<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.progresstest.MainActivity"
tools:ignore="MergeRootFrame" >
<com.example.progresstest.ProgressViewTest 
android:id="@+id/progressbar"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
</LinearLayout>

package com.example.progresstest;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.view.View;
public class ProgressViewTest extends View {
/**进度条最大值*/
private float maxCount;
/**进度条当前值*/
private float currentCount;
/**画笔*/
private Paint mPaint;
private int mWidth,mHeight;
public ProgressViewTest(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
// TODO Auto-generated constructor stub
}
public ProgressViewTest(Context context, AttributeSet attrs) {
super(context, attrs);
// TODO Auto-generated constructor stub
}
public ProgressViewTest(Context context) {
super(context);
// TODO Auto-generated constructor stub
}
/***
* 设置最大的进度值
* @param maxCount
*/
public void setMaxCount(float maxCount) {
this.maxCount = maxCount;
}
/**
* 得到最大进度值
*/
public double getMaxCount(){
return maxCount;
}
/***
* 设置当前的进度值
* @param currentCount
*/
public void setCurrentCount(float currentCount) {
this.currentCount = currentCount > maxCount ? maxCount : currentCount;
/**
* invalidate()是用来刷新View的，必须是在UI线程中进行工作。比如在修改某个view的显示时，
* 调用invalidate()才能看到重新绘制的界面。invalidate()的调用是把之前的旧的view从主UI
* 线程队列中pop掉。 
*/
invalidate();
}
@Override
protected void onDraw(Canvas canvas) {
// TODO Auto-generated method stub
super.onDraw(canvas);
mPaint = new Paint();
//设置抗锯齿效果
mPaint.setAntiAlias(true);
//设置画笔颜色
mPaint.setColor(Color.BLACK);
int round = mHeight/2;
/**
* RectF：绘制矩形，四个参数分别是left,top,right,bottom
* 类型是单精度浮点数
*/
RectF rf = new RectF(0, 0, mWidth, mHeight);
/*绘制圆角矩形，背景色为画笔颜色*/
canvas.drawRoundRect(rf, round, round, mPaint);
/*设置progress内部是灰色*/
mPaint.setColor(Color.rgb(211, 211, 211));
RectF rectBlackBg = new RectF(2, 2, mWidth-2, mHeight-2);
canvas.drawRoundRect(rectBlackBg, round, round, mPaint);
//设置进度条进度及颜色
float section = currentCount/maxCount;
RectF rectProgressBg = new RectF(3, 3, (mWidth-3)*section, mHeight-3);
if(section!=0.0f){
mPaint.setColor(Color.GREEN);
}else{
mPaint.setColor(Color.TRANSPARENT);
}
canvas.drawRoundRect(rectProgressBg, round, round, mPaint);
}
//dip * scale + 0.5f * (dip >= 0 ? 1 : -1)
private int dipToPx(int dip){
float scale = getContext().getResources().getDisplayMetrics().density;
return (int) (dip * scale + 0.5f * (dip >= 0 ? 1 : -1));//加0.5是为了四舍五入
}
/**指定自定义控件在屏幕上的大小,onMeasure方法的两个参数是由上一层控件
* 传入的大小，而且是模式和尺寸混合在一起的数值，需要MeasureSpec.getMode(widthMeasureSpec)
* 得到模式，MeasureSpec.getSize(widthMeasureSpec)得到尺寸
* 
*/
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// TODO Auto-generated method stub
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
int widthSpecMode = MeasureSpec.getMode(widthMeasureSpec);
int heightSpecMode = MeasureSpec.getMode(heightMeasureSpec);
int widthSpecSize = MeasureSpec.getSize(widthMeasureSpec);
int heightSpecSize = MeasureSpec.getSize(heightMeasureSpec);
//MeasureSpec.EXACTLY，精确尺寸
if (widthSpecMode == MeasureSpec.EXACTLY || widthSpecMode == MeasureSpec.AT_MOST) {
mWidth = widthSpecSize;
} else {
mWidth = 0;
}
//MeasureSpec.AT_MOST，最大尺寸，只要不超过父控件允许的最大尺寸即可，MeasureSpec.UNSPECIFIED未指定尺寸
if (heightSpecMode == MeasureSpec.AT_MOST || heightSpecMode == MeasureSpec.UNSPECIFIED) {
mHeight = dipToPx(20);
} else {
mHeight = heightSpecSize;
}
//设置控件实际大小
setMeasuredDimension(mWidth, mHeight);
}
}

package com.example.progresstest;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
public class MainActivity extends ActionBarActivity {
private ProgressViewTest progress;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
progress = (ProgressViewTest) findViewById(R.id.progressbar);
progress.setMaxCount(100);
new Thread(new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
for (int i = 0; i <=progress.getMaxCount(); i++) {
Message msg = new Message();
msg.arg1 = i;
msg.what = 0x01;
handler.sendMessage(msg);
try {
//每隔0.1秒进度前进1
Thread.sleep(100);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}).start();
}
Handler handler = new Handler(){
public void handleMessage(Message msg) {
if(msg.what==0x01){
progress.setCurrentCount(msg.arg1);
}
};
};
}