE_HALF:

mModType = MOD_TYPE_HALF;

mLineDivider = ITEM_HALF_DIVIDER;

mValue = defaultValue * 2;

mMaxValue = maxValue * 2;

break;

case MOD_TYPE_ONE:

mModType = MOD_TYPE_ONE;

mLineDivider = ITEM_ONE_DIVIDER;

mValue = defaultValue;

mMaxValue = maxValue;

break;

default:

break;

}

invalidate();

mLastX = 0;

mMove = 0;

notifyValueChange();

}

/**

* 设置用于接收结果的监听器

*

* @param listener

*/

public void setValueChangeListener(OnValueChangeListener listener) {

mListener = listener;

}

/**

* 获取当前刻度值

*

* @return

*/

public float getValue() {

return mValue;

}

public void setValue(int value){

mValue = value;

notifyValueChange();

postInvalidate();

}

public void setValueToChange(int what) {

mValue += what;

notifyValueChange();

postInvalidate();

}

@Override

protected void onLayout(boolean changed, int left, int top, int right,

int bottom) {

mWidth = getWidth();

mHeight = getHeight();

super.onLayout(changed, left, top, right, bottom);

}

@Override

protected void onDraw(Canvas canvas) {

super.onDraw(canvas);

drawScaleLine(canvas);

// drawWheel(canvas);

drawMiddleLine(canvas);

}

/**

* 从中间往两边开始画刻度线

*

* @param canvas

*/

private void drawScaleLine(Canvas canvas) {

canvas.save();

Paint linePaint = new Paint();

linePaint.setStrokeWidth(2);

linePaint.setColor(Color.rgb(141, 189, 225));

TextPaint textPaint = new TextPaint(Paint.ANTI_ALIAS_FLAG);

textPaint.setColor(Color.rgb(68, 135, 188));

textPaint.setTextSize(TEXT_SIZE * mDensity);

int width = mWidth, drawCount = 0;

float xPosition = 0, textWidth = Layout.getDesiredWidth("0", textPaint);

for (int i = 0; drawCount <= 4 * width; i++) {

int numSize = String.valueOf(mValue + i).length();

// 前

xPosition = (width / 2 - mMove) + i * mLineDivider * mDensity;

if (xPosition + getPaddingRight() < mWidth) {

if ((mValue + i) % mModType == 0) {

linePaint.setColor(Color.rgb(68, 135, 188));

canvas.drawLine(xPosition, getPaddingTop(), xPosition,

mDensity * ITEM_MAX_HEIGHT, linePaint);

if (mValue + i <= mMaxValue) {

switch (mModType) {

case MOD_TYPE_HALF:

canvas.drawText(

String.valueOf((mValue + i) / 2),

countLeftStart(mValue + i, xPosition,

textWidth),

getHeight() - textWidth, textPaint);

break;

case MOD_TYPE_ONE:

canvas.drawText(String.valueOf(mValue + i),

xPosition - (textWidth * numSize / 2),

getHeight() - textWidth, textPaint);

break;

default:

break;

}

}

} else {

linePaint.setColor(Color.rgb(141, 189, 225));

// linePaint.setColor(Color.rgb(68, 135, 188));

canvas.drawLine(xPosition, getPaddingTop(), xPosition,

mDensity * ITEM_MIN_HEIGHT, linePaint);

}

}

// 后

xPosition = (width / 2 - mMove) - i * mLineDivider * mDensity;

if (xPosition > getPaddingLeft()) {

if ((mValue - i) % mModType == 0) {

linePaint.setColor(Color.rgb(68, 135, 188));

canvas.drawLine(xPosition, getPaddingTop(), xPosition,

mDensity * ITEM_MAX_HEIGHT, linePaint);

if (mValue - i >= 0) {

switch (mModType) {

case MOD_TYPE_HALF:

canvas.drawText(

String.valueOf((mValue - i) / 2),

countLeftStart(mValue - i, xPosition,

textWidth),

getHeight() - textWidth, textPaint);

break;

case MOD_TYPE_ONE:

canvas.drawText(String.valueOf(mValue - i),

xPosition - (textWidth * numSize / 2),

getHeight() - textWidth, textPaint);

break;

default:

break;

}

}

} else {

linePaint.setColor(Color.rgb(141, 189, 225));

canvas.drawLine(xPosition, getPaddingTop(), xPosition,

mDensity * ITEM_MIN_HEIGHT, linePaint);

}

}

drawCount += 2 * mLineDivider * mDensity;

}

canvas.restore();

}

/**

* 计算没有数字显示位置的辅助方法

*

* @param value

* @param xPosition

* @param textWidth

* @return

*/

private float countLeftStart(int value, float xPosition, float textWidth) {

float xp = 0f;

if (value < 20) {

xp = xPosition - (textWidth * 1 / 2);

} else {

xp = xPosition - (textWidth * 2 / 2);

}

return xp;

}

/**

* 画中间的红色指示线、阴影等。指示线两端简单的用了两个矩形代替

*

* @param canvas

*/

private void drawMiddleLine(Canvas canvas) {

// TOOD 常量太多，暂时放这，最终会放在类的开始，放远了怕很快忘记

int gap = 12, indexWidth = 2, indexTitleWidth = 24, indexTitleHight = 10, shadow = 6;

String color = "#66999999";

canvas.save();

Paint redPaint = new Paint();

redPaint.setStrokeWidth(indexWidth);

redPaint.setColor(Color.RED);

canvas.drawLine(mWidth / 2, 0, mWidth / 2, mHeight, redPaint);

canvas.restore();

}

@Override

public boolean onTouchEvent(MotionEvent event) {

int action = event.getAction();

int xPosition = (int) event.getX();

if (mVelocityTracker == null) {

mVelocityTracker = VelocityTracker.obtain();

}

mVelocityTracker.addMovement(event);

switch (action) {

case MotionEvent.ACTION_DOWN:

mScroller.forceFinished(true);

mLastX = xPosition;

mMove = 0;

break;

case MotionEvent.ACTION_MOVE:

getParent().requestDisallowInterceptTouchEvent(true);

mMove += (mLastX - xPosition);

changeMoveAndValue();

break;

case MotionEvent.ACTION_UP:

case MotionEvent.ACTION_CANCEL:

countMoveEnd();

countVelocityTracker(event);

getParent().requestDisallowInterceptTouchEvent(false);

return false;

// break;

default:

break;

}

mLastX = xPosition;

return true;

}

private void countVelocityTracker(MotionEvent event) {

mVelocityTracker.computeCurrentVelocity(1000);

float xVelocity = mVelocityTracker.getXVelocity();

if (Math.abs(xVelocity) > mMinVelocity) {

mScroller.fling(0, 0, (int) xVelocity, 0, Integer.MIN_VALUE,

Integer.MAX_VALUE, 0, 0);

}

}

private void changeMoveAndValue() {

int tValue = (int) (mMove / (mLineDivider * mDensity));

if (Math.abs(tValue) > 0) {

mValue += tValue;

mMove -= tValue * mLineDivider * mDensity;

if (mValue <= 0 || mValue > mMaxValue) {

mValue = mValue <= 0 ? 0 : mMaxValue;

mMove = 0;

mScroller.forceFinished(true);

}

notifyValueChange();

}

postInvalidate();

}

private void countMoveEnd() {

int roundMove = Math.round(mMove / (mLineDivider * mDensity));

mValue = mValue + roundMove;

mValue = mValue <= 0 ? 0 : mValue;

mValue = mValue > mMaxValue ? mMaxValue : mValue;

mLastX = 0;

mMove = 0;

notifyValueChange();

postInvalidate();

}

private void notifyValueChange() {

if (null != mListener) {

if (mModType == MOD_TYPE_ONE) {

mListener.onValueChange(mValue);

}

if (mModType == MOD_TYPE_HALF) {

mListener.onValueChange(mValue / 2f);

}

}

}

@Override

public void computeScroll() {

super.computeScroll();

if (mScroller.computeScrollOffset()) {

if (mScroller.getCurrX() == mScroller.getFinalX()) { // over

countMoveEnd();

} else {

int xPosition = mScroller.getCurrX();

mMove += (mLastX - xPosition);

changeMoveAndValue();

mLastX = xPosition;

}

}

}

@Override

public boolean dispatchTouchEvent(MotionEvent event) {

getParent().requestDisallowInterceptTouchEvent(true);

return super.dispatchTouchEvent(event);

}

}

这是我的自定义View部分的代码，下面就是在布局中的使用了

android:id="@+id/tv_values"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:padding="10dp"

android:gravity="center"

android:textColor="@android:color/holo_red_dark"/>

android:id="@+id/rv_view"

android:layout_width="match_parent"

android:layout_height="60dp"/>

android:layout_width="match_parent"

android:orientation="horizontal"

android:layout_height="wrap_content">

android:id="@+id/btn_jia"

android:layout_width="0dp"

android:layout_height="wrap_content"

android:text="+"

android:textSize="25sp"

android:gravity="center"

android:layout_marginRight="15dp"

android:layout_weight="1"/>

android:id="@+id/btn_jian"

android:layout_width="0dp"

android:layout_height="wrap_content"

android:text="-"

android:layout_marginLeft="15dp"

android:textSize="25sp"

android:gravity="center"

android:layout_weight="1"/>

如上根据效果图，我需要一个TextView进行显示，还有就是我的自定义刻度尺控件了，接下来就是两个Button控件加减。

接下来就是在Activity中的使用了

首先需要一个Handler进行更新TextView中的值

Handler handler = new Handler() {

@Override

public void handleMessage(Message msg) {

tv_values.setText(rv_view.getValue() + "Kg");

};

};

其次就是初始化相关的操作了

private void deployRulerView(){

rv_view= (RulerView) findViewById(R.id.rv_view);

btn_jia= (Button) findViewById(R.id.btn_jia);

btn_jian= (Button) findViewById(R.id.btn_jian);

tv_values= (TextView) findViewById(R.id.tv_values);

//设置RulerView的初始值

rv_view.setValue(60);

//初始化刻度尺范围

rv_view.initViewParam(60, 200, RulerView.MOD_TYPE_ONE);

rv_view.setValueChangeListener(new RulerView.OnValueChangeListener() {

@Override

public void onValueChange(float value) {

handler.sendMessage(new Message());

}

});

tv_values.setText(60+"KG");

//给两个控件添加监听事件

btn_jia.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

rv_view.setValueToChange(1);

}

});

btn_jian.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

rv_view.setValueToChange(-1);

}

});

}

到这里整个过程已经完成了，如果不好的地方尽情吐槽，整个过程，最复杂的莫过于自定义中的绘制过程，但是一切的问题当你静下心好好去实现时，那一切的问题都就不存在了。

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脚本之家。