1、概述

最近需要用進度條，秉著不重複造輪子的原則，上github上搜索了一番，看了幾個覺得比較好看的ProgressBar，比如：daimajia的等。簡單看了下程式碼，基本都是繼承自View，徹徹底底的自定義了一個進度條。盯著那絢麗滾動條，忽然覺得，為什麼要通過View去寫一個滾動條，系統已經提供了ProgressBar以及屬於它的特性，我們沒必要重新去構建一個，但是系統的又比較醜，不同版本變現還不一定一樣。那麼得出我們的目標：改變系統ProgressBar的樣子。 

  對沒錯，我們沒有必要去從0打造一個ProgressBar，人家雖然長的不好看，但是特性以及穩定性還是剛剛的，我們只需要為其整下容就ok了。 

說到整容，大家都知道我們的控制元件是通過onDraw()畫出來的，那麼我們只需要去覆蓋它的onDraw()方法，自己寫下就ok 。 

對了，我建立了一個微信公眾號，歡迎關注，左邊欄目上掃一掃即可。

  接下來，我們貼下效果圖：

2、效果圖

1、橫向的進度條

2、圓形的進度條

沒錯，這就是我們的進度條效果，橫向的模仿了daimajia的進度條樣子。不過我們繼承子ProgressBar，簡單的為其整個容，程式碼清晰易懂 。為什麼說，易懂呢？

橫向那個進度條，大家會drawLine()和drawText()吧，那麼通過getWidth()拿到控制元件的寬度，再通過getProgress()拿到進度，按比例控制繪製線的長短，字的位置還不是分分鐘的事。

3、實現

橫向的滾動條繪製肯定需要一些屬性，比如已/未到達進度的顏色、寬度，文字的顏色、大小等。
本來呢，我是想通過系統ProgressBar的progressDrawable，從裡面提取一些屬性完成繪製需要的引數的。但是，最終呢，反而讓程式碼變得複雜。所以最終還是改用自定義屬性。 說道自定義屬性，大家應該已經不陌生了。

1、HorizontalProgressBarWithNumber

1、自定義屬性

values/attr_progress_bar.xml:

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <declare-styleable name="HorizontalProgressBarWithNumber">
        <attr name="progress_unreached_color" format="color" />
        <attr name="progress_reached_color" format="color" />
        <attr name="progress_reached_bar_height" format="dimension" />
        <attr name="progress_unreached_bar_height" format="dimension" />
        <attr name="progress_text_size" format="dimension" />
        <attr name="progress_text_color" format="color" />
        <attr name="progress_text_offset" format="dimension" />
        <attr name="progress_text_visibility" format="enum">
            <enum name="visible" value="0" />
            <enum name="invisible" value="1" />
        </attr>
    </declare-styleable>
    
    <declare-styleable name="RoundProgressBarWidthNumber">
        <attr name="radius" format="dimension" />
    </declare-styleable>

</resources>
 

2、構造中獲取

public class HorizontalProgressBarWithNumber extends ProgressBar
{

	private static final int DEFAULT_TEXT_SIZE = 10;
	private static final int DEFAULT_TEXT_COLOR = 0XFFFC00D1;
	private static final int DEFAULT_COLOR_UNREACHED_COLOR = 0xFFd3d6da;
	private static final int DEFAULT_HEIGHT_REACHED_PROGRESS_BAR = 2;
	private static final int DEFAULT_HEIGHT_UNREACHED_PROGRESS_BAR = 2;
	private static final int DEFAULT_SIZE_TEXT_OFFSET = 10;

	/**
	 * painter of all drawing things
	 */
	protected Paint mPaint = new Paint();
	/**
	 * color of progress number
	 */
	protected int mTextColor = DEFAULT_TEXT_COLOR;
	/**
	 * size of text (sp)
	 */
	protected int mTextSize = sp2px(DEFAULT_TEXT_SIZE);

	/**
	 * offset of draw progress
	 */
	protected int mTextOffset = dp2px(DEFAULT_SIZE_TEXT_OFFSET);

	/**
	 * height of reached progress bar
	 */
	protected int mReachedProgressBarHeight = dp2px(DEFAULT_HEIGHT_REACHED_PROGRESS_BAR);

	/**
	 * color of reached bar
	 */
	protected int mReachedBarColor = DEFAULT_TEXT_COLOR;
	/**
	 * color of unreached bar
	 */
	protected int mUnReachedBarColor = DEFAULT_COLOR_UNREACHED_COLOR;
	/**
	 * height of unreached progress bar
	 */
	protected int mUnReachedProgressBarHeight = dp2px(DEFAULT_HEIGHT_UNREACHED_PROGRESS_BAR);
	/**
	 * view width except padding
	 */
	protected int mRealWidth;
	
	protected boolean mIfDrawText = true;

	protected static final int VISIBLE = 0;

	public HorizontalProgressBarWithNumber(Context context, AttributeSet attrs)
	{
		this(context, attrs, 0);
	}

	public HorizontalProgressBarWithNumber(Context context, AttributeSet attrs,
			int defStyle)
	{
		super(context, attrs, defStyle);
		
		setHorizontalScrollBarEnabled(true);

		obtainStyledAttributes(attrs);

		mPaint.setTextSize(mTextSize);
		mPaint.setColor(mTextColor);

	}
	
	/**
	 * get the styled attributes
	 * 
	 * @param attrs
	 */
	private void obtainStyledAttributes(AttributeSet attrs)
	{
		// init values from custom attributes
		final TypedArray attributes = getContext().obtainStyledAttributes(
				attrs, R.styleable.HorizontalProgressBarWithNumber);

		mTextColor = attributes
				.getColor(
						R.styleable.HorizontalProgressBarWithNumber_progress_text_color,
						DEFAULT_TEXT_COLOR);
		mTextSize = (int) attributes.getDimension(
				R.styleable.HorizontalProgressBarWithNumber_progress_text_size,
				mTextSize);

		mReachedBarColor = attributes
				.getColor(
						R.styleable.HorizontalProgressBarWithNumber_progress_reached_color,
						mTextColor);
		mUnReachedBarColor = attributes
				.getColor(
						R.styleable.HorizontalProgressBarWithNumber_progress_unreached_color,
						DEFAULT_COLOR_UNREACHED_COLOR);
		mReachedProgressBarHeight = (int) attributes
				.getDimension(
						R.styleable.HorizontalProgressBarWithNumber_progress_reached_bar_height,
						mReachedProgressBarHeight);
		mUnReachedProgressBarHeight = (int) attributes
				.getDimension(
						R.styleable.HorizontalProgressBarWithNumber_progress_unreached_bar_height,
						mUnReachedProgressBarHeight);
		mTextOffset = (int) attributes
				.getDimension(
						R.styleable.HorizontalProgressBarWithNumber_progress_text_offset,
						mTextOffset);

		int textVisible = attributes
				.getInt(R.styleable.HorizontalProgressBarWithNumber_progress_text_visibility,
						VISIBLE);
		if (textVisible != VISIBLE)
		{
			mIfDrawText = false;
		}
		attributes.recycle();
	}

3、onMeasure

剛才不是出onDraw裡面寫寫就行了麼，為什麼要改onMeasure呢，主要是因為我們所有的屬性比如進度條寬度讓使用者自定義了，所以我們的測量也得稍微變下。

	@Override
	protected synchronized void onMeasure(int widthMeasureSpec,
			int heightMeasureSpec)
	{
		int heightMode = MeasureSpec.getMode(heightMeasureSpec);

		if (heightMode != MeasureSpec.EXACTLY)
		{

			float textHeight = (mPaint.descent() + mPaint.ascent());
			int exceptHeight = (int) (getPaddingTop() + getPaddingBottom() + Math
					.max(Math.max(mReachedProgressBarHeight,
							mUnReachedProgressBarHeight), Math.abs(textHeight)));

			heightMeasureSpec = MeasureSpec.makeMeasureSpec(exceptHeight,
					MeasureSpec.EXACTLY);
		}
		super.onMeasure(widthMeasureSpec, heightMeasureSpec);

	}

測量完，就到我們的onDraw了~~~

4、onDraw

@Override
	protected synchronized void onDraw(Canvas canvas)
	{
		canvas.save();
		//畫筆平移到指定paddingLeft， getHeight() / 2位置，注意以後座標都為以此為0，0
		canvas.translate(getPaddingLeft(), getHeight() / 2);

		boolean noNeedBg = false;
		//當前進度和總值的比例
		float radio = getProgress() * 1.0f / getMax();
		//已到達的寬度
		float progressPosX = (int) (mRealWidth * radio);
		//繪製的文字
		String text = getProgress() + "%";

		//拿到字型的寬度和高度
		float textWidth = mPaint.measureText(text);
		float textHeight = (mPaint.descent() + mPaint.ascent()) / 2;

		//如果到達最後，則未到達的進度條不需要繪製
		if (progressPosX + textWidth > mRealWidth)
		{
			progressPosX = mRealWidth - textWidth;
			noNeedBg = true;
		}

		// 繪製已到達的進度
		float endX = progressPosX - mTextOffset / 2;
		if (endX > 0)
		{
			mPaint.setColor(mReachedBarColor);
			mPaint.setStrokeWidth(mReachedProgressBarHeight);
			canvas.drawLine(0, 0, endX, 0, mPaint);
		}
	
		// 繪製文字
		if (mIfDrawText)
		{
			mPaint.setColor(mTextColor);
			canvas.drawText(text, progressPosX, -textHeight, mPaint);
		}

		// 繪製未到達的進度條
		if (!noNeedBg)
		{
			float start = progressPosX + mTextOffset / 2 + textWidth;
			mPaint.setColor(mUnReachedBarColor);
			mPaint.setStrokeWidth(mUnReachedProgressBarHeight);
			canvas.drawLine(start, 0, mRealWidth, 0, mPaint);
		}

		canvas.restore();

	}

	@Override
	protected void onSizeChanged(int w, int h, int oldw, int oldh)
	{
		super.onSizeChanged(w, h, oldw, oldh);
		mRealWidth = w - getPaddingRight() - getPaddingLeft();

	}

其實核心方法就是onDraw了，但是呢，onDraw也很簡單，繪製線、繪製文字、繪製線，結束。

還有兩個簡單的輔助方法：

	/**
	 * dp 2 px
	 * 
	 * @param dpVal
	 */
	protected int dp2px(int dpVal)
	{
		return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,
				dpVal, getResources().getDisplayMetrics());
	}

	/**
	 * sp 2 px
	 * 
	 * @param spVal
	 * @return
	 */
	protected int sp2px(int spVal)
	{
		return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP,
				spVal, getResources().getDisplayMetrics());

	}

好了，到此我們的橫向進度就結束了，是不是很簡單~~如果你是自定義View，你還得考慮progress的更新，考慮狀態的銷燬與恢復等等複雜的東西。

接下來看我們的RoundProgressBarWidthNumber圓形的進度條。

2、RoundProgressBarWidthNumber 

圓形的進度條和橫向的進度條基本變數都是一致的，於是我就讓RoundProgressBarWidthNumber extends HorizontalProgressBarWithNumber 了。

然後需要改變的就是測量和onDraw了：

完整程式碼：

package com.zhy.view;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint.Cap;
import android.graphics.Paint.Style;
import android.graphics.RectF;
import android.util.AttributeSet;

import com.zhy.library.view.R;

public class RoundProgressBarWidthNumber extends
		HorizontalProgressBarWithNumber {
	/**
	 * mRadius of view
	 */
	private int mRadius = dp2px(30);

	public RoundProgressBarWidthNumber(Context context) {
		this(context, null);
	}

	public RoundProgressBarWidthNumber(Context context, AttributeSet attrs) {
		super(context, attrs);

		mReachedProgressBarHeight = (int) (mUnReachedProgressBarHeight * 2.5f);
		TypedArray ta = context.obtainStyledAttributes(attrs,
				R.styleable.RoundProgressBarWidthNumber);
		mRadius = (int) ta.getDimension(
				R.styleable.RoundProgressBarWidthNumber_radius, mRadius);
		ta.recycle();

		mTextSize = sp2px(14);

		mPaint.setStyle(Style.STROKE);
		mPaint.setAntiAlias(true);
		mPaint.setDither(true);
		mPaint.setStrokeCap(Cap.ROUND);

	}

	@Override
	protected synchronized void onMeasure(int widthMeasureSpec,
			int heightMeasureSpec) {
		int heightMode = MeasureSpec.getMode(heightMeasureSpec);
		int widthMode = MeasureSpec.getMode(widthMeasureSpec);

		int paintWidth = Math.max(mReachedProgressBarHeight,
				mUnReachedProgressBarHeight);

		if (heightMode != MeasureSpec.EXACTLY) {

			int exceptHeight = (int) (getPaddingTop() + getPaddingBottom()
					+ mRadius * 2 + paintWidth);
			heightMeasureSpec = MeasureSpec.makeMeasureSpec(exceptHeight,
					MeasureSpec.EXACTLY);
		}
		if (widthMode != MeasureSpec.EXACTLY) {
			int exceptWidth = (int) (getPaddingLeft() + getPaddingRight()
					+ mRadius * 2 + paintWidth);
			widthMeasureSpec = MeasureSpec.makeMeasureSpec(exceptWidth,
					MeasureSpec.EXACTLY);
		}

		super.onMeasure(heightMeasureSpec, heightMeasureSpec);

	}

	@Override
	protected synchronized void onDraw(Canvas canvas) {

		String text = getProgress() + "%";
		// mPaint.getTextBounds(text, 0, text.length(), mTextBound);
		float textWidth = mPaint.measureText(text);
		float textHeight = (mPaint.descent() + mPaint.ascent()) / 2;

		canvas.save();
		canvas.translate(getPaddingLeft(), getPaddingTop());
		mPaint.setStyle(Style.STROKE);
		// draw unreaded bar
		mPaint.setColor(mUnReachedBarColor);
		mPaint.setStrokeWidth(mUnReachedProgressBarHeight);
		canvas.drawCircle(mRadius, mRadius, mRadius, mPaint);
		// draw reached bar
		mPaint.setColor(mReachedBarColor);
		mPaint.setStrokeWidth(mReachedProgressBarHeight);
		float sweepAngle = getProgress() * 1.0f / getMax() * 360;
		canvas.drawArc(new RectF(0, 0, mRadius * 2, mRadius * 2), 0,
				sweepAngle, false, mPaint);
		// draw text
		mPaint.setStyle(Style.FILL);
		canvas.drawText(text, mRadius - textWidth / 2, mRadius - textHeight,
				mPaint);

		canvas.restore();

	}

}

繪製的過程呢？

先繪製一個細一點的圓，然後繪製一個粗一點的弧度，二者疊在一起就行。文字呢，繪製在中間~~~總體，沒什麼程式碼量。

好了，兩個進度條就到這了，是不是發現簡單很多。總體設計上，存在些問題，如果抽取一個BaseProgressBar用於獲取公共的屬性；然後不同樣子的進度條繼承分別實現自己的測量和樣子，這樣結構可能會清晰些~~~

4、使用

佈局檔案

<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:zhy="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        android:padding="25dp" >

        <com.zhy.view.HorizontalProgressBarWithNumber
            android:id="@+id/id_progressbar01"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="50dip"
            android:padding="5dp" />

       

        <com.zhy.view.HorizontalProgressBarWithNumber
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="50dip"
            android:padding="5dp"
            android:progress="50"
            zhy:progress_text_color="#ffF53B03"
            zhy:progress_unreached_color="#ffF7C6B7" />

        <com.zhy.view.RoundProgressBarWidthNumber
            android:id="@+id/id_progress02"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="50dip"
            android:padding="5dp"
            android:progress="30" />

        <com.zhy.view.RoundProgressBarWidthNumber
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="50dip"
            android:padding="5dp"
            android:progress="50"
            zhy:progress_reached_bar_height="20dp"
            zhy:progress_text_color="#ffF53B03"
            zhy:radius="60dp" />
     
    </LinearLayout>

</ScrollView>

MainActivity

package com.zhy.sample.progressbar;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;

import com.zhy.annotation.Log;
import com.zhy.view.HorizontalProgressBarWithNumber;

public class MainActivity extends Activity {

	private HorizontalProgressBarWithNumber mProgressBar;
	private static final int MSG_PROGRESS_UPDATE = 0x110;

	private Handler mHandler = new Handler() {
		@Log
		public void handleMessage(android.os.Message msg) {
			int progress = mProgressBar.getProgress();
			mProgressBar.setProgress(++progress);
			if (progress >= 100) {
				mHandler.removeMessages(MSG_PROGRESS_UPDATE);
				
			}
			mHandler.sendEmptyMessageDelayed(MSG_PROGRESS_UPDATE, 100);
		};
	};

	@Log
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		mProgressBar = (HorizontalProgressBarWithNumber) findViewById(R.id.id_progressbar01);
		mHandler.sendEmptyMessage(MSG_PROGRESS_UPDATE);

	}

}

最後，本篇部落格的目的呢？就是為了說下，類似ProgressBar這樣的控制元件，如果你只是想去改變顯示的樣子，完全沒必要從0去建立，複寫onDraw即可，當然是個人觀點，提出供大家參考。