Android自定义水平渐变进度条

先看进度条的效果：

具体实现：

新建类，继承自View，在onDraw中进行绘制：

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.LinearGradient;
import android.graphics.Paint;
import android.graphics.RectF;
import android.graphics.Shader;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;

/**
 *
 * 自定义 进度条
 * Created by wenjing.tang on 2017/8/7.
 */

public class CustomizedProgressBar extends View {

 private float maxCount = 100; //进度条最大值
 private float currentCount; //进度条当前值
 // private Paint mPaint ;
 private int mWidth,mHeight;
 private Context mContext;

 public CustomizedProgressBar(Context context, AttributeSet attrs, int defStyleAttr) {
  super(context, attrs, defStyleAttr);
  initView(context);
 }

 public CustomizedProgressBar(Context context, AttributeSet attrs) {
  super(context, attrs);
  initView(context);
 }

 public CustomizedProgressBar(Context context) {
  super(context);
  initView(context);
 }

 private void initView(Context context) {
  mContext=context;
 }

 @Override
 protected void onDraw(Canvas canvas) {
  super.onDraw(canvas);
  Paint mPaint = new Paint();
  mPaint.setAntiAlias(true);
  int round = mHeight/2; //半径

  mPaint.setColor(getResources().getColor(R.color.white_alpha)); //设置边框背景颜色
  RectF rectBg = new RectF(0, 0, mWidth, mHeight);
  canvas.drawRoundRect(rectBg, round, round, mPaint);//绘制 最外面的大 圆角矩形，背景为白色

  float section = currentCount/maxCount; //进度条的比例
  RectF rectProgressBg = new RectF(0, 0, mWidth*section, mHeight);

  Log.e("CustomizedProgressBar", currentCount+"");
  Log.e("CustomizedProgressBar", section+"");

  //Paint设置setColor(白色无透明)和setShader，只让setShader生效；不然前面setColor设置了透明度，透明度会生效，和setShader效果叠加
  mPaint.setColor(getResources().getColor(R.color.white));
  mPaint.setShader(getLinearGradient());
  canvas.drawRoundRect(rectProgressBg, round, round, mPaint); //最左边的圆角矩形

  if (maxCount != currentCount){ //如果不是100%，绘制第三段矩形
   RectF rectProgressBg2 = new RectF(mWidth*section-round, 0, mWidth*section, mHeight);
   mPaint.setShader(getLinearGradient());
   canvas.drawRect(rectProgressBg2, mPaint);
  }
 }

 private LinearGradient linearGradient;
 private LinearGradient getLinearGradient(){
  if(linearGradient==null){
   linearGradient = new LinearGradient(0, 0, getWidth(), mHeight, new int[]{mContext.getResources().getColor(R.color.progress_color_1),
     mContext.getResources().getColor(R.color.progress_color_2)}, null, Shader.TileMode.CLAMP); //根据R文件中的id获取到color
  }
  return linearGradient;
 }

 private int dipToPx(int dip) {
  float scale = getContext().getResources().getDisplayMetrics().density;
  return (int) (dip * scale + 0.5f * (dip >= 0 ? 1 : -1));
 }

 /***
  * 设置最大的进度值
  * @param maxCount 最大的进度值
  */
 public void setMaxCount(float maxCount) {
  this.maxCount = maxCount;
 }

 /***
  * 设置当前的进度值
  * @param currentCount 当前进度值
  */
 public void setCurrentCount(float currentCount) {
  this.currentCount = currentCount > maxCount ? maxCount : currentCount;
  invalidate();
 }

 public float getMaxCount() {
  return maxCount;
 }

 public float getCurrentCount() {
  return currentCount;
 }

 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
  int widthSpecMode = MeasureSpec.getMode(widthMeasureSpec);
  int widthSpecSize = MeasureSpec.getSize(widthMeasureSpec);
  int heightSpecMode = MeasureSpec.getMode(heightMeasureSpec);
  int heightSpecSize = MeasureSpec.getSize(heightMeasureSpec);
  if (widthSpecMode == MeasureSpec.EXACTLY || widthSpecMode == MeasureSpec.AT_MOST) {
   mWidth = widthSpecSize;
  } else {
   mWidth = 0;
  }
  if (heightSpecMode == MeasureSpec.AT_MOST || heightSpecMode == MeasureSpec.UNSPECIFIED) {
   mHeight = dipToPx(18);
  } else {
   mHeight = heightSpecSize;
  }
  setMeasuredDimension(mWidth, mHeight);
 }
}

其中用到的一些资源文件如下：

<!--自定义进度条背景颜色-->
<color name="white_alpha">#0c000000</color>

<!--自定义进度条渐变颜色-->
<color name="progress_color_1">#ff916b</color>
<color name="progress_color_2">#ffa94c</color>

要注意的是，在上面Java代码中，mPaint.setColor(getResources().getColor(R.color.white));这行很重要，因为进度条总共有三层，第一层是最外面的背景，第二层是进度，第三层如果不是100%才绘制，由于第一层背景有透明度，所以setColor设置了透明度，但虽然setShader，透明度还是会生效，两者效果叠加，效果是这样：

加上之后，Paint 第二次设置 setColor (白色无透明)和 setShader，只让 setShader 生效，进度条才会达到满意的效果；

用法：

Java代码中：

 customizedProgressBar.setMaxCount(100);
 integrity = dataCount/TOTAL_COUNT *100; //根据自己情况来初始化完整度
 customizedProgressBar.setCurrentCount((int) integrity);
 mTvtDataIntegrity.setText("完整度" + (int) integrity +"%");      

xml文件中（不需要文字显示也可以）：

 <RelativeLayout
     android:layout_width="match_parent"
     android:layout_height="18dp"
     android:layout_marginStart="66dp"
     android:layout_marginEnd="66dp"
     android:layout_centerVertical="true">

     <com.text.widget.CustomizedProgressBar
      android:id="@+id/progress"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:layout_centerInParent="true"/>

     <TextView
      android:id="@+id/tv_data_integrity"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:gravity="center"
      tools:text="完整度35%"
      android:textSize="10sp"
      android:layout_centerInParent="true"/>
 </RelativeLayout>

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我们。