轉自：http://www.jcodecraeer.com/a/anzhuokaifa/androidkaifa/2014/0813/1645.html

原生的ProgressBar在不同的主題下風格迥異，有矩形條狀的，有代表載入進行中的圓圈風格的，在4.0的holo風格下這些ProgressBar都還比較好看，但是在非holo風格下讓人厭煩。我不排斥使用原生控制元件，但是有時我們的app可能比較個性化，需要更有個性的ProgressBar。

下面這款開源ProgressBar就比較有個性。

NumberProgressBar

該控制元件雖然也叫ProgressBar，但是和sdk中的ProgressBar

用法：

xml中

<com.daimajia.numberprogressbar.NumberProgressBar
    android:id="@+id/number_progress_bar"
    style="@style/NumberProgressBar_Default" />

NumberProgressBar_Default 

NumberProgressBar_Passing_Green 

NumberProgressBar_Relax_Blue 

NumberProgressBar_Grace_Yellow 

NumberProgressBar_Warning_Red 

NumberProgressBar_Funny_Orange 

NumberProgressBar_Beauty_Red 

NumberProgressBar_Twinkle_Night

對應的外觀如下：

除了直接用已經定義好的style，你還可以通過設定屬性來改變外觀。

NumberProgressBar的一些屬性：

reached area和unreached area

• 顏色

• 高度

文字部分，描述程序的百分比數字

• 顏色

• 字型大小

• 是否可見
  

• 和reached area與unreached area之間的距離

整個bar

• 最大進度 max progress

• 當前進度 current progress

比如預設情況下

<com.daimajia.numberprogressbar.NumberProgressBar
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        custom:progress_unreached_color="#CCCCCC"
        custom:progress_reached_color="#3498DB"
        custom:progress_unreached_bar_height="0.75dp"
        custom:progress_reached_bar_height="1.5dp"
        custom:progress_text_size="10sp"
        custom:progress_text_color="#3498DB"
        custom:progress_text_offset="1dp"
        custom:progress_text_visibility="visible"
        custom:max="100"
        custom:progress="80" />

如上面的第一張圖所示，github專案中的demo實現了NumberProgressBar的動畫效果，但是這個動畫效果並不是NumberProgressBar自帶的，而是在外部通過不斷呼叫setProgress做到的，demo中

final NumberProgressBar bnp = (NumberProgressBar)findViewById(R.id.numberbar1);
counter = 0;
timer = new Timer();
timer.schedule(new TimerTask() {
    @Override
    public void run() {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                bnp.incrementProgressBy(1);
                counter ++;
                if (counter == 110) {
                    bnp.setProgress(0);
                    counter=0;
                }
            }
        });
    }
}, 1000, 100);

NumberProgressBar的原始碼實現：

如果你已經學會了如何自定義一個view，那麼NumberProgressBar的程式碼是很容易看懂的。這裡想指出的是有個細節我個人持保留意見，那就是作者在onMeasure方法中呼叫了自己實現的measure方法，在View的繪製中是先measure然後再在measure方法中呼叫onMeasure，而繼承子view的子類一般只重寫onMeasure方法。雖然這裡並不會引起什麼錯誤，但是我覺得還是遵守view的繪製流程比較好。

最後貼出NumberProgressBar的java部分的程式碼，程式碼不多：

package com.daimajia.numberprogressbar;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.os.Bundle;
import android.os.Parcelable;
import android.util.AttributeSet;
import android.view.View;
/**
 * Created by daimajia on 14-4-30.
 */
public class NumberProgressBar extends View {
    private Context mContext;
    /**
     * The max progress, default is 100
     */
    private int mMax = 100;
    /**
     * current progress, can not exceed the max progress.
     */
    private int mProgress = 0;
    /**
     * the progress area bar color
     */
    private int mReachedBarColor;
    /**
     * the bar unreached area color.
     */
    private int mUnreachedBarColor;
    /**
     * the progress text color.
     */
    private int mTextColor;
    /**
     * the progress text size
     */
    private float mTextSize;
    /**
     * the height of the reached area
     */
    private float mReachedBarHeight;
    /**
     * the height of the unreached area
     */
    private float mUnreachedBarHeight;
    private final int default_text_color = Color.rgb(66, 145, 241);
    private final int default_reached_color = Color.rgb(66,145,241);
    private final int default_unreached_color = Color.rgb(204, 204, 204);
    private final float default_progress_text_offset;
    private final float default_text_size;
    private final float default_reached_bar_height;
    private final float default_unreached_bar_height;
    /**
     * for save and restore instance of progressbar.
     */
    private static final String INSTANCE_STATE = "saved_instance";
    private static final String INSTANCE_TEXT_COLOR = "text_color";
    private static final String INSTANCE_TEXT_SIZE = "text_size";
    private static final String INSTANCE_REACHED_BAR_HEIGHT = "reached_bar_height";
    private static final String INSTANCE_REACHED_BAR_COLOR = "reached_bar_color";
    private static final String INSTANCE_UNREACHED_BAR_HEIGHT = "unreached_bar_height";
    private static final String INSTANCE_UNREACHED_BAR_COLOR = "unreached_bar_color";
    private static final String INSTANCE_MAX = "max";
    private static final String INSTANCE_PROGRESS = "progress";
    private static final int PROGRESS_TEXT_VISIBLE = 0;
    private static final int PROGRESS_TEXT_INVISIBLE = 1;
    /**
     * the width of the text that to be drawn
     */
    private float mDrawTextWidth;
    /**
     * the drawn text start
     */
    private float mDrawTextStart;
    /**
     *the drawn text end
     */
    private float mDrawTextEnd;
    /**
     * the text that to be drawn in onDraw()
     */
    private String mCurrentDrawText;
    /**
     * the Paint of the reached area.
     */
    private Paint mReachedBarPaint;
    /**
     * the Painter of the unreached area.
     */
    private Paint mUnreachedBarPaint;
    /**
     * the Painter of the progress text.
     */
    private Paint mTextPaint;
    /**
     * Unreached Bar area to draw rect.
     */
    private RectF mUnreachedRectF = new RectF(0,0,0,0);
    /**
     * reached bar area rect.
     */
    private RectF mReachedRectF = new RectF(0,0,0,0);
    /**
     * the progress text offset.
     */
    private float mOffset;
    /**
     * determine if need to draw unreached area
     */
    private boolean mDrawUnreachedBar = true;
    private boolean mDrawReachedBar = true;
    private boolean mIfDrawText = true;
    public enum ProgressTextVisibility{
        Visible,Invisible
    };
    public NumberProgressBar(Context context) {
        this(context, null);
    }
    public NumberProgressBar(Context context, AttributeSet attrs) {
        this(context, attrs, R.attr.numberProgressBarStyle);
    }
    public NumberProgressBar(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        mContext = context;
        default_reached_bar_height = dp2px(1.5f);
        default_unreached_bar_height = dp2px(1.0f);
        default_text_size = sp2px(10);
        default_progress_text_offset = dp2px(3.0f);
        //load styled attributes.
        final TypedArray attributes = context.getTheme().obtainStyledAttributes(attrs, R.styleable.NumberProgressBar,
                defStyleAttr, 0);
        mReachedBarColor = attributes.getColor(R.styleable.NumberProgressBar_progress_reached_color, default_reached_color);
        mUnreachedBarColor = attributes.getColor(R.styleable.NumberProgressBar_progress_unreached_color,default_unreached_color);
        mTextColor = attributes.getColor(R.styleable.NumberProgressBar_progress_text_color,default_text_color);
        mTextSize = attributes.getDimension(R.styleable.NumberProgressBar_progress_text_size, default_text_size);
        mReachedBarHeight = attributes.getDimension(R.styleable.NumberProgressBar_progress_reached_bar_height,default_reached_bar_height);
        mUnreachedBarHeight = attributes.getDimension(R.styleable.NumberProgressBar_progress_unreached_bar_height,default_unreached_bar_height);
        mOffset = attributes.getDimension(R.styleable.NumberProgressBar_progress_text_offset,default_progress_text_offset);
        int textVisible = attributes.getInt(R.styleable.NumberProgressBar_progress_text_visibility,PROGRESS_TEXT_VISIBLE);
        if(textVisible != PROGRESS_TEXT_VISIBLE){
            mIfDrawText = false;
        }
        setProgress(attributes.getInt(R.styleable.NumberProgressBar_progress,0));
        setMax(attributes.getInt(R.styleable.NumberProgressBar_max, 100));
        //
        attributes.recycle();
        initializePainters();
    }
    @Override
    protected int getSuggestedMinimumWidth() {
        return (int)mTextSize;
    }
    @Override
    protected int getSuggestedMinimumHeight() {
        return Math.max((int)mTextSize,Math.max((int)mReachedBarHeight,(int)mUnreachedBarHeight));
    }
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        setMeasuredDimension(measure(widthMeasureSpec,true), measure(heightMeasureSpec,false));
    }
    private int measure(int measureSpec,boolean isWidth){
        int result;
        int mode = MeasureSpec.getMode(measureSpec);
        int size = MeasureSpec.getSize(measureSpec);
        int padding = isWidth?getPaddingLeft()+getPaddingRight():getPaddingTop()+getPaddingBottom();
        if(mode == MeasureSpec.EXACTLY){
            result = size;
        }else{
            result = isWidth ? getSuggestedMinimumWidth() : getSuggestedMinimumHeight();
            result += padding;
            if(mode == MeasureSpec.AT_MOST){
                if(isWidth) {
                    result = Math.max(result, size);
                }
                else{
                    result = Math.min(result, size);
                }
            }
        }
        return result;
    }
    @Override
    protected void onDraw(Canvas canvas) {
        if(mIfDrawText){
            calculateDrawRectF();
        }else{
            calculateDrawRectFWithoutProgressText();
        }
        if(mDrawReachedBar){
            canvas.drawRect(mReachedRectF,mReachedBarPaint);
        }
        if(mDrawUnreachedBar) {
            canvas.drawRect(mUnreachedRectF, mUnreachedBarPaint);
        }
        if(mIfDrawText)
            canvas.drawText(mCurrentDrawText,mDrawTextStart,mDrawTextEnd,mTextPaint);
    }
    private void initializePainters(){
        mReachedBarPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mReachedBarPaint.setColor(mReachedBarColor);
        mUnreachedBarPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mUnreachedBarPaint.setColor(mUnreachedBarColor);
        mTextPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mTextPaint.setColor(mTextColor);
        mTextPaint.setTextSize(mTextSize);
    }
    private void calculateDrawRectFWithoutProgressText(){
        mReachedRectF.left = getPaddingLeft();
        mReachedRectF.top = getHeight()/2.0f - mReachedBarHeight / 2.0f;
        mReachedRectF.right = (getWidth() - getPaddingLeft() - getPaddingRight() )/(getMax()*1.0f) * getProgress() + getPaddingLeft();
        mReachedRectF.bottom = getHeight()/2.0f + mReachedBarHeight / 2.0f;
        mUnreachedRectF.left = mReachedRectF.right;
        mUnreachedRectF.right = getWidth() - getPaddingRight();
        mUnreachedRectF.top = getHeight()/2.0f +  - mUnreachedBarHeight / 2.0f;
        mUnreachedRectF.bottom = getHeight()/2.0f  + mUnreachedBarHeight / 2.0f;
    }
    private void calculateDrawRectF(){
        mCurrentDrawText = String.format("%d%%",getProgress()*100/getMax());
        mDrawTextWidth = mTextPaint.measureText(mCurrentDrawText);
        if(getProgress() == 0){
            mDrawReachedBar = false;
            mDrawTextStart = getPaddingLeft();
        }else{
            mDrawReachedBar = true;
            mReachedRectF.left = getPaddingLeft();
            mReachedRectF.top = getHeight()/2.0f - mReachedBarHeight / 2.0f;
            mReachedRectF.right = (getWidth() - getPaddingLeft() - getPaddingRight() )/(getMax()*1.0f) * getProgress() - mOffset + getPaddingLeft();
            mReachedRectF.bottom = getHeight()/2.0f + mReachedBarHeight / 2.0f;
            mDrawTextStart = (mReachedRectF.right + mOffset);
        }
        mDrawTextEnd =  (int) ((getHeight() / 2.0f) - ((mTextPaint.descent() + mTextPaint.ascent()) / 2.0f)) ;
        if((mDrawTextStart + mDrawTextWidth )>= getWidth() - getPaddingRight()){
            mDrawTextStart = getWidth() - getPaddingRight() - mDrawTextWidth;
            mReachedRectF.right = mDrawTextStart - mOffset;
        }
        float unreachedBarStart = mDrawTextStart + mDrawTextWidth + mOffset;
        if(unreachedBarStart >= getWidth() - getPaddingRight()){
            mDrawUnreachedBar = false;
        }else{
            mDrawUnreachedBar = true;
            mUnreachedRectF.left = unreachedBarStart;
            mUnreachedRectF.right = getWidth() - getPaddingRight();
            mUnreachedRectF.top = getHeight()/2.0f +  - mUnreachedBarHeight / 2.0f;
            mUnreachedRectF.bottom = getHeight()/2.0f  + mUnreachedBarHeight / 2.0f;
        }
    }
    /**
     * get progress text color
     * @return progress text color
     */
    public int getTextColor() {
        return mTextColor;
    }
    /**
     * get progress text size
     * @return progress text size
     */
    public float getProgressTextSize() {
        return mTextSize;
    }
    public int getUnreachedBarColor() {
        return mUnreachedBarColor;
    }
    public int getReachedBarColor() {
        return mReachedBarColor;
    }
    public int getProgress() {
        return mProgress;
    }
    public int getMax() {
        return mMax;
    }
    public float getReachedBarHeight(){
        return mReachedBarHeight;
    }
    public float getUnreachedBarHeight(){
        return mUnreachedBarHeight;
    }
    public void setProgressTextSize(float TextSize) {
        this.mTextSize = TextSize;
        mTextPaint.setTextSize(mTextSize);
        invalidate();
    }
    public void setProgressTextColor(int TextColor) {
        this.mTextColor = TextColor;
        mTextPaint.setColor(mTextColor);
        invalidate();
    }
    public void setUnreachedBarColor(int BarColor) {
        this.mUnreachedBarColor = BarColor;
        mUnreachedBarPaint.setColor(mReachedBarColor);
        invalidate();
    }
    public void setReachedBarColor(int ProgressColor) {
        this.mReachedBarColor = ProgressColor;
        mReachedBarPaint.setColor(mReachedBarColor);
        invalidate();
    }
    public void setMax(int Max) {
        if(Max > 0){
            this.mMax = Max;
            invalidate();
        }
    }
    public void incrementProgressBy(int by){
        if(by > 0){
            setProgress(getProgress() + by);
        }
    }
    public void setProgress(int Progress) {
        if(Progress <= getMax()  && Progress >= 0){
            this.mProgress = Progress;
            invalidate();
        }
    }
    @Override
    protected Parcelable onSaveInstanceState() {
        final Bundle bundle = new Bundle();
        bundle.putParcelable(INSTANCE_STATE,super.onSaveInstanceState());
        bundle.putInt(INSTANCE_TEXT_COLOR,getTextColor());
        bundle.putFloat(INSTANCE_TEXT_SIZE, getProgressTextSize());
        bundle.putFloat(INSTANCE_REACHED_BAR_HEIGHT,getReachedBarHeight());
        bundle.putFloat(INSTANCE_UNREACHED_BAR_HEIGHT,getUnreachedBarHeight());
        bundle.putInt(INSTANCE_REACHED_BAR_COLOR,getReachedBarColor());
        bundle.putInt(INSTANCE_UNREACHED_BAR_COLOR,getUnreachedBarColor());
        bundle.putInt(INSTANCE_MAX,getMax());
        bundle.putInt(INSTANCE_PROGRESS,getProgress());
        return bundle;
    }
    @Override
    protected void onRestoreInstanceState(Parcelable state) {
        if(state instanceof Bundle){
            final Bundle bundle = (Bundle)state;
            mTextColor = bundle.getInt(INSTANCE_TEXT_COLOR);
            mTextSize = bundle.getFloat(INSTANCE_TEXT_SIZE);
            mReachedBarHeight = bundle.getFloat(INSTANCE_REACHED_BAR_HEIGHT);
            mUnreachedBarHeight = bundle.getFloat(INSTANCE_UNREACHED_BAR_HEIGHT);
            mReachedBarColor = bundle.getInt(INSTANCE_REACHED_BAR_COLOR);
            mUnreachedBarColor = bundle.getInt(INSTANCE_UNREACHED_BAR_COLOR);
            initializePainters();
            setMax(bundle.getInt(INSTANCE_MAX));
            setProgress(bundle.getInt(INSTANCE_PROGRESS));
            super.onRestoreInstanceState(bundle.getParcelable(INSTANCE_STATE));
            return;
        }
        super.onRestoreInstanceState(state);
    }
    public float dp2px(float dp) {
        final float scale = getResources().getDisplayMetrics().density;
        return  dp * scale + 0.5f;
    }
    public float sp2px(float sp){
        final float scale = getResources().getDisplayMetrics().scaledDensity;
        return sp * scale;
    }
    public void setProgressTextVisibility(ProgressTextVisibility visibility){
        if(visibility == ProgressTextVisibility.Visible){
            mIfDrawText = true;
        }else{
            mIfDrawText = false;
        }
        invalidate();
    }
}