Android实现百分比下载进度条效果

<?xml version="1.0" encoding="utf-8"?> 
<resources> 
 <declare-styleable name="downloadProgressBar"> 
 <attr name="dptextsize" format="dimension"/> 
 </declare-styleable> 
</resources> 

package com.ywl5320.downloadprogressdemo.downloadview; 
 
import android.content.Context; 
import android.content.res.TypedArray; 
import android.graphics.Canvas; 
import android.graphics.Paint; 
import android.graphics.Rect; 
import android.util.AttributeSet; 
import android.view.View; 
import android.view.ViewTreeObserver.OnGlobalLayoutListener; 
 
import com.ywl5320.downloadprogressdemo.R; 
 
/** 
 * 下载进度条 
 * 
 * @author ywl 
 * 
 */ 
public class DownLoadProgressbar extends View { 
 
 private Paint paint = new Paint(); // 绘制背景灰色线条画笔 
 private Paint paintText = new Paint(); // 绘制下载进度画笔 
 private float offset = 0f; // 下载偏移量 
 private float maxvalue = 0f; // 下载的总大小 
 private float currentValue = 0f; // 下载了多少 
 private Rect mBound = new Rect(); // 获取百分比数字的长宽 
 private String percentValue = "0%"; // 要显示的现在百分比 
 private float offsetRight = 0f; // 灰色线条距离右边的距离 
 private int textSize = 25; // 百分比的文字大小 
 private float offsetTop = 18f; // 距离顶部的偏移量 
 
 public DownLoadProgressbar(Context context) { 
 this(context, null); 
 // TODO Auto-generated constructor stub 
 } 
 
 public DownLoadProgressbar(Context context, AttributeSet attribute) { 
 this(context, attribute, 0); 
 } 
 
 public DownLoadProgressbar(Context context, AttributeSet attrs, 
  int defStyleAttr) { 
 super(context, attrs, defStyleAttr); 
 // TODO Auto-generated constructor stub 
 // 获取自定义属性，给textsize赋初始值 
 TypedArray t = getContext().obtainStyledAttributes(attrs, 
  R.styleable.downloadProgressBar); 
 textSize = (int) t.getDimension( 
  R.styleable.downloadProgressBar_dptextsize, 36); 
 getTextWidth(); 
 } 
 
 @Override 
 protected void onDraw(Canvas canvas) { 
 // TODO Auto-generated method stub 
 super.onDraw(canvas); 
 // 绘制底色 
 paint.setColor(getResources().getColor(R.color.no1_gray_light)); 
 paint.setStrokeWidth(1); 
 canvas.drawLine(0, offsetTop, getWidth(), offsetTop, paint); 
 // 绘制进度条颜色 
 paint.setColor(getResources().getColor(R.color.no2_orange)); 
 paint.setStrokeWidth(2); 
 canvas.drawLine(0, offsetTop, offset, offsetTop, paint); 
 // 绘制白色区域及百分比 
 paint.setColor(getResources().getColor(R.color.no3_white)); 
 paint.setStrokeWidth(1); 
 paintText.setColor(getResources().getColor(R.color.no2_orange)); 
 paintText.setTextSize(textSize); 
 paintText.setAntiAlias(true); 
 paintText.getTextBounds(percentValue, 0, percentValue.length(), mBound); 
 canvas.drawLine(offset, offsetTop, offset + mBound.width() + 4, offsetTop, paint); 
 canvas.drawText(percentValue, offset, offsetTop + mBound.height() / 2 - 2, paintText); 
 } 
 
 /** 
 * 设置当前进度值 
 * 
 * @param currentValue 
 */ 
 public void setCurrentValue(float currentValue) { 
 this.currentValue = currentValue; 
 int value = (int) (this.currentValue / maxvalue * 100); 
 if (value < 100) { 
  percentValue = value + "%"; 
 } else { 
  percentValue = "100%"; 
 } 
 initCurrentProgressBar(); 
 invalidate(); 
 } 
 
 /** 
 * 设置最大值 
 * 
 * @param maxValue 
 */ 
 public void setMaxValue(float maxValue) { 
 this.maxvalue = maxValue; 
 } 
 
 /** 
 * 获取当前进度条长度 
 * 
 * @param maxValue 
 * @param currentValue 
 * @return 
 */ 
 public void initCurrentProgressBar() { 
 getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() { 
 
  @Override 
  public void onGlobalLayout() { 
  // TODO Auto-generated method stub 
  if (currentValue < maxvalue) { 
   offset = (getWidth() - offsetRight) * currentValue / maxvalue; 
  } else { 
   offset = getWidth() - offsetRight; 
  } 
  } 
 }); 
 
 } 
 
 /** 
 * 获取“100%”的宽度 
 */ 
 public void getTextWidth() { 
 Paint paint = new Paint(); 
 Rect rect = new Rect(); 
 paint.setTextSize(textSize); 
 paint.setAntiAlias(true); 
 paint.getTextBounds("100%", 0, "100%".length(), rect); 
 offsetRight = rect.width() + 5; 
 } 
} 

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
 xmlns:tools="http://schemas.android.com/tools" 
 xmlns:ywl="http://schemas.android.com/apk/res/com.ywl5320.downloadprogressdemo" <!-- 这就是为自定义属性添加命名空间，注意res后的是：程序包名--> 
 android:layout_width="match_parent" 
 android:layout_height="match_parent" 
 android:background="@color/no3_white" 
 tools:context="${relativePackage}.${activityClass}" > 
 
 <TextView 
 android:id="@+id/tv_start" 
 android:layout_width="match_parent" 
 android:layout_height="50dip" 
 android:layout_below="@+id/rl_progress" 
 android:layout_marginTop="40dip" 
 android:layout_marginLeft="20dip" 
 android:layout_marginRight="20dip" 
 android:gravity="center" 
 android:background="@drawable/btn_blue_selector" 
 android:text="开始"/> 
 
 <RelativeLayout 
 android:id="@+id/rl_progress" 
 android:layout_width="match_parent" 
 android:layout_marginLeft="20dip" 
 android:layout_marginRight="20dip" 
 android:layout_marginTop="30dip" 
 android:layout_height="50dip"> 
 <TextView 
  android:id="@+id/tv_size" 
  android:layout_width="wrap_content" 
  android:layout_height="wrap_content" 
  android:layout_marginTop="4dip" 
  android:textColor="@color/no5_gray_silver" 
  android:textSize="12sp" /> 
 
 <TextView 
  android:id="@+id/tv_speed" 
  android:layout_width="wrap_content" 
  android:layout_height="wrap_content" 
  android:layout_alignParentRight="true" 
  android:layout_marginTop="6dip" 
  android:textColor="@color/no5_gray_silver" 
  android:textSize="12sp" /> 
 
 <com.ywl5320.downloadprogressdemo.downloadview.DownLoadProgressbar 
  android:id="@+id/dp_game_progress" 
  android:layout_width="match_parent" 
  android:layout_height="wrap_content" 
  ywl:dptextsize="14sp" <!-- 这里设置控件的字体大小为14sp --> 
  android:layout_below="@+id/tv_size"> 
 </com.ywl5320.downloadprogressdemo.downloadview.DownLoadProgressbar> 
 </RelativeLayout> 
 
</RelativeLayout> 

package com.ywl5320.downloadprogressdemo; 
 
import android.app.Activity; 
import android.os.Bundle; 
import android.os.Handler; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.TextView; 
 
import com.ywl5320.downloadprogressdemo.downloadview.DownLoadProgressbar; 
 
public class MainActivity extends Activity { 
 
 private TextView mStart; 
 private TextView mSize; 
 private TextView mSpeed; 
 private DownLoadProgressbar mProgress; 
 private int max = 100; //总的大小 
 private int current = 0; //当前下载大小 
 private String speed = "1"; //下载速度 
 
 @Override 
 protected void onCreate(Bundle savedInstanceState) { 
 super.onCreate(savedInstanceState); 
 setContentView(R.layout.activity_main); 
 mStart = (TextView) findViewById(R.id.tv_start); 
 mProgress = (DownLoadProgressbar) findViewById(R.id.dp_game_progress); 
 mSize = (TextView) findViewById(R.id.tv_size); 
 mSpeed = (TextView) findViewById(R.id.tv_speed); 
 //初始化下载进度 
 mSize.setText(current + "MB/" + max + "MB"); 
 //初始化下载速度 
 mSpeed.setText(speed + "MB/s"); 
 mStart.setOnClickListener(new OnClickListener() { 
 
  @Override 
  public void onClick(View v) { 
  // TODO Auto-generated method stub 
  start(); 
  } 
 }); 
 } 
 
 //循环模拟下载过程 
 public void start() { 
 if (current <= max) { 
  mSize.setText(current + "MB/" + max + "MB"); 
  mSpeed.setText(speed + "MB/s"); 
  mProgress.setMaxValue(max); 
  mProgress.setCurrentValue(current); 
  handler.postDelayed(runnable, 100); 
 } else { 
  handler.removeCallbacks(runnable); 
 } 
 
 } 
 
 Handler handler = new Handler(); 
 Runnable runnable = new Runnable() { 
 @Override 
 public void run() { 
  // TODO Auto-generated method stub 
  current = current + 1; 
  start(); 
 } 
 }; 
 
}